LIBRARY >TAT£ PLANT BOAJUl December 1942 E-584 THE DEPENDENCE OF AGRICULTURE ON THE BEEKEEPING INDUSTRY— A REVIEW Prepared by the Division of Bee Culture CONTENTS Page Introduction 1 Pollination requirements of plants 4 Reasons for inadequacy of wild pollinating insects 6 Increased areas under cultivation 8 Concentrated plantings 12 Rail-fence elimination and heavy grazing 14 Forest, brush, and grass fires 15 The automobile and paved roads 16 Poisoning from insecticides 16 Value of the honeybee in pollinating crops 17 Fruit crops 18 Seed crops 30 Forage crops grown for seed in Oregon 38 Truck-crop plants grown for seed in California 39 INTRODUCTION Most people have some appreciation that honeybees are the only source of honey and beeswax. Few realize, however, that, although the beekeeping industry produces in excess of 200 million pounds of honey and 4 million pounds of beeswax annually, these are merely byproducts, and that its principal role is in the pollination of the many agricultural crops for the production of seed and fruit. Without the help of insects to effect pol- lination, many species of plants will not set seed or produce fruit no matter how well they are cultivated, fertilized, and protected from diseases and pests. Although the honeybee is the most important pollinating insect, it is but one of many species of the Apoidea group so necessary for the per- petuation of flowering plants. Various species of flies, beetles, and other insects also visit flowers and to some extent pollinate them. Nectar and pollen are rarely the principal food of such insects, whereas these substances supply the entire nourishment of both the young and adults of honeybees and wild bees. When nature shows a proper balance between plants and pollinating insects, both the plants and the insects flourish. Agricultural develop- ment, however, has seriously interfered with this balance. It has demanded the growing of certain plants in enormous acreages and unwittingly destroyed native pollinating insects as well as their nesting places. As a result the burden of pollination has been increased to such an extent that wild bees are no longer adequate or dependable, particularly where agriculture is highly developed. Both the reduction in wild beneficial insects and the increase in the crops requiring insect pollination have been gradual. While these changes were occurring commercial beekeeping had its inception, and fortunately so, since the presence of honeybees in most areas has not only overcome the shortage of wild pollinators but has permitted more thorough pollination than would have been possible under natural conditions. Con- sequently, plant growers and farmers generally have not been greatly con- cerned about pollination simply because someone else has taken care of the bees. No State or Federal agency has assumed the responsibility for con- serving wild pollinating insects, although some species, bee for bee, are more efficient than honeybees and will work under more adverse conditions. For this reason measures should be taken to conserve our native pollinating insects. In practically all agricultural regions honeybees are the most numerous flower-visiting insects, and in many places the depletion of wild pollinators is so acute that honeybees have to be brought in especially for pollination. The fertilization of plant flowers is so essential that beekeeping must be carried on to maintain a profitable agriculture, and it may be necessary to subsidize the keeping of bees, since there is no practical substitute for honeybees in the transfer of pollen from flower to flower and plant to plant. Owing to conditions brought about by the present war the beekeeping industry must be safeguarded. Beekeeping can be mastered only through years of experience. It cannot be learned as a trade is learned, and there is no floating population of persons seeking employment in bee- keeping. The fact that bees have a propensity for stinging discourages many persons from keeping bees, and only certain persons possess the proper temperament to be beekeepers. For these reasons every experienced bee- keeper should be encouraged to continue with his bees. Since only exper- ienced persons can handle bees, it is almost impossible to find anyone capable of taking care of an apiary in the absence of the owner. Therefore, beekeepers called into the military service often have no other choice than to kill the bees, melt the combs, and sell the wax and used equipment. Bees are not good collateral, for neither the banks nor the Government will accept them as security for loans. - 3 - The present ceiling on honey prices and the demoralized condition of the honey market are proving highly discouraging to beekeepers. Another obstacle is the difficulty of obtaining beekeepers' supplies. These facts, bined with the high wages obtainable in industry, are causing many small-scale, sideline beekeepers, having 50 to 100 colonies, to give up their bees and take employment in factories and elsewhere. Such curtailment cf the beekeeping industry will not only reduce the production of honey and beeswax but seriously interfere with adequate pollination. In the following pages literature is cited in support of the premise (I), that v, ild pollinating insects are deficient in number adequately to pollinate our agricultural crops, and (2) that at least 50 agricultural crops depend upon honeybees for pollination or yield more abundantly when bees are plentiful. 1/ The specific fruit and seed crops mentioned in these references are tabulated below: Fruit Crops Seed Crops Almond Apple Apricot Avocado Blackberry Blueberry and huckleberry Cherry Cranberry Cucumber Gooseberry Grape Muskmelon Peach and nectarine Pear Persimmon, native Plum and prune Strawberry Tung Walnut Watermelon Alfalfa Asparagus Broccoli Brussels sprouts Buckwheat Cabbage Cantaloup Carrot Cauliflower Clovers (alsike, crimson, red, strawberry, white, and Ladino white) Collards Cotton Cucumber Kale Kohlrabi Lotus Onion Pepper Pumpkin Radish Rape Rutabaga Soybean Squash Sunflower Sweet clover Trefoil Turnip Vetches Watermelon 1/ These quotations are for the most part from plant spojialists, with only a few from authorities on apiculture. POLLINATION REQUIREMENTS OF PLANTS* Fletcher, S. W. 1941. Pollination. Standard cyclopedia of horticulture, by L. H. Bailey, v. 3, pp. 2734-2737. New York. p. 2734: ... it is well known that while the flowers of many plants may be readily fertilized by their own pollen, the offspring are stronger when pollen from another plant or another variety has had access to the flower. Sometimes pollen from a foreign variety is absolutely essential to the best fruit-formation. This is particularly true of certain varieties of the pear. A poor quality of fruit can be prevented only by growing together different varieties. Again, although a plant may readily pollinate itself, yet the pollen from another plant or variety may be prepotent over its own. This is to s ay » if the plant be Poll inated_ by ,its_own__pollen aleng_with. that_of a foreign variety, that of the foreign variety will usually effect ■'fer- tilization. pp. 2734-5: The flowers of insect-pollinated plants, on the other hand, are usually showy, and have nectar or fragrance, or both, pollen is more or less moist or sticky, so that it is not easily away... As the insect reaches &own for the nectar, which is near the bottom of the flower, some parts of its body are sure to become dusted with pollen.., Thus cross-pollination, or the transfer of pollen m the anthers of one flower to the pistil of another, is accom- plished. [Bees collecting pollen are just as valuable as those gathering In visiting large flowers they may be more effective, as they go directly to the reproductive organs.] The value of crossing to plants was first clearly proved by Charles Darwin in 1859. . . From the observations of Kolreuter, Sprengel, (ght, and his own exhaustive experiments, Darwin showed that con- tinued self-fsrtiljzation is likely to result in inferior offspring;; while cross-fertilization, within certain limits, gives greater vigor to the offspring. Cross-fertilization between different flowers on the same plant usually has no appreciable advantage. p. 2736: In the selection of a pollinizer, several points must be considered: (1) The two sorts must blossom approximately at the same time in order that cross-pollination may be possible. The trans- fer of pollen from one variety to another is performed mainly by Insects. Waugh and Backhouse have shown that practically none of the pollen of the plum and other stone-fruits is carried by wind, it being moist and sticky. The same is true of pears, but apple pollen 2 The underlining in the references does not appear in the original citations but has been added for emphasis. - 5 - somewhat drier and . ind -blown to a slight extent. The honey- b3e_.tg t i!3[t_ESii©tl'z2arrier . Hqqp_er estimates that in England 80 per the _cross-pqlIiti i ;do'ne by 'the '-' h e, 15 Q3r ..cent, by. V.5i Id Jjees, T[especially__the bi .'oee,.. and 5 per cent by miscellaneous insects . [If this was true for England with its large areas devoted to hedge- rows, woods, and small-scale farming with many wild areas suitable for the nes I i ve bees, then in this country with its large blocks of clean cultivation, dwindling; wild areas, its large sheep population and much greater use of arsenicals, the percentage of pollination effected by the . honeybee must be even higher.] pp. 2736-7: Orchard pollination, however, is a broader problem than the mere detection of varieties that are inclined to be unfruitful when planted alone, and discovering which are the best pollinizers for each of them. Experiments in crossing' and observation^ in oj indicate that nearly all varieties^ whether. self— sterile or self— fertile, wiljl produce sore or better fruit with foreign pollen than witfi/thgjf own. ■ • Yellow Newtown is distinctly self-fertile in Oregon, yet Lewis noted a decided improvement in the fruit when Jonathan and Grimes pollen was used upon it. He concluded, "All varieties of_;p_ fruits , .at IVast of apples and pqarg . evon though they may bq termed se l.f- f b ti i 1 § ,* b'eilef itefl" by having other. varieties planted w them as pollinizers . " [A survey of the literature shows that the last statement is not confined to fruit but is applicable to many agricultural crops as well.] MacDaniels, L. H. 1923. Pollination studies in Mew York State. Amer. Soc . Hort. Sci. Proc. 1928: 129-137. p. 137: The_ value of having bees e " s in the orchard ..?.0.ra.§„.s3a;s2]l?? ' :..only w]2 ' es can fly, satisfactory cross-poll inat ion will be_ whereas it would not have been accomplished if sources of gcod pollen and abundant insects were not close at ha It is for such minimum conditions for cress-pollination that the grower should provide. is also ..evident .that in any .region the_lack of pollen carriers in the orchard at blooming time ' may be 'the limiting factor in the setof fruit and that _in order to properly unders the pollination problem a study of th-j inserts ] ity.in thai r relation to pollina- tion is necessary . MacDaniels, L. H. 1930. Practical aspects of the pollination problem. N. Y. State Hort. Soc. Proc. 1930: 195-202. p. 201: In the foregoing paragraphs much has been said of the limitations of bees in pollen distribution. It must be borne - 6 - in mind, however, that for all that, bees are still the most effective pollen, carriers ..there are _and that they are the only insect that can be managed by the orchardist. Marshall, R. E., Johnston, Stanley, Hootman, H. D., and 7/ells, H. M. 1929. Pollination of orchard fruits in Michigan. Mich. Agr. Expt. Sta. Spec. Bui. 188, 38 pp. p . 38 : The commercial fruit grower is almost entirely depend- ent on the common honey bee for the transfer of pollen from one varie- ty to another. There are not enough bees in many orchards to insure the setting of a full crop of fruit in years when weather conditions are not favorable for maximum insect activity at blooming time. REASONS FOR INADEQUACY OF WILD POLLINATING INSECTS Authorities universally admit the importance of wild insects in pollinating agricultural crops; yet no State or Federal organization is especially concerned with the conservation of beneficial insects. It is apparent, therefore, that the destruction of pollinating insects has not been fully recognized as the important cause of decreased seed and fruit production in many crops that are benefited by insect pollination. In considering the part played by wild pollinating insects, it should be borne in mind that most species, with the exception of bumblebees, are solitary insects and reproduce slowly, and since the females have to fly in search of food they are subjected to such hazards as weather, fast- moving automobiles, natural enemies, etc. Many of the solitary bees are ground-nesting and are consequently easily destroyed in areas where agri- cultural practices demand frequent cultivation of the soil. Certain species of flies, beetles, and other insects effect pollina- tion but are considered of minor importance. Megee, C. R., and Kelty, R. M. 1932. The influence of bees upon clover and alfalfa seed production. Mich. Agr. Expt. Sta. Quart. Bui. 14: 271-277. p. 271: It is common observation that along with the decrease in the numbers of bumble bees and other wild bees there has been a decrease in the production of clover seed. p. 277: Bumble bees are effective pollinating agents, but, due to their relative scarcity in the clover and alfalfa seed producing districts of northern Michigan cannot be depended on for pollination purposes. - 7 - Metcalf, C. L., and Flint, W. P. 1S28. Destructive and useful insects; their habits and control. 918 pp. New York. p. 264: Under farming conditions great changes take place in the character of the plants grown on the land. There are no longer a great number of species, generally intermixed, but a few species occupying the land in nearly pure stands of thousands and hundreds of thousands of acres. This affects the insect population of the land in two general ways. Many of those which depend on the plants of one family, or even on one species of plant, find their food supply :. off, except in the small uncultivated areas and may nearly, or quite, disappear from the region, as certain species of the bilibugs in drained bottom lands. Vansell, G. H. 1342. Factors affecting the usefulness of honeybees in pollination. U.S. Dept. Agr. Cir. 650, 31 pp. p. 2: The orchards were located on top of a ridge, which was flanked on both sides by uncultivated lands, including both timber and manzanita-ceanothus brush. pp. 5-6: In the Camino district honeybees were the most common visitors to the blossoms, blowflies were next, and other insects \. scarce. a rule honeybees visit the blossoms of only one plant species on each field trip, while most other insects frequently shift from one species to another. For this reason no other insect compares favorably with the honeybee in pollen-distributing activity. Only honeybees and wild bees collected pollen for removal to their nests. Ants were surprisingly common in the orchard blossoms, feeding on nectar at temperatures well below that at which flying insects cease activity. Ants were observed -working in early morning, late evening, and during cold rainy periods, but probably they do not often move from tree to tree. Pollen seemed to offer no special attraction to them, but nectar and possibly sap did, because frequently these ants were engaged in taking nectar and in biting into tender twigs and the tiny fruit before the petals had fallen away. Bumblebees worked in the orchards during periods far too cold for the honeybee, Andrenids and other small bees were very sensitive to wind movement; they hung to leeward, and as a breeze increased to a gentle wind they disappeared. Honeybees were only slightly affected by a breeze of sufficient velocity to stop the andrenids. Wild bees were more in evidence near uncultivated lands. Blowflies were extremely active on pear blossoms, particularly for several hours before a rain. They also appeared on the sunny sides of tree trunks and limbs, and fed freely upon the fluid oozing from blight infections, where no honeybees were found. Syrphid flies eviden fed more or less on the pollen, but the chief interest of flies in general was in nectar. - 8 - . . . Note the abundance of the honeybee as compared with the other insects. TABLE 2.— Comparison of insect visitors observed on apple, cherry, pear, and plum blossoms at Camino, Calif., during the seasons of 1932 and 1933 Insects Number of insects Percent of total visitors Honeybees Blowflies Small wild bees . Syrphid flies Bombyliid flies . Leaf-cutter bees Others Total 10,774 926 759 200 164 33 230 13,086 82.3 7.1 5.8 1.5 1.3 .2 1.8 100.0 Increased Areas under Cultivation Cultivation of the land destroys the nests of beneficial insects and discourages rehabitation. The 1940 census reports a decrease in farm wood lots (nesting sites) of over 53 million acres since 1910. Brittain, W. H. 1933. Apple pollination studies in the Annapolis Valley, N.S., Canada, 1928-1932. Canada Dept. Agr. Bui. 162, 198 pp. p. 92: Observations were made by Hooper (1929 and 1931) over several years on the numbers of various insects visiting apple blossoms, and the numbers added up. The district contained many cherry, apple and other fruit plantations and numbers of hive bees were kept. The land not in orchard was either ploughed land or sheep pasture, not very suitable for pollinating insects. The counts on apple were as follows: Hive bees 374 Bumble bees 37 Halicti, etc 21 Flies ,. 23 Beetles 104 Ants 51 Earwigs 3 Thrips 2 p. 93: Bumble bees are a variable quantity. They are numerous in the region of the North Mountain, and especially in certain seasons, as in 1930, were a decided factor in pollination of an orchard at Blomidon, but in 1931 were much less numerous. In 1932 there was an apparent increase at some points, but, taking the area as a v/hole, they - 9 - cannot be considered an important factor in apple pollination. There is cons ble testimony to the effect that the bumble bee population ;clined in t years . Formerly, it is said that they v common in more or less damp meadows where hand mowing had to be re- sorted to, but are now much less frequently found, especially in the Valley proper. Whether this is actually the case, and whether, if true, it is due to limitation of breeding places, poisoning, or some other factor, cannot now be determined. p. 96: Without pui u ng this subject further, it may be pointed out that roadside banks, pastures and dykes do not represent exactly wild conditions, but are the product of human activity. However, neither are such locations intensively cultivated. Cultivated land certain soil types, such as light sand or gravel, are not suited to i,nfi> which is one reason ...that rthe solitary bees are more numerous :\ and along the North Mountain, than they are at many points situated in the middle of the Valley.. p . 108: In 193?! tho number was less, corresponding to an ap- parent decrease in the, solitary, bee._faung,_ from all stations. This ob- servation may be correlated with a heavy mortality occurring among the solitary bees in the summer of 1931, apparently due to drowning in the nests following wet weather. Hutson, R. 1926. Relation of the honeybee to fruit pollination in New Jersey. N.J. Agr. Expt. Sta. Bui. 434, 32 pp. pp. 10-12: The difference in the number of insects present in the cultivated Triangle plot . . . practically surrounded by tilled land, and in the cultivated Starr planting situated beside overgr land is quite marked. Family Triangle Starr Chironomidae — midges 27 121 Bombidae — bumblebees 4 31 Syrphidae — syrphus flies 25 67 Scarabaeidae — beetles — 4 p. 27: It has been generally demonstrated that insects, es- pecially honeybees, are factors in the set of fruit. Another factor is the comparatively high state of cultivation obtaining in the orcharding districts, which destroys hibernating places. The conditions do not obtain in the cranberry bogs which are surrounded by overgrown land, as cranberries do not bloom until July, giving ample time for breeding. - 10 - p. 29: The number of species of insects acting as fruit pol- lenators in southern New Jersey is small; the number of individuals other than honeybees is small; the lack of pollenizers being most ser- ious in apple and pear orchards situated in cultured areas, less serious adjacent to uncultivated land, and not a problem at all on cranberry bogs, surrounded, as they are, with woodland, and blooming two months later than apple and pear. Honeybees and bumblebees are the most important insect polleni- zers in southern New Jersey. The ease with which honeybees can be supplied as needed is the deciding factor in making them the most dependable pollenizers. Johnston, S. "7. Pollination, an important factor in successful pear production. Mich. State Hort. Soc. Ann. Rpt. 1927: 196-199. p. 199: Bees or other suitable insects are therefore necessary for pollen transfer. While other insects carry pollen to some extent, the honeybee has no equal in this respect. Unfortunately, tame bees e been greatly reduced in numbers throughout the State by foul- brood, a very serious disease of bees, while the wild bees have been i;r::§il£_£ejincj>d__in numbers thro.ugh_the extermination of our forests and the thoughtless cutting; and robbing; of bee trees . Legasse, F. S. 1928. Proper pollination of fruit blossoms. Del. Univ. Agr. Ext. Bui. 15, 20 pp. p. 5: Poor sets of fruit have long been associated with rainy weather during the blossoming season. We have learned that this is due to the fact that honey bees, particularly the domesticated ones, do not fly extensively during rainy, cool, and windy weather, rather than to the effect of the rain on the blossoms themselves. This is another condition over which we have little control. The only possible r 5rn edy_ lies in the harboring of greater numbers of certain ..wild in- §2 "ts^such as the wild honey bee, which fly under woather conditions that cause the domesticated bee to cling; closely to the hive. However. the prevalent system of_ clean cultivation and cover crops, .furnishes n "-■nQStinKjplace for the wild bees avid is not conducive to their mul- tiplication in our orchards. Murneek, A. E. 1930. Fruit pollination. Mo. Agr. Expt. Sta. Bui. 283, 14 pp. p. 1: Almost all fruit grown in Missouri are pollinated by insects. Wind is no factor in fruit pollination. V/hen the orchard is small and there is a great deal of waste land in close proximity, enough wild bees, bumble bees and other insects may be present in the spring to be of benefit in pollination. But in a region where most of - 11 - the land is under cultivation, the common honeybee is the only insect to rely upon. They are the only pollenizer under the control of man. Murneek, A. E. 1937. Pollination and fruit setting. Mo. Agr. Expt. Sta. Bui. 379, 28 pp. p. 13: Of the various kinds of insects that visit flowers early in the spring, the common honeybee is by far in the majority. Moreover, it has been demonstrated in a convincing way that bees are of great value in pollination of apples, pears, cherries, plums and many other fruits. This is particularly true in sections where most of the ground has been put under cu Itivation with very little waste land left to harbor wild insects. Phillips, E. F. 1933. Insects collected on apple blossoms in western New York. Jour. Agr. Res. 46: 851-862. p. 861: It seems probable that the scarcity of wild insects on apple blossoms is due to a combination of factors incident to agriculture of the fruit districts. The relatively high land values tend to reduce waste land and wood lets and also tend to eliminate the wid a fence rows which are favored nesting places for some species . Cultivation reduces nesting and hibernating places, especially of sol- itary bees. Clean cultivation of orchards, where practiced, still fur- ther reduces the opportunities for the propagation of wild bees. It is possible that the efforts of fruit growers to control injurious insects in some degree serves to destroy individuals of those species which are beneficial. Beekeepers have observed that dusting destroys many honey- bees, and it is probably equally disastrous to solitary bees. Tysdal, H. M. 1340. Is tripping necessary for seed setting in alfalfa? Amer. Soc . Agron. Jour. 32: 570-585. p. 583: The most effective pollinators in this study have been Megachile and Nomia bees, several species of which have been observed working on alfalfa. Other conditions being favorable, it would appear that one of the most effective means of insuring a seed crop of alfalfa would be a supply of these small, relatively harmless, hard-working insects. It should, therefore, be sound agronomic prac- tice to encourage their presence in an alfalfa seed field. The writer has talked with alfalfa seed growers who have plowed through a large colony of these bees, which often make their home in the group 3 in some instances it has been known that such practices have destroyed the entire colony, or at least causod it to move . p. 584: Entomologists who have observed the alfalfa pollinating insect population in Nebraska for many years unhesitatingly state - 12 - that there are fewer colonies of Nomia species and fewer of Megachile species than formerly. It is possible that cultivation and settlement has disturbed the wild bees and thus reduced their number. Hence, it is suggested that a decrease in the population of these beneficial insects, together with a possible increase in harmful insects, may be an explanation for the uncertainty in alfalfa seed production in formerly good seed-producing areas. Concentrated Plantings id pollinating insects apparently do not range widely for food, and since they do not store an appreciable amount of food, concentrated plantings of one crop are not favorable for their development. Brittain, W. H. 1933. Apple pollination studies in the Annapolis Valley, N.S., Canada, 1928-1932. Canada Dept. Agr. Bui, 162, 198 pp. p. 9: It should be emphasized, however, that a few colonies of bees placed in an orchard surrounded by large acreages devoid of boes is of little or no value. In such situations it may be necessary; to.haya.a concentration of from 35 to 50 colonies in .order to ensure the, pollination of the particular orchard in which the bees are placed. In districts where beekeeping is general, however, and neigh- bouring orchards are similarly supplied, one colony to the acre or even cne colony to four acres may be sufficient. Owing to the many factors involved more exact figures cannot be given. It must suffice to point out that the provision, of. _as many colonies as practicable is a_,jo T1E2 of insurance against unfavourable weather, and a ,oarcity of wild pollinators, since it is only the hive bees that can be increased in numbers at will and placed where needed in the orchards. !ji fortunately, at the present time, there is no adequate local supply_;_ ±:!2i22£i^i!2§. in beekeeping and tho danger of poisoning prevents __many •qsi adopting this practice who would otherwise do so . Kootman, D. H. 1930. The importance of pollination and the honey-bee in fruit yields. N.Y. State Kort. Soc. Proc. 1930: 49-58. The location and size of the individual orchard are apparently the factors that determine whether or not bees are needed. Orchards not too large in siz9 with varieties well mixed, located near woods, 3 or uncultivated land where wild insects can winter over in large numbers, usually set a satisfactory _crop_without additional bees. With the conditions that exist in commercial fruit sections where whole communities are engaged in fruit growing and where or- tave been planted by the square mile the wild insects, are ' I ly, inadequate to pollinate effectively the vast expanse of bloom . It is in these locations especially that commercial fruit growers are largely dependent upon the honeybee — the only insect admirably adapted for pollinating fruit bloom that can be readily controlled by man. - 13 - Kearney, T. H. 1923. Self-fertilization and cross-fertilization in Pima cotton. U.S. Dept. Agr. Dept. Bui. 1134, 68 pp. p. 49: Observation in Arizona has shown that the number of efficient pollinating insects differs greatly in different localities. 2/ Bees and other active pollinators are normally abundant among the cotton Flowers at Sacaton throughout the summer, and the entire surface of the stigmas is almost invariably well covered with pollen soon after the corolla has opened. On the other hand, observations in the Salt River Valley, at distances of 25 to 40 miles from Sacaton, have shown that insect pollination of cotton there is often much less rapid • and complete. The probable explanation is that in recent years an extensive and almost continuous acreage has bsen planted to cotton, and the insect population is not large enough to insure thorough pollin- ation of- all the flowers. Thus, en July 13, 1919, in a field situated near Tempe in the heart of the cotton-growing district, no pollen grains were observed upon the extrastaminal portion of the stigmas at 9 a.m. and very few at 10 a.m. Late in the afternoon of July 20, 1920, inspection of the - same field showed- the extrastaminal portion of the stigmas to be free from pollen in most of the flowers, while the remaining bore only a few insect-transported grains. None of the flowers examined showed thorough pollination of the whole stigmatic surface.- Two other cen- trally located fields, one at Phoenix and one near Tempe, which were examined at 5 p.m. on August 5 and at 4 p.m. on August 6, showed similarly deficient pollination. On the other hand, in fields situated on the outskirts of the valley, at Litchfield and at Goodyear, which were examined at noon on the same days, bees and other pollinators were abundant, and the stigmas of the cotton flowers were found to be well covered with pollen, p. 50: In the mean number of seeds per 100 flowers, a value which integrates the percentage of bolls matured and the mean number of seeds per boll, the increase due to artificial pollination amounted to 32 per cent, indicating that a substantially greater crop both of s 2_: af fiber m igh t be expected jf_bees were abundant in the Salt River Valley cotton fields during the blossoming period . 2/ A pronounced difference in the abundance of pollinating insects at different localities in Arizona was noted by Cook, McLachlan, and Meade. "At the tj ce of our visits to the fields at Yuma and Sacaton there notable difference in the activity of the insects at the two places, Several species of large .re industriously visiting the flowers at Yuma in September were not seen at all at Sacaton." - 14 - Luce, W. A., and Morris, 0. M. 1923. Pollination of deciduous fruits. Wash. Agr. Expt. Sta. Bui. 223, 22 pp. p. 21: Observations made at Wenatchee in the spring of 1926 and 1927 developed the fact that there are relatively few insects visiting the apple blossom in many orchards. These examinations showed that there was a lack of insect activity necessary tc perform the cross-pollinizing in commercial orchards. In orchards where there were still plenty of trees of several different varieties the failure of a crop was apparently due to lack of insect activity at blossom time . Orchards nearest the foot hills or __open country produced the heaviest set of _fruit_. The native bees and, insects came in abundance Yoia the rocky or hilly ground near these _ orchards . This condition has been knovm to prevail in many local districts for several differ- ent years. Where wild bees and other insects are abundant, a minimum amount of help is needed from the honey bee, but in the large closely giant e d comma r c ia 1 sect ions, where_there are__very_few wild, bees _._and other insects visiting the blossoms, more honey bees should be pro- vided. RailrFence Elimination and Heavy Grazing Rail fences constitute ideal nesting places for many species of pollinating insects. The replacement of rail by wire fences has destroyed such nesting places, for wire fences permit clean, close cultivation. The increase in the output of wire fences and their relative cheapness has facilitated the use of stock for cleaning up fence rows and out-of-the way patches of land which would otherwise harbor pollinating insects. It is an axiom in beekeeping that bees starve on sheep ranges. The sheep trample the ground and eat the vegetation into the ground, leaving few flowering plants. There has been an increase of more than 4 million head of sheep on farms since 1910. The practice of pasturing sheep in woodlands is detrimental to the propagation of wild pollinating insects. Sims, I. H., Munns, E. N., and Auten, J. T. 1938. Management of forest soils. U. S. Dept. Agr. Yearbook (Soils and Men) 1938: 737-750. p. 744: The number of livestock grazing the farm woods in the Central States is estimated to be five times the actual carrying capacity and is maintained largely by supplementary feeding of crop feeds. - 15 - Spencer, D. A., and Potts, C. G. 1933. Sheep raising in U. S. has changed greatly since pioneer period. U. S. Dept. Agr. Yearbook 1933: 264-273. p. 264: Sheep are also tensively in the grass-produc- ing areas of the Eastern and Central S cularly in rolling and hilly sections. Since sheep are_fond of a great variety of weeds and underbrush which cattle and horses do not relish, they are useful in keeping fields and fence corners clean and in utilizing forage not so well adapted to other livestock. p. 267: Except where flocks are kept to produce purebred stock, special crops are seldom grown for the sheep, which are generally turned .onto pasture as s oon as the grass begins to grow in the spring and remain there until the crops have been harvested, when they are usually given the run of the fields to graze and to clean up the weeds, and remain there until snow falls. They are then carried through the winter on hay and some of the unsalable roughage, with little or no grain. Forest, Brush, and Grass Fires Forest, brush, and grass fires destroy all kinds of wild life, including pollinating insects-. The practice of burning fence rows, rail- road right-of-ways, pastures, etc., is highly detrimental to wild pollin- ating insects, most of which nest in or near the ground. Sirns, I. H., Munns, E. N. , and Auten, J. T. 1938 Management of forest soils. U. S. Dept. Agr. Yearbook (Soils and Men) 1938: 737-750. p. 741: Heavy cutting has commonly been followed by fire, and examples of serious soil deterioration due to this combination of treatments can be found in practically every forest region of the country. Some 60 million acres of land have been so completely dev- astated by this combination that they are unlikely to reforest naturally and must be planted. total is being swelled currently by the addition of 850,000 acres each year, three- fourths of which is land formerly occupied by conifer stands. When cut-over land is burned the fire accomplishes in minutes the degree of litter removal that would be achieved naturally only after several years... This sudden removal of the litter and its living population set- otion a chain of events leading directly to deterioration or loss of the soil . p. 743: Extreme soil temperatures frequently develop during the great conflagrations and humus in the upper horizons is oxidized immediately. The mineral soil has much the same appearance as samples ignited in a furnace. Accumulations of he debris bu rn intensity that the soil is sterilized for years. - 16 - The Automobile and Paved Roads Fast-traveling automobiles kill large numbers of pollinating insects. For every slow, awkward female bumblebee killed in the spring there is one less nest of pollinating insects later in the year. Improved, well-kept roads offer little refuge for wild pollinating insects. Pickles, W. 1942. Animal mortality on three miles of Yorkshire roads. Ecol. 11: 37-43. Jour. Anim. p. 38: As with the Coleoptera, the Hymenoptera, chiefly bees, have met their deaths either by being crushed by the wheels of the vehicles, or in the manner indicated above. p. 40: A busy road passing through a country district has a big effect on the animal life in its vicinity. Throughout the year 1938, the total number of animals [insects] killed on the 3 miles of road under observation was 687... This is 229 per mile; of which 113.3 were Hymenoptera. pp. 41-42: Altogether, there were 42 different species of animals killed on the reads. [The Hymenoptera included were as follows:] Bombus terrestris L. B. lapidarius L. B, rauscorum L. B, agrorum F. B. ruderatus F. Apis mellifera L. Colletes succinata L, Andrena armata Gmel . Vespula vulgaris L. V. germanica F. Poisoning from Insecticides Hundreds of colonies of honeybees are killed each year by arsenical sprays and dusts. Often the losses occur long after the insecticides have been applied, when brood is fed stored poisoned pollen. Under such condi- tions bees gradually dwindle and die, and often the owner is not aware of the true cause. At one time poisoning of honeybees was confined largely to the fruit- blossoming period, when bees took poison from open blossoms, but now the poisoning continues throughout most the summer because many cover sprays are applied to control injurious insects, particularly the codling moth. Sprays and dusts falling on cover crops in orchards kill both honeybees and native bees. From the knowledge of the habits of wild pollinating insects and the fact that the queens obtain their food directly from flowers, they would appear to be even more susceptible to insecticides than honeybees, since the queen's food is not nectar and pollen but royal jelly. Brittain made obser- vations on this point, but came to no definite conclusions as to the over-all - 17 - effect of the use of insecticides on wild pollinating insects. He did find, however, lethal amounts of arsenic in pollen in the nests of wild bees. VALUE OF THE HONEYBEE IN POLLINATING CROPS On the following pages will be found a few selected references to the value of the honeybee in pollinating crops, as mentioned in articles by recognized authorities in horticulture and agronomy. Dietz, H. F. 1925. Pollination and the honey bee. Ind. Conserv. Comn. Pub. 52, 20 pp. pp. 19-20: One thing is certain. The honeybee represents the highest poiri '-_beaji__r3acj:ted ift the insect world as a flower gjllinator. Its own existence in both the, larval and_ adult stage are deEer^s^i-ih^either^gjit^i-lilJilxCtdr^ T;ie._habit_s that it possesses of - - ■'-"•g. hiai ■:■["' flower at a,_tim,: make it. a i more effective pollina- tor than an insect, that visits all flowers promiscuously. . . And finally the honeybee is the only one of the insect pollina- tors that man has under his control or domesticated, so to speak. Alj the rest are .subject to all the isitudes of nature, including unfavorable weather conditions, food shortage, which cannot be sup- plied, and the Is of natural enemies, including Man. Man through his va often as and mult I .ous activities, is the atest disl u '_ ' _th i ^ural order of things, and what he does he must pay the pri ;e for in one manner or another . Ho we ye r , _by_ s tudy.ir, g the ways of nature he often corrects his errors and when he needs a general flower pollinator he has but to try the honeybee . Vansell, G. H., and deOng, E. R. 1925. A survey of beekeeping in California and the honeybee as pollini- zer. Calif. Agr. Expt. Sta. Cir. 297, 22 pp. pp. 17-18; Of all the insects that visit flowers, bees are the best adapted by the structure of the body to act as carriers of ■ ien. The body and legs are covered with heavy, stiff hairs which are branched or featherlike. These catch and hold the pollen grains, until hey are brushed into a "pollen basket" on the hind leg. In this carrier the load of pollen is transported to the hive. However, all bees are not of equal value as pollinizers as some of them do not visit all types of flowers. The honeybee and the bumblebee, however, visit almost all flowers with little restriction except that they evidently confine themselves to a single species on any one trip. We have many native species of bees such as bumblebees, car- penter bee, leaf cutters and others, but only in rare instances are any of these active during the early spring and then only in very restricted numbers. - 18 - The bumblebee is one of the earliest of the native bees to feed in the spring, but the entire colony, except the queen, perishes during the winter. In the spring the whole responsibility of rebuilding the colony devolves upon the queen. She lays and incubates the eggs, seven to sixteen in number, feeds the newly hatched larvae and only after the first brood matures can she give her strength entirely to brood rearing. By fall the colony may have grown to a size of from one to five hundred individuals. Certain of the mining bees, Halictus, which nest in certain cliffs, have one or two generations a year. The spring genera- tion consists of hibernating, fertilized females which give rise to a summer generation. The leaf-cutting bee, Megachile spp., apparently has but one generation a year and includes but a small number of indi- viduals. The carpenter-bee, Ceratina doola, has two broods a year v/hich are very restricted in numbers. These examples are typical of the life history of our common native species of bees thathave from one to five or six brood cylces annually, while the number of individuals range from a score to a few hundred. Comparing this with the honeybee's record of from twelve to fifteen brood cycles a year, all the descendants of a single queen , which may reach a hundred thousand bees annually, or more, we realize the wonderful reproductive powers of this insect. It should also be noted that instead of the death of all the workers, the winter's mor- tality among honey bees is usually very slight. From five hundred to sixty thousand may be present in a single colony at the close of winter and two or more brood cycles may be reared in the spring before many of the fruit trees bloom. Fruit Crops trees fail to bear. U.S. Dept. Agr. Leaflet 172, ild, H. P. 1939. Why fruit 5 pp. pp. 3-4: Self-sterility is very common. It occurs in many varieties of apples, most varieties of pears, probably in all varieties of sweet cherries, in most if not all varieties of the native and Japanese plums, and in some varieties of European or domestic plums and prunes. Sour cherries are considered largely self-fertile, al- though there is some evidence of partial self-sterility. Most peach varieties are self-fertile; the J. H. Hale and June Siberia (Mikado) are notable exceptions, as they require cross-pollination. Sterility in plums, cherries, and perhaps other fruits may sometimes be due to deformed or imperfect pistils. Some grape varieties must be cross- pollinated in order to be fruitful. There is every conceivable degree of self-sterility, from one extreme where no fruit sets without cross-pollination to that where it - 19 - is go slight as not to be a serious factor in fruit production. The opinion is commonly held that even the varieties considered to be self-f in a high degree will set a better crop of fruit if ■lination occurs. With self-sterility prevailing to so large extent in common fruit varieties, the relation of weather conditions ; '^I-Ti to the greatest activity of honeybees becomes readily appar- . since it is on them that the fruit grower must depend very large- ly for the cross-pollination of his fruits. When self-sterile varieties are planted and there are no other tre es of different varieties of the same kind growing near enough to insure the passing of bees from one to the other, it will be found that trees blossom but do not set._fruit. When the tree to be cross-pollinated is in bloom secure some blossoming branches from a tree of another variety of the same kind of fruit and place them in a pail or other water container in the top of the tree. The bees, visiting the trees, will also visit the blossoms on the branches and will thereby transfer the pollen as they revisit the blossoms on the tree. Murneek, A. E. 1930. Fruit pollination. Mo. Agr. Expt . Sta. Bui. 283, 12 pp. p. 1: With proper care bees winter over in large numbers and are very active in the spring. They are especially well adapted to carry pollen. Their bodies and legs are covered with hairs to which the pollen grains adhere in large numbers. Moreover, the honeybee visits only one kind of flower, like the apple or the peach, at a time . Thus they are very effective agents in cross-pollination . P • 9 : It has been demonstrated in many orchards in a convinc- ing way that bees _ g r^at vai-p for the pollination of apples, sour cherries, and other fruits. If the orchardist does not keep his own bees and there are none in the neighborhood, then most certainly it will pay to secure several hives. Philp, G. L., and Vansell, G. H. 1932. Pollination of deciduous fruits by bees. Calif. Agr. Col. Ext. Cir, 62, 27 pp. p. 4: The fruit grower has a pollination problem with almonds, cherries, plums and prunes, apples, pears, and berries . In' general, apricots, peaches, and walnuts set well with their own pollen and hence present no difficulties from this standpoint. The J. H. Kale peach, however, is self-unfruitful and must be interplanted with some other variety. Recent studies indicate that some varieties of walnuts in certain years do not mature the staminate and pistillate flowers at the same time and therefore, under these conditions, cannot pollinate themselves. - 20 - p. 5: Bees are the most important insects for this work. The grower should therefore have plenty of bees in the orchard during the blossoming period. [Honeybees are rented for the pollination of almonds, apples, avo- cados, cranberries, pears, plums, prunes and cherries, as well as cucumbers and alsike clover.] Almond Tufts, W. P., and Philp, Guy L. 1922. Almond pollination. Calif. Agr. Expt. Sta. Bui. 343, 35 pp. p. 24: Pollenizing agencies, such as the honey bee, are neces- sary to the set of a good crop of fruit. One colony of honey bees should be provided for each acre of orchard. Crane, H. L., and Reed, C. A. 1937. Nut breeding. U.S. Dept. Agr. Yearbook 1937: 827-889. p. 872: The pollen of almond and tung trees is carried by insects. Apple Auchter, E. C. 1924. The importance of proper pollination in fruit yields. N. J. State Hort. Soc. Proc. 1S24: 133-142. pp. 140-141: The value of bees in pollination. The carrying of pollen from one variety to another is accomplished by wind and bees. It has been found, however, that pollen is carried only very short distances by wind, but that bees play a very important part in carrying the pollen. In crossing into the blossoms to get the nectar, their bodies become dusted with the pollen. This pollen is then left on the stigmas of other blossoms when they are visited. In California the investi- gators are recommending one hive of bees per acre for pollination purposes. A few years ago, the writer helped to conduct a special test to prove the value of cross-pollination and bees in a bearing Rome Beauty orchard in West Virginia. This orchard consisted of approximately twenty acres and was planted at quite a distance from any other or- chards. Although it blossomed well each year, the set was always very light. During the blossoming time for two years bees were placed under sixteen trees in the center of the orchard and blossoming limbs of other varieties were secured and placed in pails of water, which were hung in the Rome Beauty trees. The bees worked back and forth through these - 21 - blossoms and an excellent set was secured each 5rear_0n__the.se sixteen trees . The, rest of the orchard, at some distance from the bees, set only a light crop. A similar test conducted in 1922 in a bearing Stayman Winesap orchard in Maryland where bees were placed in the orchard, together with blossoming branches of the York Imperial variety in- pails of water, resulted in a fair crop of fruit being set, even though the season. w:is unfavorable for pollination purposes due to some frosts and cold windy weather . In previous years, without bees or the York Imperial blos- soms, very little fruit "set" although there were plenty of Stayman blossoms and the weather was favorable. In 1923 with good pollination weather and Grimes blossoms placed about the bee hives, a good set of fruit was obtained in this orchard. In some special tests at the Experiment Station in 1923, two trees, one a Grimes and one a Stayman Winesap, 40 feet apart, were inclosed in a large muslin frame 14 feet wide, 14 feet high, and 55 feet long. A muslin partition was built through the center of the tent (long ways) so that one-half of each tree was on one side of the partition and one-half of each tree was on the other side. Bees were placed in one side of the tent, so that they could fly back and forth between the halves of the Grimes and Stayman Winesap trees. No bees were placed in the other side of the tent. In the side in which bees e placed, fruit set on the halves of both . the Stayman Winesap and Grimes trees. In the other side of the tent without bees, no fruit set on the halves of. the same Stayman Winesap tree, although the G£ig6s-^_bgiHg_a_self- fertile . variety... did set some fruit . Apparently in the one-half of the tent, the_Grimes pollen was carried by the, bees to the Stayman Winesap, giving a set, while in the other half, the Grimes pollen did not reach the Stayman blossoms. Another test of the value of bees was indicated in some experi- ments carried on at the College in 1923. Two hundred and fifty blossoms each of Baldwin, Lawver, Stayman Winesap and Kinnaird were emasculated and left unbagged or open to cross-pollination. Apparently, because all of the petals had been removed by emasculation, the bees were not attracted to these blossoms. As a result, not a blossom on any of the emasculated blooms "set." Other unemasculated blossoms (with their petals expanded) on the same limbs were apparently visited by the bees so that cross-pollination took place. In these cases 21.4 per cent of the Lawver blossoms, 6.4 per cent of the Kinnaird, 15.8 per cent of the Baldwin, and 5.3 per. cent of the Stayman Winesap "set" fruit. From the above experiments , it can be seen how important it is for orchardists_.to have several hives of bees scattered through their orchards . The last experiment_also suggests that a great many 1 - 22 - might be killed if poisonous sprays are used when the petals of the blossoms are showing. MacDaniels, L. H. , and Heinicke, A. J. 1929. Pollination and other factors affecting the set of fruit, with special reference to the apple. N. Y. (Cornell) Agr. Expt. Sta. Bui. 497, 47 pp. pp. 4-5: The flowers of the apple and of most of our fruit plants are adapted by their structure to insect pollination. The showy petals, the odor, and the nectar-secreting glands have the function of attracting insects which carry the pollen from flower to flower. The pollen itself is of the sticky type that adheres to the hairy coat of insects which visit the blossoms . . . rather than of the light dry type that is adapted to wind dissemination. When it is appreciated that it would take approximately 400 apple-pollen grains placed side by side to reach from one end of a bee to the other, and that the number carried by _a_single bee might easily approximate 100,000, some idea of the possible effectiveness of insect pollination can be gained. Overholser, E. L. 1927. Apple pollination studies in California. Calif. Agr. Expt. Sta. Bui. 426, 17 pp. p. 15: The use of bees as a means of effecting pollination in an apple orchard greatly increased the set of fruit when contrasted with the normal set. Cross-pollination increased the set of fruit, even with self- fruitful varieties like the Yellow Newtown. Swinson, C. R. , Weaver, F. P., Dadisman, A. J., Vernon, J. J., Gould, H. P., and Lincer, J. B. 1927. Factors influencing the yield of apples in the Cumberland-Shenan- doah region of Pennsylvania, Virginia, West Virginia. U.S. Dept. Agr. Tech. Bui. 54, 25 pp. p. 21: A number of growers attributed low yields to failure of fruit to set. It was commonly observed that the low yields of the Winesap and varieties of the Winesap family were ascribed to this factor. These varieties are largely self-sterile and must be cross- pollinated by some other variety. Self-sterile varieties should not be planted in solid blocks or isolated from other orchards. Where self- sterile varieties have been so planted the results may be improved by top-working every fourth or fifth tree in every fourth or fifth row with some variety that is a good cross-pollinizer. Bees_are essential in any orchard and are effective in securing pollination even during cold, wet seasons. - 23 - Avocado Stout, A. B. 1933. The pollination of avocados. Fla. Agr. Expt. Sta. Bui. 257, 44 pp. p. 42: It is without doubt advisable (1) to interplant avocados on the basis of the;u flower behavior (2) to supply bees in abundance to effect pollination. Traub, H. P.. Pomeroy, C. S., Robinson, T. P., and Aldrich, W. W. 1941. Avocado production in the United States. U. S. Dept. Agr. Cir. 620, 28 pp. p. 3: With some varieties, as Fuerte, there is sufficient overlap of the two sets of flowers to render them self-fertile; with o^yier >j&r4%tjies, ". siu'i'Lcient percent-; ■ single-cycle flowers (completing their anthesis in one op: are p render self-pel ination easy of accomplishment, the only requirement in each case being the activity of bees or other insects ... Keeping bees in or about the orchard is also considered a wise larovis U n during; the blooming period . Observations indicate that pol- len is carried considerable distances by bees and doubtless by other flying insects. Blackberry Darrow, G. M. 1937. Blackberry and raspberry improvement. U.S. Dept. Agr. Yearbook 1937: 496-533. p. 498: Normally the wild blackberries of the East are entirely or nearly self- sterile, and those of the Pacific coast have male and ale organs on separate plants. All need cross_-pollination. In the clearings and pastures bees and other insects have . crossed the black- berry species for the last 100 to 300 years. Blueberry and Huckleberry Merrill. T. A. f 1936. Pollination of the highbush blueberry. Lch. Agr. Expt. Sta. Tech. Bui. 151, 34 pp. p. 33: Of much greater importance than self or cross-pollina- tion, though it receives little space in this report, is the need of insuring some (any) sort of pollination. Mechanical aid is absolutely necessary to a good set, from self as well as from cross-pollination. \iBaaeoen qib ,aeed ^enori cj3 riouo ,~9iofl9^.o ^il^inx-.-.u . .. .H 3u;.7iblR-be3S__and hjaevjoees play a xgJffl HMteb86ji t-J3LJ;jiQklu.$berr; pollination. - 24 - Phipps, C. R. 1930. Blueberry and huckleberry insects. Maine Agr. Expt. Sta. Bui. 356, pp. 107-232. p. 116: In conclusion, then, the investigations thus far have shown: (1) that various species of insects, especially_honey-bees, bumble-bees and other bees^. collect blueberry pollen: (2) that such in- sects undoubtedly exert a marked influence on blueberry pollination since their exclusion affects yields so strikingly. Cherry Lagasse, F. S. 192S. Proper pollination of fruit blossoms. Del. Univ. Agr. Ext. Bui. 15, 20 pp. p. 10: The experimental results obtained in different sections of the country on the sour cherry with respect to its self-fertility do not entirely agree. The majority of evidence, however, indicates that most varieties will set commercial crops thru the use of their own pollen. Shoemaker ... has recently shown that the set of Mont- morency is increased under Ohio conditions by the use of early Richmond pollen, but it is doubtful whether the increased set will compensate for the space occupied by the trees of the inferior pollinating variety. Interplanting of several varieties, better cultural practices, and the placement of be_e_g_ in the_sou.r_cherry orchard is recommended for in- creasing; the set of fruit . Schuster, C. E. 1925. Pollination and growing of the cherry. Oreg. Agr. Expt. Sta. Bui. 212, 40 pp. p. 23: With fruit so dependent upon cross-pollination as are cherries, the agents responsible for this transfer of pollen need to be considered. The number and presence of wild insects can be controlled very little, but the honey-bee can be controlled to a great extent. It is becoming the practice for cherry growers either to keep their own bees or to hire stands of bees during the blooming season. One hive to one or two acres of cherries is sufficient if the stands of bees are strong. The sour cherry may be self-sterile, self- fertile, or partly self-fertile, depending on the variety. Tufts, W. P., and Philp, G. L. 1925. Pollination of the sweet cherry. Calif. Agr. Expt. Sta. Bui. 385, 28 pp. p. 26: Pollinizing agencies, such as honey bees, are necessary to set a good fruit crop. orchard, - 25 - At least one stand of bees should be provided for each acre of Cranberry Darro.v, G. M., Franklin, H. J., and Malde, 0. G. 1924. Establishing cranberry fields. U. S. Dept . Agr. Farmers' Bui. 1400, 37 pp. pp. 9-10: Results of investigations by the Massachusetts Agri- cultural Experiment Station indicate that in that State cranberry blossoms are pollinated by bees. Bumblebees and honey-bees seem to be the chief agents of pollination . As the former are not always abun- dant many growers keop small apiaries. Bees are not common in the cranberry region of Wisconsin, and experiments and observations by representatives of the Wisconsin Agricultural Experiment Station indicate that though they help in pollination they are not necessary in that State under normal con- ditions. The cranberry blossoms there seem to be practically self- fertile. After the flower bud opens ... the pistil grows past the anthers and may be fertilized then or later as the flower is jostled by the wind. Even in Wisconsin bees may be of great value in hasten- ing pollination, thus insuring uniformity in the time of setting and maturing the_ fruit. Without insect aid the pollination is apt to extend over a long; period and the fruit likely to mature unevenly. Cucumber Beattie, W. R. 1942. Cucumber growing. U.S. Dept. Agr. Farmers' Bui. 1563, 25 pp. pp. 12.-13: Pollination, or the setting of fruit, on cucumber vines is dependent upon some outside agency such as bees. Two kinds of flowers are found on every fruiting cucumber plant — the male ones . . . which supply the pollen, and the female ones... which produce the cucumbers. They can be readily distinguished, as the female flower is borne on the outer end of the little cucumber. Usually the male flowers appear in great abundance in advance of the female flowers, which leads to the erroneous notion that the cucumbers are failing to set fruit. Later, the female flowers appear, and fruit is formed. Cucum- bers grown in the field are pollina ted by either tame or wild bees from the neighborhood. Under favorable conditions, cucumbers grown in frames may be pollinated by natural agencies, but the sash-cucumber growers of the Norfolk district provide hives of bees near their frames when the cucumbers are set ting, in order to insure perfect pol- lination . Without proper pollination the cucumbers are deformed, or at least_ a__considerable1 percentage of nubbins are produced. In local- ities where bees are_ scar ce_ it is advisable for the growers c f c u cum- bers in fields to keep bees, in order to insure pollination. sTE PLANT BOA*" - 26 - Gooseberry Hooper, C. H. 1939. Hive bees in relation to commercial fruit production. Southeast. Agr. Col. Jour. 44: 103-108, illus. p. 106: There is an opinion that blossoms that have been pollinated resist frost better than those that have not been pollin- ated ... In England a Cambridgeshire grower who had a large acreage of gooseberries and _had hives of bees placed _among them, in a year in which frost damaged his neighbours^ crops, had a good crop which he attributed to his bees. Grape V Fletcher, S. W. 1941. Pollination. Standard cyclopedia of horticulture, by L. H. Bailey, v. 3, pp. 2734-2737. New York. p. 273S: Of one hundred and forty-five varieties of grapes tested by Beach, thirty-one were self-fertile, forty-one self-sterile, and seventy-three uncertain. Snyder, E. 1937. Grape development and improvement. U.S. Dept. Agr. Yearbook 1937: 631-6S4. pp. 639-40: The blossoms of Vitis are arranged in a pyramidal, loosely branched cluster known as a panicle. In the wild state some vines may bear only male or staminate flowers, while others bear perfect or hermaphrodite flowers that have both stamens and pistils. American native species bear male flowers and hermaphrodite flowers on separate vines, while most European vines of Vitis vinifera bear only hermaphrodite flowers. The hermaphrodite blossoms range from flowers having reflexed, very poorly developed stamens ... to perfect flowers with upright stamens . . . Varieties with reflexed stamens usually do not set fruit, or set only very loose clusters, unless they are cross-pollinated, either naturally or artificially. The pollen grains are deposited on the stigma through natural or artificial means. Dearing, C. 1938. Muscadine grapes. U.S. Dept. Agr. Farmers' Bui. 1785, 36 pp. p. 17: The pollen is carried from the male to the pistillate flowers almost entirely by insects. - 27 - While the honeybee is a less-effective pollinating insect for muscadine than for fruits with sticky pollen, such as apples, it appears_to_have sufficient value to_warrant placing stands of bees in large vineyards during the blossoming; season- Muskmelon Beattie, W. R. 1S26. Muskmelons. U.S. Dept . Agr. Farmers' Bui. 1468, 38 pp. p. 21: Growers frequently inquire why the early blossoms on their muskmeions do not set fruit. Muskmelon blossoms are of two kinds, staminate and pistillate, or male and female. Following the natural tendency of all vine crops, a large number of male blossoms appear in advance of the vines to set fruit. At the base of the pistillate or female blossom is located the small embryonic melon formed before the blossom opened, and it is necessary that the pollen from the male flower be transferred by bees or other insects to the female flower. Where melo ns are grown in greenhouses or in closed frames it is essential that provision be made for the entrance of bees in order that the pollen be transferred. Peach and Nectarine Cullinan, F. P. 1937. Improvement of stone fruits. U.S. Dept. Agr. Yearbook 1937: 665-748. p. 675: The nectarine was formerly thought to be a different species from the peach. It is now known that the nectarine is simply a smooth-skin peach. The trees differ in no respect from the peach, and it is impossible to tell a peach tree from a nectarine tree. p. 595: Most varieties of peaches are self-fruitful. Occasion- ally failure to produce crops may be due to pollen sterility, which is exhibited in a few commercial varieties, such as J . H. Hale, Halberta, Candoka, Mikado, and Chinese Cling. Marshall, R. E., Johnston, Stanley, Hootman, H. D., and Wells, H. M. 1929. Pollination of orchard fruits in Michigan. Mich. Agr. Expt . Sta. Spec. Bui, 188, 38 pp. p. 29: A J. H. Hale psach orchard favorably located on the Friday Bros. Farm near Coloma and containing a few scattering trees of other varieties had produced but a few fruits since planting in 1917. When it was learned that this variety was self-sterile, South Haven and Elberta trees were p \ in the vacancies as pollinizers for the J. H. Hale. In spite of this provision the orchard produced less than 10 bushels of peaches in 1926. Before the succeeding blos- soming period.. 20 colonies of bees were 1 in the orchard and it produced the first crop of fruit in 11 years. - 28 - Pear Kinman, C. F., and Magness, J. R. 1940. Pear growing in the Pacific Coast States. U.S. Dept. Agr. Farmers' Bui. 1739, 38 pp. p. 24: That cross-pollination is advantageous to setting fruit of practically all varieties is now generally conceded. Provisions for cross-pollination should be made, notwithstanding the fact that such varieties as Bartlett, Anjou, and others may, under favorable conditions, set fair crops when planted alone. One tree is considered sufficient to pollinize eight others if bees are provided to carry the pollen. Tufts, W. P., and Philp, G. L. 1923. Pear pollination. Calif. Agr. Expt. Sta. Bui. 373, 36 pp. p. 35: Pear fruits resulting from cross-pollination do not appear to exhibit the same tendency to fall after the June drop as do those resulting from self-pollination. Pollinating agencies such as honey bees are necessary to set a good crop of fruit. Persimmon, Native Fletcher, W. F. 1942. The native persimmon. U. S. Dept. Agr. Farmers' Bui. 685, 22 pp. pp. 3-4: The trees are generally dioecious; that is, the pollen-bearing and fruit-producing flowers are borne on separate trees. The pistillate or fruit-producing flowers are borne singly, whereas the staminate or pollen-bearing flowers are generally produced in threes. The pollen is very light and powdery, and, although it is g9nerally_distributed by bees that frequent the trees in great numbers during blossoming time, it can also be carried to great distances by the wind. Plum and Prune • Hendrickson, A. H. 1918. The common honey bee as an agent in prune pollination. Calif. Agr. Expt. Sta. Bui. 291, pp. 215-236. p. 236: The results of the two seasons' work seem to warrant the following conclusions: Both the French and Imperial _ prunes may be aided in setting fruit by the use of bees in the orchard during the blossoming period , provided the trees are in a normal, healthy condition. - 29 - The absence of bees in the orchard may mean a low percentage of set with both of these varieties. Hendrickson, A. H. 1922. Further experiments in plum pollination. Calif. Agr. Expt. Sta. Bui. 352, pp. 247-266. p. 266: The presence of honey bees materially aided in setting heavy crops on the following combinations of varieties: Formosa and Wickson; Beauty and Santa Rosa; Diamond and Grand Duke. Observe. Lions, furthermore, showed that many other combinations were also benefited by these insects. Hendrickson, A. H. 1919. Plum pollination. Calif. Agr. Expt. Sta. Bui. 310, pp. 1-28. p. 27: A comparison over a number of years between trees where there was an abundance of bees flying and trees where bees were scarce, emphasized the desirability of having bees in the orchard. Even self- fertile varieties were immensely benefited by the presence of bees as an agency for distributing pollen. Kinman, C. F. 1931. Plum and prune growing in the Pacific States. U. S. Dept. Agr. Farmers' Bui. 1372, 57 pp. p . 25 : The presence of bees in the plum orchard at blossoming time has been_demonstrated to be almost an economic necessity. . . . Poor crops or perhaps failures may be expected of self-sterile varieties where no bees are present, and even with_ self- fertile varieties the presence of bees has caused a decided increase in the crop. Strawberry Darrow, G. M. 1937. Strawberry improvement. U. S. Dept. Agr. Yearbook 1937: 445-495. p. 455: Pollen is carried by bees and other insects, but it is also thrown out of the stamens as the anthers crack open ... or it is jarred out and blown by the wind and falls on the pistils. A variety having perfect or hermaphrodite flowers can produce fruit when planted by itself, but one with pistillate flowers cannot set fruit unless p;rfestrf lowered plants _are nearby to furnish pollen through the agency of bees or other inserts. Tung. See Almond. Watermelon Goff, C. C. 1937. Importance of bees in the production of watermelons. Fla. Ent. 20(2): 30-31. - 30 - From these observations it is quite evident that the size of the melon crop may be greatly influenced by the bees. Observations in Florida and elsewhere show that certain days are favorable for setting melons while a very poor set will occur on other days, due to weather conditions. If the favorable days are few and the supply of bees small, the yield may be small, It is therefore important_that a good set be_obtained from the earlier flowers and to Insure this an adequate supply of bees should be present. Thus, in certain areas at least, the earliness and size of yield may be increased by keeping honeybees near the field during the flowering season. In large fields, the best results should be obtained by having a hive near the center of the field. Seed Crops Alfalfa Tysdal, H. M. 1940. Is tripping necessary for seed setting in alfalfa? Amer. Soc . Agron. Jour. 32: 570-585. p. 582: One factor ... is the effect of constant visits of honey bees to the same flower. When the bees are extremely numerous the same flower may be visited a great many times, and in this way a higher percentage of flowers are tripped than shown in Table 10. Actual counts have shown honey bees to trip as much as 12% of the flowers of a given raceme during the course of two or three days. This would indicat9i__th.at_hon3.y baes in abundance might be .beneficial for seed setting. It has also been observed that certain honey bees are much more apt to trip alfalfa flowers than others, thus indicating rather wide differences among individuals in the same species. Plants also differ in ease of tripping. Tysdal, H. M. , and Westover, H. L. 1937. Alfalfa improvement. U. S. Dept . Agr. Yearbook 1937: 1122-1153. p. 1139: The_ ability of the honey bee (Apis mellifera L.) to trip alfalfa flowers is not so easily clarified. Piper et ai. found. .that honey bees tripped only from 0.5 to 4.7 percent of the flowers visited and many visits to the flower were required before tripping ras effected. Dwyer . . ._of Australia, has found that honey bees cause a considerable amount of tripping and has suggested the use of honey bees in cages in breeding work. Michigan workers have also found the honey bee to be effective when confined to small areas^ Helmbold . . . states that Jionay bees collecting pollen cause tripping and attributes more tripping to them than to bumblebees. - 31 - Brassica Magruder, R. 1937. Improvement in the leafy cruciferous vegetables. U. S. Dept. Agr. Yearbook 1937: 283-299. p. 283: According to most botanists, cabbage, cauliflower, broccoli, gr ^an-sprouting broccoli, brussels sprouts, kale, col lards, and kohlrabi are very closely related, being horticultural forms of the species Brassica oleracea L. p. 291: By planting in alternate rows strains that are self- compatible but cross-fertile, hybrid seed will result through the action of insects in carrying the pollen from one strain to the other . Bud pollination of a few flower clusters of each strain results in enough seed to perpetuate the strains for later crops. Bees have been found to be very effective agents in_the cross transfer of pollen , and by enclosing the individuals or groups of plants under cheesecloth cages the bees may be used in working out the problem of obtaining desirable crosses between different strains or increasing the seed of a number of desirable crosses for preliminary commercial tests ... , Broccoli Pearson, 0. H. 1932. Incompatibility in broccoli and the production of seed under cages. Amer. Soc . Hort. Sci. Proc. 29: 468-471. p. 469: The results given here indicate that the use of small numbers of bees under cheesecloth cages is a possible method of pro- ducing small quantities of broccoli seed, if the compatibility situa- tion is such that seed can be produced with the pollen available. Buckwheat Leighty, C. E. 1919. Buckwheat. U. S. Dept. Agr. Farmers' Bui. 1062, 24 pp. pp. 21-22: It is not advisable to grow buckwheat for use by bees alone. Commercial beekeeping in buckwheat-growing sections is advisable, as bees can make use of the flowers produced and may in turn be of use in fertilizing the flowers. Many buckwheat growers, in fact, believe that the weight per bushel of the seed is heavier where the crop has been worked largely by bees . Cabbage Pearson, 0. H. 1932. Breeding plants of the cabbage group. Calif. Agr. Expt. Sta. Bui. 532, 22 pp. -32 - pp. 4-5: Insects visit the flower (Brassica oleracea) freely. Honeybees, although usually plentiful, often fail to be very efficient, because they do not work at temperatures below 60c F. Bumble-bees are not very plentiful in California, but usually a few of them are col- lecting pollen in nearly every field. P • 7 : Cross-pollination which is .the ...rule- in Brassica is usually brought about_by_ insect visitation. Bees are the active poli- nating agents. Clover, Alsike Megee, C, R. , and Kelty, R. H. 1972. The influence of bees upon clover and alfalfa seed production. Mich. Agr. Expt. Sta. Quart. Bui. 14 (4): 271-277. p. 277: The honeybee was found to be a very effective pol- linating agent for June and alsike clovers and for alfalfa and the presence of large numbers of bees resulted in marked Increases in V e seed crops_of_these_legi;umes. United States Department of Agriculture. 1942, A much larger harvest of hay crop seeds needed in 1942. U. S. Dept. Agr., Food for Freedom Program, Background Information Series, No. 7, 5 pp. p. 3: The placement of one hive of honeybees per acre adjacent to or in an alsike field will materially increase seed production. Clover, Crimson Hollowell, E. A. 1933. Crimson clover. U. S. Dept. Agr. Leaflet 160, 8 pp. p. 8: Crimson clover is a prolific seed-producing plant and yields of 5 to 10 bushels per acre are common, depending upon the thickness of the stand, the amount of growth that is produced, and the care exercised in harvesting the seed. The florets are self-fertile, but bees are_..ef festive in tripping and transferring the_pollen^_witIi a. consequent increase in the number of seed per head. The placing of colonies of honeybees_ad i agent to blooming fields will effectively in- crease pollination. Clover, Ladino White Hollowell, E. A. 1942. Ladino white clover for the Northeastern States, U. S. Dept. Agr. Farmers' Bui. 1910, 10 pp. p. 10: Because cross-pollination is necessary for seed forraa- t ion, it is advisable to move hives of honeybees adjacent to the - 33 - fields before _the plants bloom. A minimum of one hive per acre mate- rially increases seed production. Clover, Red Hollowell, E. A. 1932. Red-clover seed production in the Intermountain States. U. S. Dept. Agr. Leaflet 93, 7 pp. p. 7: The dependence of seed setting on the number and activity of honeybees and bumblebees is not realized by most farmers who grow red-clover seed. The red-clover flower is practically self-sterile; that is, the pollen of a flower will not fertilize any other flower on any head of the same plant. Therefore, before fertilization can occur, it is necessary that the pollen be transferred between flowers on different plants. This cross-pollination is done principally by honeybees, bumblebees, and other kinds of bees,, whose presence in large numbers at the time red clover is blooming is essential for large yields of seed. If other nectar and pollen producing plants more liked by the bees than red clover are available, the honeybees in particular will work the other plants in preference to the red-clover flowers. If only the second growth is saved for seed, the time of cutting the first growth may be regulated so that the second growth will be in full bloom v/hen other flowering plants are scarce and then large numbers of bees are present. There is reason to believe that in sections where an increase in acreage_has been accompanied by d^cl liv- ing yields of , soed ,^the_introduction of _additional_colonies of honey- bees would prove profitable. Bumblebee nests should not be destroyed, and every effort should be made to provide desirable nesting places for queen bumblebees. Pieters, A. J., and Hollowell, E. A. 1937. Clover improvement. U. S. Dept. Agr. Yearbook 1937: 1190-1214. p . 1 1 99 : Bees visit the_red_clover_floret_for_nectar_and_pollen or both, tripping the florets and transferring pollen from plant to plant, thus constantly maintaining the condition of mixed inheritance ^~ the species. Other insects, such as moths, are constantly seen on red clover heads, but they do not come in contact with the pollen and therefore do not effect cross-pollination. There has been considerable controversy as to the extent to which pollination can be accomplished by honeybees. Discussion has centered upon the fact that the tongue of the honeybee is not long enough to reach the nectar. The literature on this subject is volumin- ous and cannot be reviewed here. More raceqt investigations cloarl./ indicate that honeybees visit red clover principally for pollen and seldom obtain nectar, but regardless of what is obtained, pollen is transferred and cross-pollination is effected. - 34 - United States Department of Agriculture. 1942. A much larger harvest of hay crop seeds needed in 1942. U. S. Dept. Agr. , Food for Freedom Program, Background Information Series, No. 7, 5 pp. p. 3: A lack of sufficient pollination insects when red clover is blooming is one reason for low seed yields, Honeybees, ._ one of the principal pollinators of redclover, are, the onty__kincl_ that can be reicUly increased_and moved. The placement of one .hive of honeybee per acre adjacent to or in a red clover field when blooming will in- crease seed production. Clover, Strawberry Hollowell, E. A. 1939. Strawberry clover. U. S. Dept. Agr. Leaflet 176, 8 pp. p. 6: The blossoms of strawberry clover are visited by honey- bees. Apparently they obtain considerable nectar, which indicate'; that this is a good honey plant. Clover, White Hollowell, E. A. 1936. White clover. U, S. Dept. Agr. Leaflet 119, 8 pp. p. 7: White clover is naturally a free-blossoming plant in all parts of the United States, but only in a few sections has seed production developed as a farm enterprise. ... Even when blossoms are abundant, moist, cloudy weather is unfavorable to bee activity, necessary cross-pollination is, therefore, restricted and seed produc- tion reduced. The presence of colonies cf honeybees...!?:, .the immediate vicinity of clover-seed produaing fields usually, insures a_maxLimum of cress-pollination. Cotton Allard, H. A. 1910. Preliminary observations concerning natural crossing in cotton. Amer. Breeders' Mag. 1: 247-261. pp. 256-257: Honeybees are among the most frequent visitors of cotton blossoms, but, at the same time, they are very generally visitors of the outer involucral nectaries alone. ... Nearly all bee visitors show a marked tendency to pass from plant to plant up and down the rows rather than across. p. 258: These casual records are sufficient to show the enormous number of blossoms a single bee is capable of visiting in a few hours, and the probabilities of intercrossing a great number of these all over - 35 - the field. Almost before day, bees are forcing their way into the expanding buds, and an examination of these reveals many whose stigmas have been pollinated long before the flowers are fully opened. The writer has observed that in the near vicinity of domestic hives in northern Georgia the number of honeybee visitors is enormously in- creased. p. 261: In cotton fields of northern Georgia the demonstrated proportion of crossed blossoms is at least 20 per cent, with strong probabilities that approximately 40 per cent of the blossoms are crossed. Although crossing may be very detrimental in unselected cotton, in selected cotton it is probably beneficial. Kearney, T. H. 1923. Self-fertilization and cross-fertilization in Pima cotton. U. S. Dept. Agr. Dept. Bui. 1134, 68 pp. p. 36: There is little doubt that natural cross-pollination in cotton is effected almost solely by the agency of insects. The nature of the pollen grains of Gossypium is unfavorable to their transportation by currents of air. p. 37: Various Hymenoptera are the most efficient carriers of cotton pollen at Sacaton, Ariz., as is probably the case v/herever cotton is grown. The honeybee and the wild bees (Melissodes spp.) are the most important cotton pollinators in this locality . The honeybee (Apis mellifica L. ) is very assiduous in its visits to cotton flowers, although sometimes preferring the extra- floral nectaries to those with the flower. Nevertheless, this insect probably holds first rank at Sacaton, Ariz. , as a conveyor of cotton pollen, especially among Pima flowers. As was noted on a preceding page, honeybees entering and emerging from the flowers when the petals are just beginning to unfold almost invariably come in contact with the reproductive organs. Meade, R. M. 1918. Bee keeping may increase the cotton crop. Jour. Kered. 9: 282- 285. p. 285: No effort was made to exclude insects, and the weather conditions during the course of the investigation were not unfavorable to their activities. It is evident from the increased yield of bolls secured in the long-pistiled Durango variety through artificial pol- lination that the presence of additional pollinating insects would aid in reducing the high percentage of shedding. The value of honey bses in this connection is r?oognized_in some localities, .and it would s 9 em that growers of long stapled varieties might find beekeeping a distinct advantage to the cotton crop. - 36 - Cruciferous Root Vegetables Poole, C. F. 1937. Improving the root vegetables. U. S. Dept. Agr. Yearbook 1937: 300-325. p. 310: The cruciferous root vegetables— turnips, rutabagas, and radishes— have relatively large flowers, which are insect-pollinated. Onion Jones, H. A. 1937. Onion improvement. U. S. Dept. Agr. Yearbook 1937: 233-250. p, 239: Most of the pollen is shed between 9 a.m. and 5 p.m. Pollination is effected mainly by insects that go from flower to flower and visit the nectaries at the base of the three inner stamens . Interpollination among flowers of the same umbel is no doubt of fre- quent occurrence, as the same insect has been observed to visit many flowers on an umbel before leaving. In the onion, however, cross- pollination is the rule. Pepper . , Odland, M. L., and Porter, A. N. 1941. A study of natural crossing in peppers (Capsicum frutescens) . Amer. Soc. Hort. Sci. Proc. 38: 585-588, tables. p. 588: The pepper flower is rather inconspicuous and non- fragrant, a fact that would suggest pollination not very likely. Erwin ... found that the flowers produced nectar and that insects did at times visit them. The writers are of the opinion that honey bees are largely responsible for the cross pollination that takes place . This insect has been found working on the pepper plant rather often. The_presen.ce._of the bee is rather spasmodic, however, as they are found only on certain warm b right days. The presence of bees in the vicinity may have a bearing on the amount ofcrcss pollination. Soybean Morse, W. J., and Cartter, J. L. 1937. Improvement in soybeans. U. S. Dept. Agr. Yearbook 1937: 1154- 11E9. p. 1167: Natural crossing in soybeans is undoubtedly brought aDOut by small insects. Thrips have been observed to be very common in the soybean flowers at the Arlington Experiment Farm. Beesand other, _insects have also been observed working on soyogan flowers . Studies by many investigators at various places indicate that soybean plants growing in contact with one another are more likely to be crossed tnan plants separated by a few feet. - 37 - Sweetclover Pieters, A. J., and Hollowell, E. A. 1S37. Clover improvement. U. S. Dept. Agr. Yearbook 1937: 1190-1214. p. 1207: Pollination of sweetclover under natural conditions is effected principally by honeybees, except insofar as the species, varieties, or individuals are spontaneously self-fertilized. United States Department of Agriculture. 1342. A much larger harvest of hay crop seeds needed in 1942. U. S. Dept. Agr. Food for Freedom Program, Background Information Series, No. 7, 5 pp. p. 3: ... lack of sufficient pollination lowers seed yields. Honeybees are the most valuable pollinators. A minimum of one hive of honeybees per acre located close to a blossoming field of sweet clover will increase the quantity of seed set. Trefoil McKee, R., and Schoth, H. A. 1941. Birdsfoot trefoil and big trefoil. U. S. Dept. Agr. Cir. 625, 13 pp. p. 5: The general conclusion of investigators who have studied seed setting in Lotus species is that both birdsfoot trefoil and big trefoil are practically sslf-sterile. Silow ... who has more recently given the subject consideration draws the following conclusion: "Lotus cornicuiatus is practically self-sterile, but occa- sional plants set a few seeds after self-pollination. Plants of L.jaa.i or Smith (^ L^ uliginosus Schk.) are, on the whole, incapable of spontaneous self-pollination, but after artificial self-pollina- tion practically all plants are self- fertile, some to a very high degree . Thus these two perennial species are almost entirely de- pendent upon insect visitors for seed formation. " - 38 - Forage Crops Grown for Seed in_Oregon The following data on forage crops grown for seed which require insects for pollination were furnished by H. A. Schoth through K. S. Senile;-, of the Oregon Agricultural College, who stated: "All leguir.es prob- ably benefit except subterranean clover. Sunflowers probably benefit materially. " Acreage Crops Estimated Goal 1941 1942 Areas of production Alfalfa 1/ 8,000 10,000 Clover, alsike 25,000 30,000 Clover crimson 5,000 20,000 Clover, red 1/ 12,000 14.000 Clover, strawberry 450 Clover, white 1/.... 6,000 (Ladino and other) 500 8 . 000 Lotus 450 500 Rape 1/ 800 1,200 Sweetclover 300 500 Votch. common and Hungarian 18,000 30,000 Vetch, hairy 125,000 185,000 Vetch, purple 3,000 3,000 Vetch, Willamette.. 15,000 35,000 Eastern and southern Oregon. Willamette Valley, southeastern Oregon, Klamath and Deschutes Counties. Willamette Valley. Willamette Valley, southeastern and Central Oregon. Eastern Oregon, Umatilla, Eaker, Malheur, Union, and Klamath Counties. Willamette Valley, central and southeastern Oregon, Umatilla, Jackson, and Josephine Counties. Jackson County, a little in Clatsop County. Willamette Valley, Malheur County. Willamette Valley, eastern Oregon. Willamette Valley, southern Oregon. Willamette and Umpqua Valleys, central Oregon, Jackson and Josephine Counties. Willamette and Umpqua Valleys, Coos County. Willamette Valley. 1/ Cross-pollination undesirable, especially from the standpoint of producing certified seed. - 39 - Truck-Crop Plants Grown for Seed in California The following table, showing some truck-crop plants requiring in- sect pollination for seed production, was furnished by G. C. Hanna, of the University of California: Plant Time of blossoming Locality Asparagus July-August Sacramento Delta Carrots June-July Salinas Valley, Cotati Cauliflower April-June Santa Maria, Half moon Bay Cantaloup ) Cucumber ) Pumpkin ) July-August Sacramento and San Joaquin Squash ) Valleys Watermelon ) UNIVERSITY OF FLORIDA I911II1I1III1IIIIIIII111 3 1262 09224 7179 \ i