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The Green Apple Bug in Nova Scotia. — BY — W. H. BRITTAIN, Provincial Entomoloyi>:7. To the lloii. Ut'orgf II. Murray, Provincial Secretary, Halifax, N. S. Sir: — r have the lioiior to traii8iiiit HuHetln No. S, eiitit!"ub)ication and distribution. I liave tile honor to he. Sir, Vour obedient servant, M. (TMM'.XCJ, Secntniij fill- AfirirultiirA. THE GREEN APPLE B UG (LroUB COMMUNIS VAR. NO V A SC OT I B N •! « K NIOHT I The Green Apple Bug in Nova Scotia. — BY — W. H. BRIFTAIN. EXPLANATION OF COLORED PLATE.— A'"/""- /, '. /. 4 (tuil 't niirfKi'iil tii'<' siirr>'it/iir' ■ihii/i'K nf tin' iii/iiil>h tn' iitlltnitiii'i' lii-iiii ; fiifWf (t, thf iiihili • liijiiii /'. tliiCf 11/ l/ir ii/iiK , fii/iiii .V, n (•nil ilni'lir hiiirin(f '/"mi;; (iitit^-i* inimliiinl tn/ the iiimrt dinl nliniiiiiii nijint/ to yoiintf leitrin. INTRODUCTION. Tlu' invcstiKHtioii of eh this Ixillctiii is the nsult, li is only cxtciKlcti ovt-r two hc us. Ncvfriliclt'ss tlu- chief points ill tlu' life history of the ii.scct liavc hrt'ii \vorUf» these nuitters, i .eenn-d best to otfer this inforniatiiui to the puhli" at the present time. The result of furlher worU wiM he issued in circular form as it is completed. GENERAL SUMMARY. 1. The (Sreen Apple \^\\^ has been jiresent in Xova Scotia for many years, but has only recently been recojrni/ed as beiiii? respon.sible for the danmpe of which it is the cause. 2. Its injury is widespread in the counties of Hants, Kings, Aniuipolis and Digby, and it is possibly present in other •counties, as well .a in the province of Prince Edward Island. 6 •i. It is, where picst'iit, tile most scrioiis enemy of t!u. fruit-grower, and while not so general as some other pests, the damage that it does is most sweeping and the insect most dif- tieult to eradicate. 4. The insect has oidy been found to breed on the apple, j)ear and quince, though in the immature, or nymphal stag'.'S, it feeds on various other plants and in the adidt state frequent- ly attacks plums. 5. The insect, when newly hatched, resembles a small yel- low aphis in appearance though much more active. As it in- creases in size it becomes bright green aiul finally reaches the length of one-sixth of an inch. It then moults and assumes the adult or winged form. It is then a fragile insect with relative- ly long legs and antennae, and in color a combination of liiiht and dark brown. In this stage it closely resembles the common tarnished plant bug (Lygus pratensis Linn.) 6. The young begin to emerge several days before the blossoms open, the maximum emergence coinciding with the period of full bloom of the Bartlett pear, or .jii t as the Grav- enstein blossoms begin to open. The nymphal stage is of about 32 days duration. The adults begin to die off within a couple- of weeks after reaching maturity, but are found in diminish- ing luimbers throughout the summer and early axitumn. The winter is passed in the egg state, beneath the bark of the twigs. 7. The young bugs or nymphs are very active and elusive in their habits and as they increase in size, exhibit an increas- ed tendency to drop to the ground. Leaves, stems, blossoms and fruit are freely attacked, but blossoms and fruit are pre- ferred. They are occasionally predaceous in habit, and though apparently fragile, can exist for several days without food and are able to make their way over the ground for compara- tively long distances. H. The adults are active insects and strong fliers, though, under ordinary conditions, they do not appear to wander far from the orchard in which they have developed. In feeding, the adults prefer a diet of fruit, and that of pears is most at- tractive to them when they first reach maturity. 9. The first injury to the apples appears as small purple- spots upon the leaves, which, as the leaf grows, develop into small perforations. The new succulent shoots are also injured,. and in s»'ven' cases wilt and die. Tli«' blossoms arc fn-cly at- tacked as soon as they api)ear, and as a resnlt they also shrivel up and die. Injnry to the young fruit is tirst shown by befnis of sap oozing through the skin, later by a reddish pimple, marking the spot. A large proportion of the injured ai)pl'>s drop to the ground, otherwise they are badly searn'd and twisted. Continued severe attacks result in a gradual weaken- ing of the vigor of the tree. Injury to the quince reseml'les that of the apple, but is not so severe. 10. Though the insect breeds on the pear to a certain ;'X- tent the greatest injury to the fruit of this tree apjjears to be caused by adults that fly to the pears from infested apples. Their injury cause unsightly brown, corky scars upon the fruit, and hard, flinty kernels extending into the pulp. Siicli fruit has been popularly known as "woody pears." 11. Plums are also injured by adults flying in from oit- side, causing an exudation of colorless gum from the infesivnl fruit. 12. Nymphs that fall from the trees are capable of com- pleting their tlevelopment on various weeds and grasses grow- ing in the orchard. 13. The insect aids in the spread of and increases tne losses from European Canker (Nectria ditissinia) and is ■\ car- rier of Fire Blight (Bacillus amylovorus). 14. Observation and experience has shown that, while of all varieties of apples, the Nonpareil (Roxbury Russet) suffers most severely, others approach it in susceptibility, while none appear to be immiuie. Among pears Bartletts usually suffer .most. 15. Conditions favoring increase are heavy shade, poor air circulation and lack of clean cultivation in the spring and early summer. Destructive outbreaks may occur, however, under a wide range of conditions. 16. Natural enemies have not yet been found to play an important part in the control of the pest, though ants and spid- •ers destroy a certain number. 17. The control of the insect is made difficult by its elu- sive habits, by its ability to hide in inaccessible places, bv the .density of the foliage at the time the spraying must be done, 8 and by the fact that many of the l)ugs fall off the trees, only to make their way back again after the spraying is finished. The following methods have been found effective: (r) The trees must be properly pruned and must not l)e- too close together, so that all parts are readily accessible to the spray. (b) The trees should be banded with tree tanglefoot pre- vious to spraying wherever the insects are numerous, to pre- vent the reascent of those insects that have fallen to the ground. If the insects could be sprayed within a few days of emerg- ence this would not always be necessary, but owing to the period over which they are emerging, to possible delays duo to wet weather, and to the length of time required to spray an orchard of any size, sonu^ insects might be well grown before it was possible to spray the whole orchard. Again, if the o?*ch- ard could be harrowed immediately after spraying banding; might be dispensed with, but this is not often possible. (c) Apple trees shoidd be sprayed with nicotine sulphhte (Blackleaf 40) just before the blossoms open, and, if nrees- sary, again just after they fall, u.sing a strength of from % of a pint to 1 pint for each 100 gals, of spray. The weaker strengths: may be safely used, especially for the earlier spraying, provid- ed the material is properly applied. Since pears are most sen- ously infested by adults flying from nearby apple trees, the remedy for pears is, first of all, to spray the infested apples. For pear trees infested by the nymphs, one spray just after the blossoms have fallen is usually sufficient. (d) A very heavy, drenching, driving si)ray is necessary, that will reach all parts where the bug is likely to hide. Best results were obtained by the use of a drive nozzle and a press- ure of not less than 175 lbs. Spray each limb individually from every angle, taking particular care that the centre and top of the tree is given just as thorough treatment as the outside. Do not be afraid of "wasting spray" or failure is certain to result. (e) All these precautions if properly carried out, cannot fail to control the pest, but neglect of any one of them may re- sult in complete failure. 9 HISTORY. For many years past, so-called "woody pears" have been known and eoiiimented npon by fruit growers throughout ^!ie Annapolis Valley, such pears being .-overed with corky dis- figuring scars, so as to be rendered quite wortiiless. Tliis trouble, which lias annually destroyed a very large propor- tion of tile pear crop, was coimnonly ascribed to lack of iron in the soil, and not uncoiiinionly liberal ai)plications of iron fil- ings were made to remedy this condition, but naturally wifhcut result. Within the past ten years an increasing number of or-h- ards that formerly bore heavy crops, have been gradually go- ing back, until they finally yield only gnarled and twisted aj)- ples, or in some cases, none whatever. Further investigation has shown that a number of orchards have grown up and come to bearing age without ever yielding a crop of fruit, or only fruit of tile inferior kind already described. This state of af- fairs was all the more puzzling to the fruit-growers, since such trees almost invariably came into blossom each year. The most common comi)laints have been regarding the non-be;iriiig of the Nonpareil (Roxbury Kiisset), but examination showed that the trouble was not by any means confined to this variety, though it undoubtedly suffered as severely, or more sevrely, than any other. No one api)ears to have suspected that the trouble in the apjiles had any connection with that of the pears, or that either was of insect origin. In June, 1914, the writer visited an orchard near Wolfville, N. S., consisting of mature trei-s of various standard varieties, including Nonpareils, Kibstoii, Gravenstein, Golden Kusset, as well as several varieties of pears. The owner stat.'d that the orcliari. had been gradii.iHy going back for the i)ast ten years, that for at K'ast six y»;srs the Nonpareils had borne no crop, and that the trouble !iad gradually spread to the other varietie;-,, until they too had ecis- ed to bear. Some years before a imiiiber of pear liees had been cut down, because the fiuit persisted in "groviiiig woody", ami those that remained were all going the same way every year. All the ordinary sprays had been tried, vavi us fertilizers were applied, and the orchard under-drained i:i a'l effort to arrest the trouble, which, however, steadily grew worse. In fact, though this orchard was one of the best cared- for in th(> Valley and was formerly a splendid producer, it h-.id at length reached the point where no croj) at all was being p.-o- ■duced. An examination of the trees showed them to be swarm- 10 uxg with prct'ii nymphs of the insect now popularly known tlirouj^hoiit the Annapolis Valley as the "Green Apple Bus?", anil a earetul study of the feeding; liabits of the insect pro"e(l conclusively that it was the real culprit. For the past two seasons observations have been taken in many similar orchards throughout the province, and further investigations have only tended to confirm our earlier conclusions. DISTRIBUTION AND SPREAD. The pest seems to be well distributed throughout the fruit- growing centres of Nova Scotia and also where apples arc rot grown to any extent commercially. .More or less severe in- festations have been located throughout the counties of Hants, Kings, Annapolis and Digby, and i..pical "'voody pears" have also been sent in from Prince Edward Islaiul. It wouhl at fi''st seem that the jjcst was more widely distributed on pears tlian oil apples, the phrase "injury to jiears only" occurring v uli considerably frequency in the rei)orts of the entomological in- spectors. This, however, is i)rol)ably due to the fact th-it whereas most of the injured pears remain clinging to the tree, the apples are largely destroyed while still in the blossom stage and later a large proportion of the injured apples drop to the ground. Though experiments have shown that the adults are capable oi flying considerablt> distances, the jiest appears to spread *)at slowly from orchard to orchard. Orchards in close proximity to one another vary greatly in their degree of infestation. Con- tinued observations have shown that a light but uniform in- festation may suddenly ilevelop into a very severe one, from one season to the next. (Jrowers should therefore keep careful watch to discover any incipient outbreak before it has tin:,; to develop to such an extent as to menace the cro{). SERIOUSNESS OF PEST. Sufficient has alreaely been written to indicate that this insect is a very serious pest of the apple and pear, but any esti- mate of the actual tlaniage would, of course, be out of the ques- tion. Though as yet many orchards are still free or compira- tively free from attack, it is nevertheless a fact that where the green apjile bug has become established, there is no pest to compare with it, either in the amount of damage done or in the difficulty that is experienced in controlling it. The pears in many orchards have for years been so scarred as to be quite 11 uiiniark('tal)l«' and in nnnuTons apijlc orclianis the crop lias been greatly rt'dnt'cd. or even dcstroyt'd. Further than this, the vitality of many trees lias been seriously impaired and I'l'iiit spurs either killed or rendered useless from the attaeks ol' Mie inseet. Many growers who, two years apo never knew of the existeiK'e of the pest, will now state eontideiitly that it is tin- worst inseet with whieli they have to eontend. The apple crop in the Annaiiolis Valley has not been in- creasing at the rate one would expect from the new aen aije •constantly reaching bearing age each year. On the eontraiy it seems to have, on the whole, actually gone back. There is lit- tle doubt in the mind of the writer that this condition of iillairs can be to a large extent laid at the door of the green apjile bug. In any case there can be no doubt that numbers of growt'rs will have to aliandon apple growing, if they do ih t bring this pest under control. HOST PLANTS. As far as we have determined, the insect oidy breciU mi the apple, ])ear, quince, tind possibly the rose. Young nym|)hs were found in consiiierable numbers feeding on rose Inishes planted in sod, and about twenty feet from the nearest apjile tree, but it is quite possible that the insects fell from the tr 'cs and made their way over the ground to the rose bushes. Xymphs were also found on a young elm tree beneath infested apples, but though elm trees are abundant near infested orchards, iliis is the only case in which we have found them infested by the insect. When shaken from the tree, the nymphs have been ob- served to feed upon a large number of weeds and gr;!SK -s growing beneath the tree, but on reaching the adult stage liny invariably seek the apple, pear or quince to feed and deposit their eggs. THE INSECT. The young insects, or nymphs, are pale ; sjlitly yi-llow- ish insects about 1-25 of an inch long when f.i hatched. In the third nyinphal stage they become a bright green and wlen full grown are slightly yellowish about the head and thorax, measuring about 1-6 of an inch long. The adult is a delicute insect 14 of «" inch long. When newly I'lnerged it is quite p-de in color, but later becomes a combination of light and dark browns, though individual insects vary greatly as regards 12 color. In appearance it bears a close resemblance t blosBom buds when the first bug was found emerging In the orchard. 13 The nymphs seem to emerge simultaneously on both early anA late varieties, but keep emerging for a longer period from late varieties such as the Nonpareil. The duration of the firtt nymphal instar is 5.22 days (average of 52 individuals); of second, 5.43 days (average of 34 individuals) ; of the third, 6.66 days (average of 34 individuals) ; of the fourth, 6.77 dayi (average of 24 individuals), and of the fifth, 6.83 days (aver- age of 12 individuals). In 1915 the first adults were taken on June 27th, mo.st of the nymphs becoming mature by July 5th. In all the time that this insect has been under observatioij, no nymphs have been observed later than the first week in July, all liaving completed their transformation by that date. The length of the adult stage varies greatly, single individuals havitig been taken in the orchard as late us the last of September. During the sea- son of 1915 adults were first taken on June 23rd, the greater number reaching the adult stage by July 3rd. The accompanying table gives the details of the life hist- ory of 12 individuals which were reareii from the egg stage t* the adult stage during the season of 191.'): 14 O z tu _l m < I- ON O D n O O o H en « 'in JO njrtuai |«v>x 5 t^Msessrrsxt-. — — t- I — •» I- It 1 1- tf L« as I us :' r- a!, r- t- t^ t"- 1- !■• I- :£ t: r» .-^r~ hf I'JK i>ur. t-It~t-.Xl-I'rt-;CIt-. t* t- t- t~ C 1- I t- 1- t- :0 a; IT i ■■c 1- f 1- « t^ t- » » ifl t» X t- id IS I II? »■? t :c •*• I:? *?" i* »(? ^ :c to iHV-n' JO aiBQ •Jliioiu i|i(; JO a%va •Jinoui mi- JO ajBQ •j[iioiu pjg JO ajflQ ■^ n » s IT t- Ti Ti •^ 11? -r 1" ►T St ^1 ?i Ti Ti Tt rt Ti Ti "71 -M ?i Ti >u §=—— — — — 7*1 1-< T1 r» ^1 -?! -^ ri »-^ ^ -M ri s «^tr*:C — iTO?C'M:c»cx •Jiniilll ptif. JO B'JBd »t-XOXX'>1r this time to find a inimber of'de-id biifjs fastened alont; the nudrib of sinjrie apple leaf. Th« bugs have a habit, when altout to ilie. of extrudinir tl caudal extremity of the alimentary canal, which is covered by a viscid secretion, by means of which they attach themselves to the leaf. This same habit was observed in the case of bujrs killed by our sprays. A birp' pro|)orti()n stuck themselves to iht leaves in this way. and did not drop off on the sheets spreac! beneath the tree until soii.e hours later. Though jarge numbers of bii<;s died during the latter part of .July. 1915, there was no ditt'ieulty in finding specimens through the month of August and early September. Aftt that, individual six pecimeiis could only be located with ditt'iculfv. On Aujrust 27th ')() adidts were collected, 4 iiioiitti of July, but it cwi- tiiiuvH throuKli Au^uHt and t'wn lat«*r. Tlx' t'ggn are laiil in fruit HpurN, HUc-ks, between the blossom pedicels, or in a'ly place that afTords eoncealnu-nt. The yoiui^ nymphs do not readily drop to the ground, and are not washed otT to any jjreat extent even by heavy rains, but, as they increase in size, they exhibit an inereasiiiK tendency to drop when disturbed. When trees infested with the bugs are sprayed at a time Avhen Hie insects are over half provn, the backs of the horses are some- times Ki"*e» with the nymphs that drop from the trees. Our observations show that first and second sta>?e nymphs will run rapidly in an attempt to conceal themselves when disturbed, but will rarely drop to the ground unless forced to do so. Tiiiid static nymphs show a tendency to drop, while fourth and fifth Btape nymphs dro|) still more readily. The newly hatched nymphs seem to prefer the folia ■, it has been observed that the insects are ap- parently les. iiierous about the trees. A careful examiiui- tion shows th^i large niuubers of them have made their way into the blossoms, where they hav hidden themselves among 17 tin- HtHiiU'iiH. jH many iim ciKlit ii.viiiphf. Iiavi- bccii foiiiKl iiisidp H HiiiKlf hloHNoiii. Kfoiii tliiM tiiiif on thfir iittcntion In altnast •■ritirt'ly confined to ll!«)^;sonl^^ and fruit, tin- IravcM and twi^M, \vi»h tin- ('Xccption of the new growth. In-in^r altoKftlicr for- HHkt-n. Where the set of fruit on a tree is li^ht, a very few huKH will Hoon destroy it all. and then, no further foo.l'in-ing avaihd)le, fee«l upon leaves and tender twijTM. In feeding, the nymphs roam larjrely ovi-r the tree, .'speeiaily when not nuui-.-r- ous. Heneath a non-infested pear tr«'e twelve fourth sta«?e nymphs were iiherated. and on examininjf the tree next day, their work eoiild readily he detected over almost tl ntire ♦•ee! Like many other Capsids, these insects ronu'tinu-s exhiliit predaceous habits. On one occasion a number of nvmjdis were observed repeatedly thrustinj? their heal. ■ into the larva >,[' a Kreen fruit worm (Xylina sp.) that .. . been eauKht in a tanglefoot band, and cf-ntinued to do so until the caterpillar had be-n sucked completely dry. Several have reported llmt they have been stunt? lO' the insect when passing beneath in- fested trc.'s. If left undisturbed it will sometinu's pi.rcc the skin several times, and remain feeding uniil completely gorged with blood. For such apparently fragile insects the nvmphs an; re- n»arkal)!y strong and active, aniiiioii, wliioh Ih Miip|M»it<'n. 20 All adult was oncf observed with beak inserted in a full-grown tussoek moth (Notoloplius antiqua Linn.) larva, aiul only with dift'ieulty eould it be induced to relinquish its hold. CHARACTER AND EXTENT OF INJURY. 1. Injury to the apple. The first evidence of the insect's injury is found ui)on the young and tender foliage in the form of purplish spots upon the surface. Tliis symptom is very characteristic and makes it possible to detect the presence of the insect almost as soon as it ai)pears, and long before it would be noticed by the ord- inary observer. Twenty-four hours after the insects hatch these spots are already (piite marked. When the insect is pres- ent in large niniibers the leaves exhibit a tendency to curl at the edges as a result of their work. As they unfold and in- crease in size the purplish discoloration gradiially disappears, but if affected leaves are held to the light they will be seen to be pierced through and through with small holes, and in severe cases the leaf may present a very ragged and frayed appear- ance, liy these symptoms the foruu-r pre;-ence of the bvig upoji the leaves uuiy i)e detected, 'ong after it has completed its tiansformations and disappeared. The tender, .suvculent twigs of the eiu'rent season's growth and even harder wood, is freely attacked, ti.e point of puncture being often marked by a drop of clear or yellowish saj) oozing through the bark. As the twig increa.se;; in size a decided lump develops at this point, and in rapidly growing shoot'; a longitudinal crack will sonu'tinu's appear. In heavily infested orchard:;, where the insect will be present in countless thou- stct (lid not feed readily upon this plant. Sweet Cherry (Prunus avium). — A slight i)uncturin.'': of the leaves and blosKoms and gummy exudations from the fniit, but injury not pronounced. 24 Feaoh (Prunus pcrsica).— Li'uv.'s Khow.-d i>laiii!.y the <-ii • ct of thi' iur,ec'ts" i)uiieturiM, and small globuU-s ot traiwpa.' "t gum issued from iinuivd fiuit. Strawberry (Fragaria Virginia ua).—StrawlM'rrii's showed' evith'UCH' of eonsidcrahk' injury; blossoms and l»;ayt's \v.'r<> so- badly punctured that tlii-y finally withered and du'd. Couch Grass (Agropyrum repensV— The injury to +he blades of couch grass was marked, the plants beconnng notice- ably wilted and faiU'd in color. Dock (Rumex crispus).— Fed readily on the plant, pu):ct- uring leaves and fruit. In the si)ring of 1916, 25 plants, conniion in and about orchards, were planted in inus in the greenhouse, and on each were placed five second and third stage nymnlis, with tli.; fol- lowing results : Plant. So. Reaching Maturity. ChlckweeJ (Stellaria mcaia) 2 Rose (Rosa rugosa) ^ Sw fit Briar (Rosa rublginosa) 2 Cultivate-J Strawberry (Fragaria virginiana) 4 Wild Strawberry (Fragaria chiloensis) 2' Buttercup (Ranunculus acria) <> Danlellon (Taraxacum officinale) 1 Goken Rod (Solidago gramimfolia) 0' Golden Rod (Sollcago graminifolia) <>• Broadleaf Plantain (Plantago major) 3 Narrcvleat Planta:n (Plantago lanceolata) 2: Coucli Grass (Agropyrum repens) 3 Daisy (Chrysanthemum leucanthemum) 1 Mullein (Verbascum thapsus) ^ Yarrow (Achillea millefolium) 0' Raspberry (Rubus strigosus) 3 Violet (Viola cucullata) ^ Orchard Grass (Dactylis glomerata) 3 Sheep Sorrel (Rumax acetosella) 2 Alslke Clover (Trlfolium hybridum) 4 Rei-top (Agrostis alba) - Dock (Rumex crispus) 2 Fall Dandelion (Leontodon autumnalis) 0 T ral. 40. We 8iH' from tli»' •of oiu' hiiiidrt'd and .327t' n'aclu'd iiiatiirity. 25 foregoing tliat out of a t-.itnl twenty-five, forty nymphs, or This is no index, however, of the number that might come througli under natural eon- • ditious, since the rearing of the insect, even on its natural fcotl plants, is a nmtter of considerable difficulty, and accompanied by a high mortality. Furthermore the weather at the time was • extreiiu'ly damp, and moisture collected freely on the sides of lamp chimneys that were used to cover the plants. THE OEEEN APPLE BUG AND EUROPEAN CANKER (Nectria ditissima). The Euroi)ean canker is very common in the orchards of Nova Scotia, working largely in the larger limbs, frequently causing their death. It appears that the damage from this •disease is largely increased by the presence of large ninubers of the green apple bug. In such cases it '-"« been found lliat an undue amount of this disease is present ii aller liii'bs and twigs. The puncturing of the wood by the \n • of the in- sect affords lodgement for the spores of the fungus, so that the life of many trees is actually menaced by the cond)ination of these two pests. New cankers are commonly seen develop- ing about the spot where the skin has been pierced by the in- :sect. Thougb the evidence that connects this insect with the disease is only circumstantial, it is sufficiently strong to indi- cate that the' presence of this bug is an important factor in ; aggravating the damage done by this disease and in promoting its spread in the orchard. That many insects are active carriers of various plant diseases has been demonstrated experimentally by various work- ers within recent years. Gloyer * and Fulton have rec( nt'y shown that tree crickets (Oecanthus spp.) act as carriers of the fungus, Lei)tosphaeria coniothyreum, from raspberry canes to apple trees. In the sanu> publication these writers also give a .short r.>view of the 'iterature on the transmission of plant • diseases by insects. ■• Gloyer, W. O. & Fulton, B. B., Tree Crickets as Carriers of L,eptosph:ieria coniothyreum Sacc. and other Fungi. Tech. Bull. No. 50, N. Y. Agr. I^xp bia. (1916). 26 Tilt' relation bt'twcen the Lyt?us and Nectria is probrtbly more indirect than the case just referred to. It is i)08sible that gome of the spores of tlie fungus tnay actually elinp to the body of the insect, but its chief role consists in furnishing an opening for the entrance of the summer spores, which are produced abundantly throughout the season, particularly in damp weather. THE GREEN APPLE BUG AND FIRE BLIGHT (Bacillus amylovonis). The withering of blossoms and leaves accompanying the attacks of this pest were so strongly characteristic of fire blight that at first these symptoms were ascribed largely to this disease, and the bugs regarded as carriers. This is only what might be expected, since this correlation between the prevalence of fire blight and the presence of sucking insects has often been observed. Typical specitnens of injured blossom clusters and twigs were accordingly submitted to leading au thorities in the United States and Canada and the trouble diagnosed as fire blight. It soon began to appear, however, that the bug alone was responsible for much of the damage that has been attributed to the disease. In all our work throughout the Valley we never saw any signs of the blight except where the insect was present in large numbers, and its severity varied directly with the degree of insect infestation. Every blighted twig or shoot showed unmistakable signs of having been punctured by the insect. Only very rarely was the disease found to be running back into the previous year's growth, and in spite of a careful search, few so-called "hold- over" cankers could be found. It was found that new shoots generally arise from beneath the injured spur or twig, and the injured growth commonly, but not invariably, falls off before the end of the sea.son. Furthermore, orchards that have sulTer- ed from the blight for years, show no signs of it when the in- sects are destroyed by s^praying. We could always produce a blighted appearance on apple tv,'igs by allowing a number of bugs to feed on them and, as similar symptoms have been ob- served to follow the attacks of aphids reared from the egg state in the laboratory, it WOiild seem difficult, in many cases, to distinguish between the damage done by the disease and that due directly to insect punctures. Specimens were accordingly submitted to Prof. V. B. 27 Sti'wart, Dcpt. of Plant THtholonv, Conicll riiivcrsity. who has recently made a special study of the prohleiii of lire blight traiisiiiissioii l)y siickinf? insects. Prof Stewart express- ed the opinion that while a nnnd)er of the twitfs were iiniiiis- ta'-ahly atVeeted with fire Ijii^lit. a larjre amount of tile In- jury was caused by the insect alone. It would tlius ai)i)ear that, while it is often impossible by a sup<'rticial examination, to distinjruish between the injury done by the bii^t and that oc- casioned by the disease, particularly in old trees where the blight - ties are attacked. Among pears, those of the Bartlett vanety seem to suffer most severely. In fact, it has been believed in some sections that this trouble is a disease of the Bartlett pear, but observa- 28 tioii lias shown fliat variouH others art' t'r.'mn'iitly sfvoroly in- jured. Clapp's Favorite. HurhridKe, Maria, and Flemish lieauty may be ineliuh'tl amonn the H>isee|)til)ie varieties. Other kinds, wliieh do not seem to be as badly attacked, i-re Louis lionne. Hose, Lawrenee, Duehess and D'Aiijou. CONDITIONS FAVORING INCREASE. It is difficult to state definitely inider what conditions the- insect Hourishes best, since it is found in orchards that have been treated in every conceivable way. Sprayed and unspray- ed. clean cultivated and sod, well cared for and neglectod orchards are all attacked. It is a notable fact that numy of the worst infestations are in orchards that have received tin? very best treatment in the way of spraying, fertilization and tilth. In most eases, however, such orchards were unduly shaded, bein^r insufficiently pruned, too thickly planted, or both. Some of the orchards which have suff'ered worst have been cultivated on the strip system, i. e.. with a strip of clover or ^rrass alter- nating? with a clean cultivated strip. In fact, a very large pro- portion of the worst infestations were foniul where there was a certain amoinit of growth at the base of the tree either in the way of sod or weids. This may be due to the fact that in such orchards the large mnnbers of nymphs that invaria))ly drop to the gro\ind are liable to maintain themselves u[)on these |)laiits and so reach nuiturity. whereas, vnider a rigid system of clean eultivatioii. numy would be U!ud)le to reach the tree, while others would be destroyed by cultivation. It was also noticed that in low-lving ground, or where the orchard was screeneil trom the wind, there the infestation was likely to be most severe. As a result of extensive observations throughout th-j in- fested area, it appears that the most suitable conditions for the undue increase of this pest are shady oi'chards with closely planted, thickly growing trees, with poor air drainage, and a certain amount of herbage growing ui)on the ground. Healthy, vigorous ti'ces, nmking an excellent growth, frequently suffer most. and. until weakened by repeated attacks, will put forth a heavy seeondary growth to replace that destroyed by the bug. These foregoing factors are not. however, essential to a destructive outbreak, as the insect is capable of doing injury under a witle range of conditions. All the foregoing refers to apple oi'chards alone, though the sanu' holds good, to a certairh 29 PLATE II. f*^yy ."I*-*/ T»% . ' y "■ <-. \ik^. r^^-'-c. i^j \ A V.4 iiMff jstestefei* "V-J-i-B'i-" ".■ ]^W:i»— -:-l ifftrz^,^ An orchard In which the bug hai destroyed the crop for a number of year* past. (Original.) 30 <.xt.-iit. of |M-Hi- oicluinlH. Til.' proximity of hH.ll.v iiif.-stfd up pie tn-.'H is tlif moHt important factor in brin^inK about in,:ury to tllf prai-H. NATURAL ENEMIES. I'p to tllf pn-K.-nt tinii' w.- Iiavf not fouml any parasit- that fXtTcist-H any appn-ciahlt- cln'ck npon the incn-am- of tin- pest. AntH (Formica fnsca Linn.) Iiavc frcipicntly been ob- served carrvinjt away tiie nymphs in their jaws from tlie trnnits of tlie trees, and doid)tiesH a larRc innnber are destrev- ««d in this nninner. On one occasion, when a number of nympl>s wre liberate 1 at the base of a tree, four of them were seized by U8 many anti' and carried otT throiiKh the ^rass to the ant hill, which" was distant some fifteen feet. Spiders are also aetiv*' in the destroying of the nymphs, but the percentage of mortal- ity from both these sources si'eins to be comi).'.ratively small. 0LAS8IFICATI0N. This liifftt litloiiKM to the MIri.Iiie (I'lipKlila*") whith constitute :>t) Im- portant family beloiiKltiK to the Hiil>-orcler Hetero|itira, order flemll.t'-ni. This family Is liirKely rei>re> tiilns many forniH in- jurious to |>lant». anil others that are predaceous ii'. 1 il>lt. The species herein dlsc-usseil has been Reneral'.y confused with related forms. Karller workers doubtless mistook It for tii» common l.yKUs i r,i- tenals, while of recent years it has Kcnerally been referred to as l.yK"« JnvltUH Say. Recently It has been described as l.yKUs comn\uni8 n. Bp by Ki'.lKht (H). and the Nova Hcotlan form as a new variety under the name novascotlensis (15). AccordinKly, the full name of the in.secl is I.yguH communis var. novas.otienais KnlBht, l-...(>tt and Hod^kiss h-.ive proposed the name of False Tarnished Plant Kutr for- the typic.il communis, t)ut the Nova Scotian variety is now well known in the j.rovince as the green apple bUK. or simply as the "i?reen bug." DESCRIPTION OF LIFE STAGES. EGG.— The cBS Is .smooth and cylindrical, but curvInK sllKhtly tovvi-.rds one side; constricted near broadened and flattened apex Into broad nek, at>out which Is a narrow collar, somewhat wider than the neck; base rounded marBins at centre sliRhtly swollen. Chorion, delicate, coarsely punctured, tranaluctent. Collar, whitish opaque. Cap. coarsely punctured. Ceneral color, pale yellowish white, translucent. Length, .752 mm.— .X35 m.n. "Width. .1!>5 m.n.— .221 mm. Nymph.— The nvmphs resemble each other closely in general form, the ilrst two nvmpha! histars being: pair yellow In color and the last three Kreen, with more or less yellow about the head and thorax. In the last two nym- phal liwtars the wing pads are plainly visible. 31 FIBST IN9TAR, — Hody loiiK, iiurrow: latvrnl marRliiN tiiirr(iw<>.4t at I'ltuilHl niHrKlri of itrothoriix, theiift> wlilenliiK vrry HllKhtly to cauiliil miirfrin of metathurHX, nnil aKalii to liroailent partH at third alxlomlnal ■««ment. H4ad, more or lea* trIaiiKular, liroailly rouixU'il at apex. Pretherax, one-Hlxth loiiKer tliaii icail and of ciiual width, vxcludltiK «y«M; Matetherax, of Hnma IriiKth aM the head, HllKhtly lirfHidrr than prothorax. Abdomtn, pyrlforin, Knllrv doPHul . ace oovert-d with Btout dark halm regularly plao«d, and flti«T halTH IrrcK^larly plarrd, theiie halm, like thoeff- ment, thence tapering gradually to caudal e.xtremlty. Head, similar to pre- ceding instar. Prothorax, equal In length and slightly broader than head, widening towards caudal border; caudal margin slightly procurved. Mf^ao- thb.'ax, one-half length of the prothorax. one-Pfth broamliir(>ri<'iv l^tiKth, 1.37 mr.i.; Iitt it«-Kni«-iil, H" mm.; iiiil Nrirmdit, .1.1s mm.; 3rui on Iril itliilomltiHl H<-Kiiu-iit. AntiMiiiue hmiI leKM |iiilf dull vvllow. Kvj-m iIuII red. Longth of Body, I 5«-2.:>9mm.; wlilth. .711' mm. — .',»l.1 mm. FOURTH INtTAR. — Hody, Ioiik, hroad, oval. llaltciUMl; lateral inaritln» niirrowrxt liehliid t-yfM, Kradually wlderdiiK to thlnl atidominiil Ki-Kmcnt. Hoad, trlaiiKUlar, rnumled. Prethorax, broad. Iiut narrower than iu'-ul: •qual to hi'ail in hiiKth; lateral marKin nllKhtly dhj-rgent; lateral anKli'ri of meMOthorax ami iiif talhorax |>ruJt'<'tlnK raudally, formhiK Hinall wlnn padx. renrhliiK almoxt or quite to third .ihdomlnal Ht-Km nt. Abdomon, tiroad. flutti-ned, pyrlform. l>orHal HUrfat-e Hmooth. Antenna*, Iouk and Miender. LenKth i.73 mm.; iHt H«-Km«nt, ''' ,nm. ; iiui «<•>' lent, .mi nun.; 3rd iieKment, .70x mm.; 4th HeKment, .'sa Legs, lotiK and xlender; hind tlhia I.4K — 1.6 mm. Ioiik. Color, Rreen throuKhout. VellowlHh In head and aboi t wIuk liaiN. I.eRM and antennae pale dull yellowilih. r«ual median alxloMiinal Hpot yellovvlJ'h. Length of Body, :!.75 mm.— 2.!»7 mm.; width, 1.107 mm.— l.lfi mm. FIFTH IN8TAR.— Hody, lonif. elliptical, liroad and tlattened; lat'ral miirKliiH narroweHt liehlnd eyex. curvliiK Kently to caudal marKin, the wideHt part behiK Ju«t half the lenRth of the body. Head, aw in prevlouH »t >«ee. but relatively Hinaller. Prothorax, equal in lenKth to hcail; anterior maru- InM dlverKeiit caudally. Meaothorax, one-Hlxth ttho tcr than prothor.ix. Matathorax, one-fourth lenKth of ni «"• ., nx. WIr ^ nadn lonK, round.-d, extendhiK almost to t'audal marKin of fou.>h abdomiiiiii HeKment. Abdomen, pyrlform. HllKhtly marKlnate. liorital surface smooth. Antennae, lonK stroiiK. LenKth. 3.42 nmi.; iHt siKment, .3X7 mm.; Vnd segment, 1.267 mm.; 3rd seKment, .».S5 mm.; 4th MCKment, .7S3 mm. Ltga, BtroiiK. clothed with hairs as in preeediuK hiKtars. Hind tiblu ..".•5 mm. Color, pale green; npex of head, marKilis of wings and marKin of thorax yellow; shortly before moulting the wIuk pads become dark brown at the tips. Kyes Kreenlsh white, but seen under the microscope the Inilivlrlual facets appear reddish brown at their centres. Length of Body, 4 mm.— 4.2 mm.; width. 1.62 — I. s.') mm. ADULT. — The adult has been described by Knight (15) as follow.'^; "Lygus communis var. novascotlensis n. var. I'aler and more si -ndf r than the tyi)loiil communis, but not dirferlng materially In the male claxntrs. Breeds abundantly on apple In Nova Scotia; but In New York I have been unable to take any form of communis on the apple. Kength, 5.3 mm.; greatest width 2 mm.; more slender and much paler than the typical communis; the two black rays on the pronotum small but distinct; hemelytra more yellowish brown than fuscous; lateral stripe ot the body reddish or darkened with fuscoua. This Is one of the varieties or races of communis which may be worked out from the forms inhabiting different plants, .ind perhaps Influen'-ed somewhat by different external conditions." 33 METHODS OF CONTROL. Spraying Experimrati in 1916. Control fxpcriiiifiitH wen' iiiDltTtHkcn diiriiiK the scHsor' of 1!)1.'). though iiiiilff inoMt iirifavonthlf coiiilitioiiH, tin- Wfidln-r lifiii^ uliiioNt foiitiiiiioiiHly wet. TIiIh iiiiKic it e inuiii)ers ie|)resent but a very small iH-oportion of the insects origiimlly present on the tree, the dead bodies of which could be loinid in abundance sticking to the leaves or strewn upon the ground. Nevertheless, owing to the vast number of insects present and their tendency to seek out and feed upon the fruit, sufficient escaped to reiidi'r the spraying futile. It is only in the last three nymphal stages that t!ie insect can readily make its way over the grouml and reach the tree. First and second instars are likely to become engulfed in the small openings in the soil, and so perish. Moreover, the voung nymphs do not fall to the ground as readily as they do in the later stages. Mechanical Effect of the Spray. To determine whether the effect of the spray was iiu'relv mechanical, and whether or not it might be possible to control the insect by a heavy spray of water alone, another badly in- fested tree was given a strong spray of water, using a Friend " drive ■■ nozzle and a pressure of 200 lbs. In this case the total count over several days amounted to 308. and an examination of the tree showed that there was no appreciable dimiinition in the number of insects jn-esent. This showed conclusivi''y that the insects do not drop to the ground with sutt'icieiit reid- iness to enable us noticeably to reduce their lumdjer simply by forcing them from the trees by a strong spray. It also showed that there was something besides mere mechanical effect re- sponsible for the large drop from the tree sj)rayed with nico- tine sulphate. The insects at this time were in their last uyn- phal stage, and it may be that many of them were only partially covered with the spray, and accordingly only temporarily ovr- come. It is possible that the effect of the nicotine fumes is to make the insect relnx its hold and Irop to the ground. Some experiments conducted last season seem to indicate that I he fumes of the nicotine sulphate were themselves deadly to ^h>» insect, but later experiments undertaken on a large scale dis- proved this. In any case it is always true that a large nundjer of nymphs fall to the ground, and of these a considerable pro- portion HgHin make their way up the tree. The larger the nymphs the more readily .Joes this dropping occur, and the sooner the spraying is done after they hatch, the smaller the 35 iiiimhtTs tliat will he fouiid niakiii^' their way up the tree. It is obvious, from the fort'^oiiig facts, tliat in' order to e'lntrol this pest sueeessfully, soniethiiijj must l)e done to |»reveii1 tl:e reaseent of nymj)hs wiiieh iuive fallen to the grounxtra team were available to follow behind the sprav machine banding would not be necessary. 36 It was also found tliat wlictlifr banded or not, tlic orchiivd nmst be cultivatt'd, subsequent to si)ra.vinK. in order to destioy tlie weeds and f?rass at tlie base of the trees, as the nymphs are eai)al)le of eonipleting their develo|)nient upon sueli plants. Cases have been noted where tlie jrood efl^'ects from sprayinw and baiidinj? have been rendered w t!)h.ss from the insects fiyiiif? up and attacking tlie fruit aiui ovipositing in the twigs, after having come to maturity on weeds growing in tlie orch- ard. This was found to be particularly true of pears, which are esi)ecially attractive to the adult insects. A row of IJart- lett jx-ars, growing in sod, was cleaned of the insects by care- fully spraying and banding. As soon, however, as the ailults appeared they Hew to the pears in large numbers, as many as IK beijig found on a single small fruit. In this case, many of the bugs came from nearby ai)ple trees, l)ut numbers of them were those that had complet<' *''« «••«!> destroyed to a greater or The trees were i)rune.l as much as was considered safe and where necessary, were headed back to facilitate the action tLZ T'^f' 't ^'"'"f '''"'.' '•^"'^•^''^ ^ith tree tanglefoot and vtkT. rl'" V'"'V\"' '"'^''^"'^ ""*^' *he end of the first In^l fn . ^' V'-'^''l ^'xanunation of the trees showed the hlvh.I h ' Tf .■" '«'-^^'."'"»l'«'-s. as many as twenty- wo hay ng been taken iron, a single blossom cluster while twelve or thirteen were eoi.iriiou, and five or six the general rule. were'^!l?«t"h ^ ^'"■■'^' I''"' ^'""""^'""'^ ^vhen the Gravenstoins leaf 40 1 nt'to T/u7 ," T''' "f"^ '"^"*"'^^ ^"'P*'"*^ (^^l^^k- U at 40) 1 pt. to 100 gals, of regular summer lime sulphur spn.y. The early varieties were sprayed first, our aim being to tr^at Ttr^T'W"^"' -' '"'^ ''' '"''''^^'^ ^'^^^'•^ it ««'"« i»to bloom: ^lori ^h Jllu' "?f '' "'^' ."''"' throughout, and the most thorough work possible was done. This task was rendered recct J"'" '^ '•"' '"""""^ "•"•^" '"^^ *^-« had pre'fously frn,.7r'T'*' ■'" ''"'* '•*" *'"" ^'■'* "I'"**^ »'•« ^»g« began to fall from the tree in increasing numbers and to cluster beneath the ang efoot bands. Only a few, however, actually became en tangled m them as most of them, after wandering ov™r the base of the trees for a few hours, left it for nearby weeds where hey were later destroyed by cultivation. The application of the second spray was commenced when about fourVfifths of the 38 blossom petals had fallen to the ground. The sanu' matei-ials ■vverc us.-d .-xecpt that Hour paste was added as a si)rea(ler ov-r a portion of the orehard. Orchard No. 2.— This is a six aere orehard loeated at Clarenee, Annapolis Co.. and like tlie other was formerly a heavy bearer. l)iit. tiiough only the erop of tiie Nonpareils had been'eomi)letely destroyed, the pereentape of No. 3's and culls on tlie other varieties, hail been growing rapidly. There are S2 Nonpareil trees in tliis oreiiard, whieh in 1911. the tirst year of whieii we have anv reeord. produeed 'mO hhls. of fruit, tins re- dueed in 191.') to about Wj hbis. of worthless euU ai)ples. In that vear. aeeording to the owner's statement, "the horse ate the entile eroi> of Nonpan-ils."' Vhough the owner has been able bv good treatment to maiiuain the erop on the other varieties more nearly at \lie sanu- level than in the ease of the Nonpareils, a large percentage of th ni are so missliai)eu as to be entirely worthless. The iunid)er of :i's and cidls has stead-.iy, with soiiie variation, increased from 40'; in 1911 to 86'/, in 191.'). Though factors othe-- than the b\ig were in part responsible for the production of 3's and culls, their steady in- crease can be largely attributed to this source. These figures do not, of course, take any account of tiie loss in vigor occa- sioned tile infested trees by the work of the insect, which, even with the best of treatment, will take some years to restore. The damage done to tiie trees in tiiis orchard was most notice- able in tiie Nonj)an'ils, as in orchard No. 1. Nevertiieless the damage clone to otiier varieties was rapidly increasing. The sj)raying in this orchard was done on the same pl.-.n as in orchard No. 1, excei>t that soluble sulphur was used in the second bug spray, and the nicotine solution added to tiiis com- pound. A soft tisli-oil soap was added to a portion of this spray to act as a spreader. For this reason we added no arsenical ; but, as tiie bud moth and other biting insects liad been controll- ed by previous sprays, and a' .".;e codling moth is not a serious pest in the locality, we were quite safe in doing this. After the first four days of spraying the bugs began to drop from tiie trees in large numbers, seven hundred being taken from the base of one which was badly infested. These, however, so**!! left the tree for the weeds, where later the cultivator destroyed them. 39 o K n o o CI '^ X <=* O M ^1 ar o -I oi CO Oi < O O H as H •< H CO d « o • ? -= = .a; = ,« S O "O 0) = it CO C' i3 g 1^ 3 0)-:: ;c ■>»' o ■^ * n 50 :c 1* rt t* ■^ 3t ;C I? ;0 X w ^ :c c^ 'J' Ti t- o I M o as n u o ^ -C X o ce a O -♦ 5C p O *C M t>- ^H If? 'yx w^ Vi o >c ri I~ — ■T" , Q o H z ^ O UJ o -1 « QQ 0. < \- Oi o « o 9 S c o c -♦ X c "M t(? a: o M « X r: -^ X ^ o c O C S M S = 3 o H as is H CO t^ W W -i" IC CD ^ — -. -H -H ^ w 03 C5 9& 05 O) -I ^ £j: = H c S c s e o s n •* O "X lO » o> X n n u« S — ® O m 3: X iir OI s; ^ p; -3 3 if O i — ■= c e a I ~ ic t~ X o -"ji ■>»• X X m ^ .^ X i 0 s i:^ O C ■= O O « US IC ~ -» « — »-< (M 50 ** us ^ "5 i « -N -« .M 93 OS Oft OS Oi 03 i » 1 a a 2 8 40 Results of Spraying. The result of our spraying was a sueeess as far as killing the insects was eoiieerned. A few insects naturally escapotl unhaniu'd, as in all field experinu'uts. but their numbers were inconsiderable, and they were unable to cause appreciable damage. The spreaders were found to increase the eff.'ctive- ness of the spray, and to enable the same amount of material to cover considerably more surface. The pears in the spraved orchards were carefully watched as soon as the adults began to appear. The condition of the Vears would form a good indication of the success of the work, since any insects left would be certain to seek out and puncture this fruit. For the first five days after the adults began to ap- pear scarcely a winged bug could be found in either orchard, but finally they began to appear, though in small numbers. It is known that the adults are strong fliers and that they are attracted to the fruit of pear for considerable distances. That these bugs flew in from neighboring unsprayed orchards is made evident by the fa'^t that in orchard No. 1, where the pear trees were scattered all through the orchard, only those on the outside sufl'ered to any extent, those at the centre being piac- ticallv unharmed. The production of perfectly clean pears in infested localities requires the virtual extermination of the pest, not onlv in the pear itself, but in all surrounding apple trees. Though the owner of orchard No. 2 had not picked a ly marketable pears for the past three years, this year fifty-nvo bushels of fine smooth pears were gathered, as well as four bushels, more or less damaged by the bug, but practically all saleable. The chief benefit to these orchards was undoubtedly done by the spray before the blossoms. A careful search was made in both orchards, before the second spray was applied, and it Avas found that scarcely enough insects had escaped after the first sprav, or hatched out afterwards, to warrant the applica- tion of a second. Nevertheless, in order to perfect our work, a second spray was given. Tables number 2 and 3, while incomplete, will give an idea of the crop in the orchards sprayed for the past tew years, as far as records have been kept. It should again be noted that maximum results in crop production cannot be expected until the trees have had a chance to recover from the injury they have received. This is true of orchard No. 1, where the 41 nuii;) ■M • § • t t- o.„ A* § >» ^ X snoaiiBi ~ -|a3»!K " OS I-- qjoK as g £ )(OOHSIlJ_ 1 o-'S o o o i i > spuidy ==^ • o o Siitipog • : "-^ X CO o ■M I r\ ^ fe . & o 3 'J1"IM . -r Z Oi Png 0""' ^ OC X U o -J H CD o 1 ?J ^ [ l-H (IPOt) , - 1- -M ' is o 9|d(?-y " n o X a o ^ 1-^ w l-H n o Si: if ^ Q, n 3[(l(|y •M ^ rl 'f CO iiaajf) " p^ t~ IN ^t iM 50 ^ 8 ^ ^ paiiiiuio imiciiiiy — « X o y; (^ Ml §1 1 it a ^ c: a C3 a 1 ^ -^ — «• -C^aijv^ 'o I' § i 8 2 o pjBqoJo 6 6 6 6 ?5 CI 6 6 'A 42 NciipaN'ils, partictilHrly, wt'ic so wc)tkt'iif from the followiii!? fortnula: Solublo suipliur '^V- lbs. Fish-oil soap (soft) 19 lbs. (Iruilo carbolic acid I I>t- Water 1«0 KalH- To a portion of this preparation wc aiidc*! triplumbio arsenate of lead as a poison. III.) Fish-oil soap (Soft) used in strengths varying from 1-6 to 1-10; both alone and with solid)le sulphur. (IV.) Laundry soap (hard) used as above. (V.) Nicotine sidphate (Hlaekleaf 40) was used in strengths varying from Va pi"t to 1 pint for each 100 gals of spray. It was iised rflone and in eond)ination with lime sulphiir, soluble sulphur and barium sulphur. To a portion of each of these combinali uis flour paste was added as a sprea«ler, ami in the case of the soluble sulphur cond)ination, soap was also test- ed for this purpose. Each separate combiimtion was divided into 2 parts and applied, one using a Friend "drive" noz/le, and the other using a "calyx" nozzle. The results showed that the type of ppnty nozzle employed had a great ileal to 'vs acted as a strong repellent to biting inseit.s- 45 V»iri(»iis cHttTiiillars, offi-n-il Iciivfs covered with tln'se |irea;ip. JitioiiH. refused to f I upon them tiiid so starved to death. \ii «'Xee|»tioii \\nH the (-Hiiker worm (Alsophila pometaria) whuli, liowever, did not feed as readily as upon unspra.vei' h-aves. Tlie soa|» sprays were fairly etVe* tive aj?ainst the "very yonnK insects, itiit when used in the afti-r-hlossom sjiray, did not <.'"''<• as satisfactory results. Nicotine sulphate in the weaker strength used jjave fair results aK»iMst newly hatched insects, and at •' , pint to KM) >cals. was (piite satisfactory for the f.rst spray, when properly applied. It .seemed to work c(pially w.'ll with lime sulphur, barium sulphur and soluble sulphur, pos- sibly with a sliffht advantap' in favor of the latter (ui account of its l)ettcr spreading; (pnilities. Soap made an excellent spreader, enabling the same amount of nuiterial to f?o mucii further. The same iimy be sai ,es and nicotine sulphaie, 1 pint to 1(X) nals. It was lound that we c.mld not K«'t the type of sprav (!«• sired by a lower pressure than 17;") ll)s. Whenever it dropped below that point living' bu^s would lie found after the sprav was finished. The eiricieney fell otl" as the pressure decreaveJl and became j,'re}>ter with the increased pressure, (iood work was doiu- at 17') lbs., but hifrher |>ressures ^ave even bettei- re suits. Hc(ter results were obtained where one man worI< -d with a pressure of L'OO li)s., than where two attemi)tcd to sprav using only I.IO lbs. (d) Spraying Without Banding.— Block y of tices were sprayed and bandtnl iu the '-egular manner, but strip.s of sod or Aveeds were allowed to grow beneath the trees. In such eases injury was done by the adults which came to maturity on these l)laiits, wherever the pest was numerous. Pears sutf'ei"d I'speciaily from their work. This was done in a heavilv infested orchard. Wh.'n tested with a light or moderate infesta;iou, ami aLso in a snudl orchard where tiie sprav could be applied at just the correct period, the benefit from banding way fo'ind to be inconsiderable. 46 CONCLUSIONS FROM CONTROL EXPERIMENTS. 1. Material to Uie. Till- most stitiHfacfory inatiTial to use is iiifotiiif siilpU'itf (Hliicklfaf 40). Thf othl-r matfi-ials .'Xii-riiin'iitrtl with, whili- .•tlVctivf, havf not. at tin- prt'Sfiit cost of lla- raw inatt-rials, any ailvanta^f in <•««< "'kI ">'•' "«'♦ >"» t'onvcnifnt to Mm-. If prop.'i'lv ap|»liti' a sttcnjrtli of ■' | pint for i-ai-li HM) k'hIs. will "jivi' i\- ft'lli-nt results. 2, When to Spray. Tin- idt-al time tor tin- api)li<'ation of tlu" first spray Im when tlif blossoms are sliowinjr pink, preferably after the blossom peilii-els have separated, but before the petals have be- >run to open. I'ntler field comlitions this ideal is ,v- ed by the harrow or eidtivator, this'niijrht do equally well, i>;it a second team is rarely available for this purpose. A vvide heavy band is not nceessary, since these insects c. per tree In none of our work was any attempt nmde to save iimterial, all our efforts being concentrated on the destruction of as tiiiiiiy bugs as possible. Even with this, many may be inclined to ask if the cost is not excessive, in proi)ortion to the eiiil gain -d. Those who have spent large sums on their orchards for years past, in cultivation, fertilizing, underdraining, etc., only to see the crop fall oft" every year until it is finally greatly reduced, if not entirely destroyed, will not be likely to hesitate regard- ing this expenditure. The great ditt'ieulty lies in the fact that the absolute necessity for work of extreme thoroughness is seldom realized when the first attempt to control the pest is nmde. The result is that, not only the crop, but also the money .spent in attempting to produce it, is lost. Where, however, the precautions outlined in this bulletin are faithfully folloAved the cost is inconsiderable when compared with the benefit to be gained. Many growers have now to (;."cide whether they vill have the best of their land encumbered with an unprofitable S3 orchard, or whether they will expend the time and money neceggary to eradicate the pest. 11. CteiMral CoiuidarationB. It will be seen from the foregoing discussion that the con- trol of the green apple bug is no ordinary task. The time con- sumed in spraying for this pest is considerably greater than when It is only necessary to do ordinary work. It is therefore doubly important that the spray pump and engine should be m good order and. that the facilities for filling, etc., are such that no time is lost. Many precious hours are wasted for the want of a little attention to the machine, before the spraying season commences. When the success or failure of a certain spray depends upon getting it on at a certain critical period no precaution should be neglected to prevent unnecessary de- lays. Some orchardists can fill their tank and mix their ma- terial in as short a period as ten minutes, while others require as long as forty-five minutes to an hour in doing the same work. Others have gone to the expense of purchasing a power outfit, but in place of a regulation tank make use of one or two 40 g«!l. barrels. This necessitates the same amount of work for every 40 gallons that it should take for four or five times the amount. Such delays as this make all the difference between profit and loss in spraying the orcliartl. With proper facilities and the use of drive nozzles, a good outfit siiould put out at least 1.000 or 1,200 gals of spray per day, but this will not allow much margin for tinkering vvitii the outfit. 12. Causes of Failure. Numbers of growers have attempted to control this pest without results commensurate with their expenditure and ex- perience has shown that the neglect of some very slight pre- caution is often responsible for such failures. Some have failed to band the trees, others have not kept down the weeds, and these have had tlieii- efforts defeated by the insects which made their way back to the trees again. Many have not done the work with that thoroughness that is an essential to success. It IS hard to make the average sprayer realize the amount of care necessary in order to have the liquid reach every insect. Others, who did the work as well and thoroughly as was pos- sible under the circumstances, failed because they did not secure the right type of spray. These must remember hereafter that with ordinary mist nozzles and low pressures it is next to impossible to control the bug. . 54 Tin- statciiHiit has frequently been iiiadc that tin* coarse spray thrown by nozzles of the «lrive type is i)ro(luetive of wasted material. This type of spray, however, makes it pos- sible to place the spray just where it is required and, if skill- fully handled, should not result in undue waste of material. In fori'inp the liquid into all parts of the tree the outer leaves will naturally shed sonu' of the material, whieh drops to the ground. This must simply be regarded as inevitable, for the man who is afrain definitely proven, both by our own experiments and by the experience of several practical fruit growers. ACKNOWLEDGEMENTS. The author desires to extend his most hearty thanks to ;ill those who have assisted him in any way throughout the course of this investigation. Messrs. H. G. Payne and W. E. White- head have helped in the study of the life history of the insect. Mr. L. Vx. Saunders is responsible for the colored plate and for general laboratory assistance. Mr. V. B. Gooderham assi.sted in the exi)erimental work on various occasions, and most of the photographic work has been performed by him. The success o'' the spraying and other field experiments is largely du" to th. "arnest, i)aiustaking efforts of Messrs. J. P. Spittall and C. F. r. Whitman, who carried on this part of the work. 55 BIBLIOGRAPHY. Owu.g to tl.o fact that the Gm-n Appl.. H„g ,,as only n- cently iHvn .l.-s.-ril,,.,!, and is ap,,an.„tly confined to this part ot North Ainenea. very little has been published n.^anlin- it Ow„.^ to its very elose relationship to the false tar„.s"he,l plant bug (I.ypus eonnuunis Knight), and the similarity of their work, references to this inseet are likewise ineln.le.l. 1. Itm Lintner J. A.-Rcpt. Inj. Ins., N. Y. 3:110. 1885 Describes injuries to pears which are attributej to I pratensis. which are doubtless tho work of communis. 2. 1891 Lintnor J. A.-Ropl. Inj. lus., \. Y. 7:348, 1890 Describes work of C'oleophora sp. to pears statinK in a foot-note that part of the injury was Lbse, Sly found to be n part the work of L. invitus Say. 7") \o doubt the culprit in this case was also communis. 3. 1893 Lintner, J. A.-Rept. Inj. Ins., N. Y. • 288 1891 ^.°i!f .°" K ""'^-^^ '^""'^ '° P^'*''^ by L. invitus Say, whicn is said to be widespread, but not serious. Descr bes w^rk loSuy'Vhi^^ri'.' Vu- '"•^"'"^'■'' "" Pear^ri^'^another ioca]it> which reaas like a (iescription of what we now recognize as the injury of L. communis. 4 1893 Riley, C. V.— Insect Life. 5 18 Note on injury due to Lygus sp. at South Byron. N. Y. 5. mm 6. 194)1 7. 1895 Records injury to peaches which he attributes to Lveus conimun?;. ""'*' "'^'* '"'^^""^ ^^^^ been mrstuken'^^or Howard Dr. L. O.-U. S. Dept. Agr. Ent. Bui. U. S. 30 98 A note recording attack of Lygus invitus on pe-ches the insect sucking tho juice from the young fruits caus- ng them to shrivel. This is said to be the first record of SuainteT' '"^ ''' *°''''- ^"'^ **"^*' the ^Sr ?« Slingerland. M. V.-Cornell Exp. Sta. Bui. 93:221 Note on injury to pears chjiracterlzed by "hard knotty kerne 8. which are so often accompanied by irregular pustular spots or cracks." This injury was attributed t« plant bugs (L. communis?) or the plum curcuHo 56 «. 1910 Parrot. P. J— Ropl. o.' inj. In^. West N. Y. Hort. Soc. Proc. 55:114-11S>. Figs. During 19U9 It was discovered that gnarly pears, the fruit being stunte 1 and irregular in sliape and more or less marked witli liard, eorky spots, was caused by L. invitua Say. In one oidiard 75'; of tlie fruit was damagPd, .fiO' ; being ren' ered ut^ecs!-. The insect referred to ia communis. 9. 1913 Panot, P. J. & Holf kls:, H. K— Tlie False Tarnished Plant Bug as a Poar Pest, N. Y. Agr. Kxp. Sta. Bui. 368. (Plates S; Figs., 7). Tills is a 20-page buret!n containing a brief account of the history, injuries, habits, bio'.ogy and methods of control of Lygus coir.niunis, which is referred to as Lygus invitua Say. A 1 e-;cription of the ci. ^rcnt stages is given and the name, "False Tarnished Plant Bug", Is proposed as « popular name for the insect. 10. 1915 Brittain, W. H. -Kept. Prov. Ent. Kept. Sue'y. Agr. 1914. A brief note regarding discovery of damage done by the Green Apple Bug to pears and applea throughout the Annapolis Valley, N. S. 11. 191."» Knight, H. H.— Ob icrvation on the Oviposition of certain Capsids. Jr. ICc. Ent. Vol. 8. No. 2. : 296-297. Describes the cetails of ovipoaition of a female Lygus ?n- vitU!-. on a pear twig. The insect here referred to Is L. communis and not the invitus of Say. 12. 1915 Brittain. W. H.-7l!c Green Apple Bus. Proc. Ent. Soc. N. S. 1915. So. 1. : 43-47. A summarized account of ob. ervaticns matie regarding the in-stet during the year 1915. 13. 191* Brittain. W. H.— 46th /nn. Rcpt. Onl, En'.. Soc. 1915. (3 Plr.te:-). More exttni'od account of the studici^^ ma-.e regarding this insect during the season of 1915. 14. 191(i Ki!i^;lit, H. H.— Lygus ccmmur.is n. ;>p. C'r.u. Ent. Vol. .\LVIU.. Xo. 10 : 346-r,4S. Original description of the apocies. 15. 191B. Knight, H. H.— Lyj'us cc mmunis var. novascotienajs n. var. (an. Ent. Vol. XLVIIl., No. 10. : 349. Original ilescription of the variety. PLATE IV. Fig. l.-lnjury to tender lea»v.. irlolnal ) Fig. 2 -Mature leaves a. .een when held to the light, .howln. •«ect Of former Injury by the bug. (Original.) *"*'"» PLATE V. Fig. 1.— New growth Injuriously affected by nymphe of the Green Apple Bug. (Original.) Fig. 2. — Apple twige showing effect of former punctures. (Original.) PLATE VI. 2 F.g. 1.-B.o..om. d..troyed by puncture, of th, bu„. PHoto t.K,„ two FIB. 2.-Un.„jur.d fru.t .pur at th per,„d. (Or.a.n., ) ' PLATE VII. Fig. 1.— Fifth stage rympii feeding on young apple. (Original.) Fig 2. — The same seen from the front. (Original.) mmmmm^m PLATE Vlir. ♦ F