THE ROYAL CANADIAN ee Gniversity of Maine. ee ; Sag re yee AB KAR pS HON iy ARS th ai H Biological AN G,. & "g Medical \ SA? Serials = Maine Avricultural Experiment St ati ORONO BULLETIN 248 MARCH, 1916 meee, LIFE HISTORIES OF LEAFHOPPERS OF MAINE MAY 15 iyie CONTENTS. PAGE LP DSO PA RSME te a One ames ee 53 Pan eooited-| EAINOPDeh. 2i <7 Bes ees Sao Ss we ws 59 ; meouiy Crown beathopper (05.00.05 or. el OU, 69 Munem G! bt tittiis t. Po ebb SL Oat, oe we on 73 MimopmIeeee TCUNGY 9 Gage les are es hd. 8h 76 Lye ase i SETS ORR 2h ed aa a ea 77 Pr AOU el Ceeeteeed «UIT T OLAS etre a iade sare ogo ~~ Fig. 2. Cicadula sexnotata. a, Ist; b, 2nd; c, 3rd; d, 4th; e, 5th instars of nymph. f, tarsus of a much enlarged. a, b, c, drawn to larger scale than d, e. (Original). LIFE HISTORIES OF LEAFHOFYrERS OF MAINE. 67 Moulting occurred in three days from hatching the 26th of July for the eggs hatching July 23rd, a second moult occurre'l four days later July 30, the third moult on Aug. 3rd, and the fourth moult on Aug. 6th, with final moult and appearance of adults on Aug. 11th, or twenty days from hatching, about twenty-seven days from egg deposition. Allowing a probable week or ten days in adult stage before egg deposition begins would give us five to six weeks as the period of the summer brood and at this rate it would be an easy matter to have three or four generations in a season for the latitude of central Maine The nymphs when first hatched cling pretty closely to the leaf but may crawl around and especially toward the tip of the leaf and the leaf becomes spotted with their punctures. These at first appear white but later change to red and then to black and the leaf in severe attacks will shrivel and turn yellow, in bad cases the whole leaf turning yellow and shriveling, The appearance is shown in the photograph reproduced in Fig. 12. DESCRIPTION OF EARLY STAGES. The eggs as dissected from adults July 1oth and as examined from leaves are slender with a length of .£8 mm and a width of .16 mm narrowing at either end, the head end wider and with a clear space while the remainder of the egg contains minute globules as seen by trans- mitted light. Fig. 1 d. The surface of the egg is smooth the chorion with no apparent markings. Ist instar: The nymphs on hatching are .6 mm to .7 mm long and at end of the instar have reached a length of slightly over one milli- meter. The head is large and rounded in front much produced, half its length, before the eyes. Prothorax about half the length of the head. mesothorax short, transverse, meta-thorax about the length of the pro- thorax the sides slightly extended backward and the hind border slight!y concave. The hind tibiae bear six spines on the hind border and there are six or eight spines on the end of the abdomen and a comb of three or four short curved spines on the end of the sub-anal plate. The antennae reach to base of the abdomen and bear on the third segment the usual bristle. The color is slightly dusky and the moulted skins of this instar have a smoky appearance. 2nd instar: Quite similar to the first but with the head less produced and with fairly distinct transverse bars of dusky color. The hind tibiae have six spines and the terminal segment of abdomen ten or twelve bristles and first tarsal segment of hind legs has two platella. 68 MAINE AGRICULTURAL EXPERIMENT STATION. IQI6. The color is yellow and the dark markings become quite pronounced toward the time for moulting and the cast skins of this instar show very distinct transverse bands. Length 1.2 mm. 3rd instar: In this instar there is a distinct black mark on the margin between the vertex and front at middle and next the eye and traces of dusky markings on the frontal arcs and across the abdominal segments two to seven. The vertex is distinctly shorter than in the preceding instars and the beginning of the wing pads is distinctly indicated on the mesothorax by expansions of the lateral border but on the meta- thorax they are scarcely indicated. Length, 2 mm. 4th instar: The color markings are as in the preceding instar. Head shorter, the wing pads more distinctly developed, those of the meso- thorax exterfding back half way on the meta-thorax and those of the meta-thorax reaching the hind border of the first abdominal segment. Length 2.5 mm. 5th instar: The head is but slightly less produced than in the preced- ing stage and about as in the adult and the black markings are clearly marked. On the abdomen pairs of black transverse spots are distinctly evident on segments four to eight. The spines of hind tibie number about eight. The wing pads of the mesothorax are much longer reach- ing to base of fourth abdominal segment, those of the meta-thorax also longer but reaching only as far as the mesothoracic pads on the base of the abdomen. Length 3 mm. In all instars there is a nearly uniform number of the tibial and ter- minal abdominal spines though there seems to be a general increase in number, those of the tibiae ranging from six or seven in the first instar to eight or nine in the last. The beak extends usually to base of the third coxae. The bristle on the third segment of the antennae persists but becomes less and less evident as it does not increase in size in pro- portion to the other parts. As nearly as can be determined by the season’s observations there seems to be one generation developing in grasslands before July 1st at which time the adults appear in new oat fields. A later generation develops in the oats between July 15th and August 15th and the adults and this generation appear to mi- grate either to volunteer oats or other cereals or to grasslanil. A generation develops doubtless between August 15th and Oc- tcber Ist. The autumn generation possibly deposit eggs which hibernate, although this point has not been determined with _certainty. The field cages showed few specimens of this species and their exact hibernation is a question for this region, It will be seen from the habits indicated that the species cannot be controlled upon quite the same basis as some of the other leafhoppers and especially with reference to their at- LIFE HISTORIES OF LEAFHOPPERS OF MAINE. 69 tacks upon oats the application of direct treatment would be difficult. Any measure, by rotation or other method, that will reduce the development in grasslands adjacent to oats fields will of course assist in reducing the numbers attacking this crop. Since the adults appear on the oats while still small it would be possible to run over the oat fields with a hopper dozer, but this would probably need to be raised somewhat on runners 19 order to give the best results. In autumn the plowing under of stubble land in which volunteer oats may be started and sup- porting the leafhoppers may be an assistance in reducing the numbers, TimotHy CROWN LEAFHOPPER. Acocephalus albifrons ( Linn.) This species was taken at various points in Maine during the collections of the summer of 1913 but the abundance and eco- nomic importance of the species were not appreciated on ac- count of the peculiar habit of the species preventing its collec- tion in the ordinary methods so generally effective for the other species of the group. During the present season it has been found in great num- bers and so many features of interest developed in its habits that it has been studied as carefully as time and conditions would permit. The most novel feature of its life perhaps consists in its al- most subterranean habit, the nymphs, and the adults also in very large part, living beneath the surface litter of the sod and in many cases being found under the earth especially in cavi- ties around the timothy crowns. This habit came to light in connection with a careful digging over of the sod enclosed under one of the cages placed for the determination of the hi- bernating places of grass feeding species of leafhoppers. One hundred and thirteen individuals; nymphs and adults of both sexes, were counted under a single cage eighteen inches square and examination of surrounding space in the same field and other old meadows showed this abundance to be very general. Another feature of interest is the apparent restriction of the species to timothy meadows and so far as all observations 2 70 MAINE AGRICULTURAL EXPERIMENT STATION. Ig16. show a quite close restriction to this one kind of grass. So far no specimens have been found in places where timothy is not present and while it cannot be asserted that it cannot live on other grasses we may confidently assume that this is its prin- cipal food plant. The nymphs and the adult males have a light clay color blenc- ing well with the soil and very different from the females, also very different from nymphs of such species as feed above. The life history of the species appears to follow closely the other species having a single brood each year and which are adapted to rapid development of nymphs during the early summer, Sy as ay RA Lo ey Fig. 3. Acocephalus albifrons L. a, nymph of last instar; b, male; c, female. All enlarged, natural size shown iin length lines at left of each figure. (Original). At the time of the first observations on the species bota nymph and adults were to be found and there is every reason to believe that the adults were the maturing individuals of the seasons brood of nymphs and that they were developed from nymphs that had hatched from hibernating eggs. That the eggs are deposited and hibernate in the fields is shown by the finding of the nymphs and adults in the cages placed in earty spring. There were no dead adults or remnants of their bodies as might have been expected if the adults hibernated and de- posited eggs in spring. The early nymphal stages were not ob- served but the stages observed in June and early July were well LIFE HISTORIES OF LEAFHOPPERS OF MAINE. Zt advanced in development and were probably for the most part in the final instar as adults began appearing in early July. The nymphs of the final instar are 2.3 mm in length for the male and nearly white with black markings. There is a broad central patch on the vertex narrowing behind with lateral bands which merge with the central patch behind the middle, a cross band connecting them in front of cen- ter, eyes black center, light border; pronotum white with narrow black stripes at side and a central spot on front and rear margin divided by white line, meso- and meta-thorax with broad lateral stripes covering most of wing pads and a central stripe divided by a broader white line, two spots on meta-thorax lateral broad stripe on' abdomen to last seg- ment central double stripe terminating on the base of the last segment. The female nymphs are similar to the males but larger about four millimeters long head arid thorax 1 3-4 abdomen 2 3-4 mm width 1 1-4 mm. The black markings on the dorsum are very distinct the central black spot on vertex narrower and a small marginal spot half way from tip to eye, central double stripe broken into black quadrate spots on ab- domen, lateral stripe also of quadrate spots on abdomen interrupted on wing pads. Beneath black on margin of front. Hind legs lined with black, tarsal tips black. Adults were secured emerging from confined nymphs on July 21. The females were darker below than the males and emerged from nymphs that were lighter and larger than the male nymphs. One female taken in the cage July 21 was very light gray but the females are generally dark gray to blackish and assume this color soon after emergence. The dark gray or blackish color is mottled finely with white and toward the end of the elytra these mottlings merge into transparent spots and even become transparent white with black spots and lineations. Emergence in some of the confined individuals occurred on grass blades above ground and in one case the nymph crawled up to a height of three inches above the ground to attach itself © to the grass stem. In one attached an inch and a fourth from the earth the fore legs were attached and the hind legs stretched out backward to the tip of the abdomen, In many cases how- ever and probably as a quite common, if not the usual plan for the species now, the exuviae are found on the ground, In the moulted nymphal skin the dorsal slit through which the adult emerges is so closely drawn together that it is hardly possible to distinguish any break. The hind legs are extende 1 backward, the hind tibiae meeting behind the tip of the abdc- men and the hind tarsi resting side by side. The nymphal skins retain their appearance of the nymphs so completely that they furnish every character necessary for identification. 72 MAINE AGRICULTURAL EXPERIMENT STATION. Ig16, Adults become abundant by the middle of July and from this time forward the nymphs decrease in number rapidly till by the last of July practically all are in the adult stage. The first matings were observed July 30th, the mating individuals rest- ing on grass leaf about one inch from the ground. But little mating was observed however and it appears that this is deferred to late in the season and while oviposition was not observed it is pretty safe to conclude that egg deposition is carried on slowly during late summer and early autumn and that the eggs remain undeveloped till the following spring and hatch, probably in May or early June, reaching maturity in July. CoNTROL. It is evident from the habits of this species that it must be treated in a different manner than most of the common leaf- hoppers of timothy meadows as the fact that it is so completely protected under the grass or even down in the sod makes it difficult to reach by the hopper dozer method. It is also doubt- ful whether it will be as much affected by burning over as some of the other species although this will depend upon whether the eggs are deposited so as to be exposed above ground or well protected down in the crowns of the plants. Exact determination of place of egg deposition is desirable in this connection. There can be little question that rotation is a most effective treatment for the species. There is apparently very little mi- gration of the adults from one field to another and even if some movement should occur, plowing in late fall or early spring would serve to very effectually destroy all eggs. A very good evidence of the effectiveness of rotation is found in the fact that the species has been found only in old timothy mead- ows, the worst cases in fields that had been in grass for many years and that none at all have been observed in fields of only two or three years in grass. Of the natural enemies found with the species it would appear that the spiders must be the most effective as they are abundant in the fields and they work down among the bases of the grass plants where they have excellent opportunities to feed upon the hoppers. LIFE HISTORIES OF LEAFHOPPERS OF MAINE. 73 ACOCEPHALUS STRIATUS Linn, This is one of the species collected in abundance in the sum- mer of 1913 and which it was deemed desirable to follow fur- ther for the purpose of getting life-history details that might be a better basis for the determining of measures for control. It was taken in all parts of the state where collections were made and may be considered as of general distribution but it is found in greatest numbers in meadows and pastures and espe- cially in timothy meadows. There appear to be no references to it as an economic species in American works and so far as I know no studies in this country upon its life-history or habits from an economic standpoint. It has been noted in collections from Canada and the New England states for many years and while a well known European species there is little reason to look upon it as a recent introduction. Fig. 4. Acocephalus striatus. a, young nymph Ist instar (?); b, in- termediate nymph; c, nymph of last instar. All figures enlarged, natural size shown in length lines at left of each figure. (Original). It has been found associated with a number of different plants but the nymphs have been taken especially in grassland usually where there is an abundance of timothy and if there is any very close restriction in food plant this grass is probably its preference, 74 MAINE AGRICULTURAL EXPERIMENT STATION. IgI6. The observations confirm pretty positively the occurrence of but one generation each year the adults maturing in July and living on into the fall with pretty certainly fall oviposition and hibernation in the egg stage. Nymphs were found in good rumbers in our cages placed in early spring which proves hibernation in the fields and the absence of any signs of adults either dead or alive shows pretty conclusively that eggs are laid and adults die in fall. Furthermore the development of eggs had reached such a stage in August that it would indicate fall Oviposition. The first nymph observed was taken at Eliot on June 26th apparently in the first instar and at Orono young nymphs (fst instar) were taken July 2nd. One in 2nd instar on July 1st and these would indicate hatching in late June probably as early as June 2oth for all the southern part of the state. The nymphal stages are passed rapidly as the period betweci the first noticed nymphs and earlier adults is but about four weeks. The first adult observed in the fields at Orono was taken July Ist, a male, and these became fairly plenty by the middle of the month. The females mature a little later, the first taken July 18th, than the males but no mating was seen until after August 8th. The latest nymph observed was one in last instar on Aug. 8th. The greatest abundance of nymphs occurred during the first week in July when the different stages were all pretty well represented in field collections, By July 28th adults of both sexes were abundant and scarcely any nymphs were to be found. DESCRIPTION OF NYMPHS. The youngest nymphs found were two millimeters long and were probably first instar individuals but partially grown. They are green in color with outline of the adults but quite different in color, the grass green color of the upper side is flecked with black dots. Below fainter green. The second stage nymph observed (2nd instar) is three and one-half millimeters long of very much the same shape as the earlier form but with a slight indication of the formation of wing pads in enlargement of the lateral parts of meso- and meta-thorax. The color is grass green tinged in places with yellowish and above flecked with black dots which are most numerous on the posterior part of the meta-thorax. Beneath there are dots on the face very scant ®n LIFE HISTORIES OF LEAFHOPPERS OF MAINE, 75 the clypeus and there are scattered dots on the legs mostly on the upper side. The face is distinctly roughened in places, the hind tibiae have two rows of strong spines, nine or ten in each row, and the hind tarsi have two platella on first joint, three ventral. The last instar (3rd) is six millimeters long and longer in propor- tion than the earlier stages the sides distinctly parallel the wing pads of meso- and meta-thorax well developed extending back on to the base of the abdomen to the 2nd segment. The color is green a little paler than’ for the earlier stages and the flecks of dark dots are less evident, being smaller in proportion than for the younger nymphs. The nymphs are very easily distinguished from the larvae of other leafhoppers by the flattened bodies and the rather sharp margin of the head with the parallel sided form of the abdo- men. They have more the general appearance of the nymphs of Gypona than for the strict jassid genera. The figures will assist in recognizing the species in the early stages. The habits of this species differ somewhat from the typical leafhoppers as they seem adapted to living on the ground or close to the surface though by no means so specialized in this tegard as the Acocephalus albifrons. The larvae creep around on the ground very commonly but will be found also on the stems of the plants or even well up on grass blades but they do not jump so readily as some species and while taken in fair numbers in the sweep net the numbers caught in this way are not as good an index of the abundance of the species as for many other kinds, Their color is well adapted to protect them in the grass and they may very easily escape notice unless one is looking especially for them, The adults also run around very commonly on the ground but climb up on the stems of plants readily and are taken in abundance in sweeping. At first light green, they change to shades of gray or dull straw color fitting in well with the color of dead leaves and stems. In both larval and adult stages therefore they are admirably fitted to escape attention of the casual observer and it is not at all strange that they have not been associated with the falling off in the hay crop that is noticed in old meadows. Their attack is made on stems and leaves but for the young especially it is probable that they work at the base of the stems or even down on the crown which offers a juicy point of attack. 76 MAINE AGRICULTURAL EXPERIMENT STATION. IgI16. Since this species has been found in every timothy field of over two years standing and in many cases has been found in great abundance it must be credited with a considerable share in the drain caused by leafhoppers. Its most serious attack must naturally occur during the growth of the larvae from the middle of June to the middle of July, which coincides with the time when the hay crop should be making its most rapid growth. SUGGESTIONS FOR CONTROL. Evidently the most important feature in control for this species is the rotation of crops and, since the species seems to migrate less readily than some of the other forms, this should be effective on fields that are not allowed to remain in grass for more than three or four years. Since the species hiber- nates in the field and in all probability is represented in the egg stage in stems or leaves of grass, burning where this is practi- cable should be effective. The insects do not jump quite as readily as some other forms and might not be collected as com- pletely by the hopper dozer as with some other forms but a proportion could be secured in this manner and, if the process is used for the leafhoppers in general, it would assist in reduc- ing their numbers, CHLOROTETTIX UNICOLOR. This species was noted as quite abundant, especially in low ground and on the rank grasses in the southern part of the state. It is one of the largest of the leafhoppers and when occurring in abundance must occasion considerable loss. Its life history has not been traced entirely through the year but the nymphal stages have been observed and a description and figure will assist in further recognition of the species. Tne nymphs observed were evidently in the final instar and have the length of 8 mm. They are light green in color closely matching the color of the grasses on which they occur. The wing pads are yellowish and extend on to the basal segment of the abdomen. The head is somewhat fuller than in the adult stage, and the abdomen tapers from near the base to quite an acute tip. The nymphs occur most abundantly in July and dur- LIFE HISTORIES OF LEAFHOPPERS OF MAINE. NI Ni De my bot pd at SSRI? Wp = ? x es: SNE = sa SN pi A nrerees a eee % ——t Fig. 5. Chlorotettix unicolor. a, adult female; b, nymph, from pho- tograph; c, adult female; d, nymph, last instar; e, genitatia of male. (Original). ing July and August adults appear in abundance and in the latter part of the season adults only are observed. It seems probable that a single generation for the year is the rule for the species in Maine but this can not be stated with certainty. IDIOCERUS PROVANCHERI. This species recorded as occurring in bogs was collected in July in both nymphal and adult stages. A wider description of the nymphs may be of service in further recognition of the species. i. es gs ~ > Gj — Set % it . ‘ss oe 4 3 PN 4 fr 2 4p 44 ay 2%. ; \ > Fig. 6. Idiocerus provancheri. a, male; b, female nymph of last in- star. (Original). 3 78 MAINE AGRICULTURAL EXPERIMENT STATION. IgI6. The female nymph of the final instar is 4 mm, long and the head 1 1-2 mm.; the abdomen narrower at base but wider than in the male. The color observed is brown with the vertex yellow and the pronotum yellowish or tinged with yellow; the wing pads brown with the sternum and disc of the venter yellow. There is a pair of round black spots on the vertex in the male and the length is the same as for the female. The general appearance is similar but the abdomen is much more slender and with genital processes much more elongate. The abdomen is much restricted at the base, appearing almost wasp-like and leaving a wide space between its margins and tips of the wing pads. The color in most specimens agreed with that of the females but 111 One specimen was jet black above and on the base with light yellow on the sternum and disc of the abdomen, otherwise agreeing with the other nymphs. These were collected rather sparingly on July roth, eight nymphs and twenty adults both were beaten from small bushes in the bog and all the nymphs taken at this time were in the 4 mm. stage. It is quite evident that this is the last instar as no forms intermediate between these and the adults were found at the same time and place. They approach more closely to the nymphs of maculipennis than to any other species. DRAECULACEPHALA ANGULIFERA Walk. The nymphs of this species agree in color with those of D. mollipes but the head is distinctly shorter, the front angle not sharper than a right angle and the dark greenish stripes of the dorsum are different, A pair of dark lines run from near the tip of the vertex to the base of the terminal segment of the abdomen. These enclose a distinctly light dorsal line and out- side of the dark stripes, the upper surface is light green. The frontal arcs are quite distinct and both vertex and front slightly tumid. Length of the specimens noted and figured is 6 mm. The nymphs of this species occur during summer and no indication of more than one brood has been noted. LIFE HISTORIES OF LEAFHOPPERS OF MAINE, 79 Fig. 7. a, Draeculacephala angulifera, last instar nymph; b, Phlepsius apertus last instar nymph. (Original). : PHLEPSIUS APERTUS Van D. The larva referred to this species is quite broad, flattened anil with a rather strongly produced vertex. The color is light clay to whitish and there are two broad stripes on the vertex about equally wide on the prothorax, narrower on the meta- thorax and extended as narrow lines on the abdomen to the terminal segment. They are lighter than the vertex, black on the meso- and meta-thorax and abdomen. A broad marginal stripe covers the sides of the thorax and the narrower stripe and lateral border extend from base to tip of abdomen. Length 5 mm. Two specimens of this have been secured, one of them At- gust &th in timothy mea‘low and from its characteristics it is referred somewhat doubtfully to the above species, although it was not possible to rear specimens to the adult stage. BALCLUTHA PUNCTATA Thunberg. This species is very widely distributed and was mentioned in a previous Bulletin as one of the common forms. It has been taken especially upon Canadian blue grass and during August was found in all stages and while the life cycle has not been followed in complete detail it would be useful to furnish de- scription and figures of the stages observed. 80 MAINE AGRICULTURAL EXPERIMENT STATION. IQI6. % MP Fig. 8. Balclutha punctata. a, b, c, d, Ist, 2nd, 3rd, 4th instars. (Original). The first instar is I mm. in length and there is no indication of wing pads. The head is produced in front of the eyes; the face is dark and the abdominal segments dusky with the sutures lighter, below red with legs dusky. The second instar is I 1-2 to I 6-10 mm. The general color yellow- ish to light brown streaked with red; face not dotted; the vertical seg- ment slightly produced with faint dusky patches in a medium row on the ventral side of the abdomen. The head is nearly a semi-circle in front of the eyes. The meso-thorax has distinct angles but is not pro- duced into enlargement of wing pads; meta-thorax with sharp hind border, no pads. The third instar is 2 mm. or more, light yellowish near transparent color, the sutures below lined with red, the wing pads partly indicated and angles with the meso- and meta-thorax. The fourth instar is 2 3-4 to 3 mm. in length; color light brown to dusky; the wing pads developed so as to reach on to the first abdominal segment. Those of the meso-thorax do not extend to the tip of the under ones. The fifth instar is 3 1-2 mm. to 4 mm.; color differing, some speci- mens being distinctly light green and others brown with red; the face and body above, the legs and ventral surface with dusky patches dotted with fuscous points. The wing pads reach to the 3rd abdominal segment, the front ones extending as far as the hind ones. In the female, two lobes and the ovipositor show distinctly and in the male, plates and geni- talia. aN Fig. 9. Above timothy meadow at edge of cut swath showing at a, height of normal or healthy plants; at b, height of aborted or stunted plants with blasted or imperfect heads; c, cages in meadow for testing hibernation; d, cages on Experiment Station grounds used for rearing leafhoppers and froghoppers. (Original). Fig. 10. Timothy from same field; a@ normal or healthy, b, aborted or stunted stems with blasted heads. (Original). se ee = a a. Fig. 11. Cicadula sexnotata. Moulted skins a, b, c, d, e, Ist, 2nd, 3r:J, 4th, 5th, instars, d, and ec, are on smaller scale than the others. (Original), a Weed %, 4 be a v4 ae ve 1 nd i 3) marc, ‘ CF ~~ "es wv , .e ¥ PERI val Fig. 12. Eggs and feeding punctures of Cicadula sexnotata. Opposite a, egg depositions; opposite b, feeding punctures; opposite c, eggs slightly developed; d, embryo well advanced; e, withered outer part of blade. a and b, photographed by reflected light, c and d photogiaphed by transmitted light to show eggs within leaf. (Original). ree ¢ - } Fig. 13. a, b, males. c, d, females. Acocephalus albifrons: e 3 £ 2 nymph and g to j males, k to n females showing varieties of Acocepha- lus striatus, (Original from photographs by Hammond).