548 EXPERIMENT STATION RECORD. 



The report contains a record of life history studies, together with a short 

 historical account of the part this insect has played as an enemy of the grape- 

 vine in other grape-producing sections of the United States and Canada. A 

 detailed account is given of its habits and destructiveness, the kinds of reme- 

 dies that have been devised for its control, and the nature of the spray equip- 

 ment and spray material which, in recent experiments, have proved most effec- 

 tive in holding the pest in check. 



The life history studies reported show that there is only one full brood of 

 nymphs a year in the region of the Great Lakes. Field experiments prove con- 

 clusively that this pest can be controlled by spraying against the nymphs with 

 tobacco extract solution. 



" In the vineyards of Ohio, west of Cleveland, and in the vineyards of Michi- 

 gan another species of grape leafhopper, T. tricincta, is the predominant and 

 destructive species. The life history and habits of this species, however, are 

 so nearly identical with those of T. comes that the remedial treatment recom- 

 mended for the latter can also be used with success against the former, namely, 

 the application of the tobacco-extract spray to the nymphs at the time they 

 appear in maximum numbers upon the underside of the grape leaves, which 

 for these States is during the last few days in June or very early in July." 



A 4-page bibliography of the more important literature Is appended. 



Woolly aphid of the apple (Schizoneura lanig-era), Edith M. Patch {Maine 

 8ta. Bui. 217 {1913), pp. 1113-188, pis. 6)^-A further report of studies of this 

 pest (E. S. R., 28, p. 251), based upon observations made In 1913. 



While the author has not as yet observed the return of the fall migrants to 

 the elm under outdoor conditions, she has repeatedly during 2 years observed 

 the spring migration from elm to apple and mountain ash and the subsequent 

 development of the summer colonies so that there is no doubt that the species 

 returns to the elm for the deposition of the winter eggs. 



" On the elm the stem mother, which hatches from the overwintering eggs 

 sheltered probably in rough crevices of the bark, appears early in the spring 

 and may be found in Maine before the middle of May stationed on the partly 

 opened leaf buds. The beak punctures on the rapidly expanding new leaves 

 cause an unevenness of growth which forms a protection for the aphid. By 

 the last of May the earliest of these wingless stem mothers are mature and 

 found in the deformed elm leaves producing the next generation. . . . These 

 nymphs, like the stem mother, are a wingless form and they become fully de- 

 veloped about June 10. . . . Their progeny are the third generation and 

 attain wings. These winged aphids are known as the spring migrants. It 

 takes 3 weeks or slightly more or less, beginning about June 20 for all the in- 

 dividuals of this third generation to get their growth, so that the migration 

 covers a considerable period. . . . During this time these winged aphids may 

 be found alighting on the leaves of apple, mountain ash, and hawthorn. They 

 creep to the underside of the leaf and remain there while they give birth to 

 their progeny (i. e., the fourth generation). These young, before they feed at 

 all, crawl to the stem of the water shoots, or to some tender place on the bark, 

 often near a pruning wound, and there start the colony on the summer host 

 plant." 



" There are apparently three summer generations of progeny of the elm leaf 

 migrants upon the apple in Maine, two apterous generations followed by a 

 generation part of which, the fall migrants, become winged and leave the apple, 

 and part develop into apterous forms and, remaining on the apple, give birth 

 to nymphs which while still young seek protection at the base of the tree for 

 the winter and are known as the hibernating nymphs. It is the function of 



