Elm leaf curl and woolly Elm leaf curl and woolly apple aphid elmleafcurlwooll203patc Year: 1912 ELM I,EA1- CURT, AND AFFILE APHID. infestation from the woolly aphid was rendered impossible. Leaf curl from elm with pupae and alate forms were secured from the south some time before material at the same stage would be available here, and migration tests were made. The winged forms from the elm were caged over seedling apples, and their progeny, growing along creases where the thin bark is scaling back, in the axils of the leaves and on exposed roots of the apple seedlings, covered by typ
Elm leaf curl and woolly Elm leaf curl and woolly apple aphid elmleafcurlwooll203patc Year: 1912 ELM I,EA1- CURT, AND AFFILE APHID. infestation from the woolly aphid was rendered impossible. Leaf curl from elm with pupae and alate forms were secured from the south some time before material at the same stage would be available here, and migration tests were made. The winged forms from the elm were caged over seedling apples, and their progeny, growing along creases where the thin bark is scaling back, in the axils of the leaves and on exposed roots of the apple seedlings, covered by typical flocculent white secretion, are unmistakably the woolly aphid of the apple. (Fig. 448). The colony in the figure just cited was started May 12-13, migrants from elm leaf curl. Their progeny thrived from the first and the photograph was taken May 29, the day on which the first apterous generation on the apple began to give birth to young. On part of the seedlings similar tests were unsuccessful, the nymphs dying very soon or in one case after about two weeks tardy growth. This was probably due to aphid resistant seedlings, the ap- ples from which the seeds were planted being from several dififer- ent varieties, and as is well known all apples are not alike susceptible to attacks from the woolly aphid. Habits. The woolly aphid occurs upon the apple as a bark feeder and is found upon branches, roots, and tender places on the trunk. These insects are covered by a white flocculent waxy secretion given off as fine filaments through pores in the skin and their colonies are thus readily detected by the masses of Fig, 438. Bark colonies ^^i^e 'wool' which renders them of Woolly Aphid on apple. conspicuous. (Figs. 438 and 448.) (From Alwood.) ^j^^ ^^^^^ -^^ ^^^^^^^ -^^^^^ enlargements or galls or swellings, and in the creases of these
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