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STUDIES ON APHIDES INFESTING THE POTATO CROP
Author(s) -
DAVIES W. MALDWYN.,
WHITEEEAD T.
Publication year - 1935
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1935.tb07151.x
Subject(s) - alate , myzus persicae , biology , crop , horticulture , agronomy , relative humidity , aphid , toxicology , pest analysis , geography , aphididae , homoptera , meteorology
S ummary .1 Field observations show that migrating alatae are the main source of the initial infestation of Myzus persicae Sulz. on the potato crop. They arrive in quantity, during June and July, from various cruciferous plants on which they have hibernated, or to which they migrated in early spring. 2 In 1934 the main migration at a selected centre occurred during a week which contrasted with other periods, since the wind, which was slight, changed from the north‐west to the south‐east, tbe temperature rose from about 67d̀ F to 80d̀ F. and the relative humidity dropped from 68 to about 30 per cent. 3 The hot, dry conditions not only facilitated flight but also greatly increased the proportion of alatae by causing the cruciferous weeds to wilt and die, when alate forms were produced in abundance. 4 The proportion of alate M. persicae was found to be much higher in a district where virus infection of the stocks had been rapid compared with a district where such was negligible. 5 The proportion of migrating alate M. persicae infected with virus diseases, in a district where the spread is rapid, proved to be particularly small. In eighty‐one experiments involving 1178 alatae only four instances included vectors; possibly only a single vector in each of the four experiments. 6 It is concluded that the introduction of virus diseases into a healthy stock by migrating alatae is slight, but this small amount is subsequently spread by apterous forms moving within the crop.