Portal de Periódicos da CAPES

Weight losses of groundnuts (Arachis hypogaea L.) from infestation by the mites Acarus siro L. and Tyrophagus putrescentiae (Schrank)

1976; Elsevier BV; Volume: 12; Issue: 2 Linguagem: Inglês

10.1016/0022-474x(76)90031-x

1879-1212

E. Žd’árková, M. Reška,

Plant Virus Research Studies

Abstract The weight loss in groundnuts caused by feeding activity of the mites Acarus siro L. and Tyrophagus putrescentiae (Schrank) were determined. Small amounts of groundnuts of initial weight about 2 g were infested with 10 pairs of (one-day old) mites, and changes in numbers of the developing population together with the changes of the weight of the substrate were recorded for a 3 months period. In A. siro the population grew exponentially till the end of the period when it amounted to 16,500 individuals. The mites consumed 345.5 mg of the food during this period. Calculations of the mean daily consumption per mite gave values 12 μg, 3 μg and 0.2 μg for respective days 21, 30 and 90. T. putrescentiae reached its maximum (8000 individuals) after 2 months and then declined to 1000 individuals at the end of the 3rd month. During that time the mites consumed 559.2 mg of the food. Mean consumption per mite per day was 6 μg and 0.4 μg for day 21 and 60, respectively; as the population declined the mean consumption rose again to 6.5 μg/mite/day on day 90. Thus, on a limited amount of substrate the mean consumption of one individual appears to be indirectly proportional to the number of individuals in the population. Since the weight of one mite ranges from 6 to 8 μg, under optimum conditions, one individual can consume daily at least its own body weight in food.