Effects of different diets on biological parameters of the predatory mite Amblyseius swirskii (Acari: Phytoseiidae)

The predatory mite, Amblyseius swirskii Athias-Henriot is one of the natural enemies of agricultural pests such as the spider mite, Tetranychus urticae (Koch). Pollen, as a food supplement or alternative food source, has a considerable impact on the efficiency of the predatory mite in the biological control programme. In this study, the effect of six distinct diets (one consisting solely of the eggs of T. urticae and the others being pollen of apricot, soybean, sesame, walnut, and date, each mixed with the eggs of T. urticae) on the biological parameters of A. Swirskii was studied. Development from egg to adult, oviposition day, and daily mortality were investigated in 65 replications for each type of food. The results demonstrated that A. swirskii was able to adapt to each of the six tested diets and growth development was considerable with each. Comparisons of the biological parameters among these diets showed that the average generation length, from egg to adult, had significant differences at the 5% level. The fertility life table parameters showed no significant differences between treatments for r(m) (the rate at which a population increases in size in the absence of density-dependent forces impacting the population), (sustained increase in population in one day compared to the previous day), and R-0 (number of progeny of the substituted females per person in one generation). The results showed that the oviposition and survival times of A. swirskii were greatly enhanced by the pollen diets so that a much greater efficiency of this predatory mite in biological control programmes was achieved.