Side effects of botanical insecticides on predatory mite Amblyseius andersoni (Chant)

The effects of the botanical insecticides Biopiren plus, Piresan plus and Neemazal T/S on the predatory mite Amblyseius andersoni (Chant) were tested under laboratory, semi‐field, and field conditions. The tests carried out in the laboratory allowed detection of the direct toxicity on eggs and females as well as the effects on fecundity, whereas semi‐field trials assessed their residual toxicity. In laboratory and semi‐field tests, pyrethrins, particularly Piresan plus, proved to have the highest toxicity with E value, concerning both female mortality and fecundity, of 100 % and 45 %, respectively. The same product tested in the field only caused a significant reduction in the phytoseiid population shortly after the treatment. The relevant escape rate registered in semi‐field tests could explain the lack of phytoseiid eradication in the field after treatment with pyrethrins.