Biological impact of insect growth regulators (IGRs) on the development of the oribatid mite Scheloribates laevigatus (Acari: Oribatida: Scheloribatidae) in the laboratory

Abstract

The biological impact of insect growth regulators (IGRs) pesticides on ecologically important soil oribatid mites' fauna was evaluated  using life history parameters in Scheloribates laevigatus (Koch) (Acari : Oribatida: Scheloribatidae) , under microcosm conditions. Four  novel IGR pesticides namely, Easo 30% WG (Indoxacarb), Kafrozed 5% EC (Chlorfluazuron), Alsystin 48% SC (Triflumuron) and Klegron 10%  EC (Flufenoxuron) were tested. Laboratory fresh adults were reared on plaster of Paris (9:1) supplied with fungal food treated with  agricultural doses of tested IGR pesticides. There was negligible mortality of individuals in control vessels 3.23%, Klegron 10% EC caused  the highest mortality of 35.16 %, and significantly decreased the longevity of adults to 17.26. The growth rate of S. laevigatus decreased in  IGRs reared vessels with moderate influence of Kafrozed 5% EC and Alsystin 48% SC, while a significantly toxic effect of Klegron 10% EC  on all instars was recorded (P<0.05). Furthermore, fecundity declined to 1.8 /day in Easo 30% WG and 1.1 in Klegron 10% EC than the  control vessels. Chitin formation in adults was decreased and the hard brown exoskeleton looks pale in all reared vessels treated with IGR  pesticides.