INFLUENCE OF FLUCTUATING PATTERN OF TEMPERATURE ON THE BIOLOGY OF THE PREDACIOUS MITE PHYTOSEJULUS PERSIMILIS ATHIAS-HENRIOT

A.Y.M. EL-LAITFIY
Acarology Unit, Plant Protection Dept., National Research Centre, 12311 Dokki Cairo , Egypt

ABSTRACT

The present investigation aimed to study the biology of the predatory mite Phyroseiulss persimilis Athias-Henriot under temperature which would prevail in spring season in protected cultivation in Egypt . P. persimilis was reared on a daily regular fluctuating temperature i.e. 39-41'C for six hours, then temperature was decreased gradually to 22 ‘C for 18 hours. Relative humidity in the rearing incubator varied between 50-85% according to temperature. Eggs of P. persimilis developed to the adult stage after 3.35 and 3.6 days for adult female and male respectively. The daily oviposition of adult female averaged 2.87 eggs per female. Immature stages of the predatory female and male consumed 17.0 and 10.33 eggs of the prey Tetranychus urticae Koch respectively, before maturity, while the daily consumption of adult female averaged 29.7 eggs. This study revealed the adaptability and efficiency of P. persimilis as a biological control agent of two spotted spider mite T. urlicae under the temperature pattern used herein.