Life History of Euseius Scutalis Feeding on Citrus Red Mite Panonychus Citri at Various Temperatures

Abstract

The aim of this study was to determine the biology and reproductive potential of Euseius scutalis (Athias-Henriot) (Acari: Phytoseiidae) at various temperatures. These data are of value in relation to mass rearing and the development of population dynamics models. The development time, survival and fecundity of E. scutalis were determined at 20, 25 and 30 +/- 1 degreesC, 65 +/- 10% RH and 16:8 photoperiod. Total development times of E. scutalis were 6.7, 4.9 and 4.2 days at 20, 25 and 30 +/- 1 degreesC, respectively, using a diet of all life stages of the spider mite Panonychus citri (McGregor) (Acari: Tetranychidae). In general, preoviposition and postoviposition periods of E. scutalis were shortened as temperature increased, but the oviposition period was longer at 25 degreesC than at 20 and 30 degreesC. The shortest survival time of E. scutalis, at 30 degreesC, was 10.1 days, followed by 23.7 days and 28.6 days at 20 and 25 degreesC, respectively. Mated females laid on average 1.1, 1.4 and 1.7 eggs per female per day and 21.5, 39.7 and 17.1 eggs over their entire life time at 20, 25 and 30 degreesC, respectively. The sex ratios of E. scutalis were 2.11/1, 2.24/1 and 2.11/1 female/male at 20, 25 and 30 degreesC, respectively. The intrinsic rate of natural increase (r(m)) increased with rising temperatures from 0.166 at 20 degreesC to 0.295 females/female/day at 30 degreesC. The net reproductive rate (R-0) was highest at 25 degreesC (26.03 females/female) and lowest at 30 degreesC (12.95 females/female). Mean generation time (T-0) was longest at 25 degreesC (17.50 days) and shortest (9.53 days) at 30 degreesC.