Document Type : Original research articles
Author
Animal Pest Unit, Plant Protection Department, Desert Research Center.
Abstract
Biological aspects and thermal requirements of Euseius scutalis (Athias-Henriot) fed on Tetranychus urticae Koch, Eutetranychus orientalis (Klein), Bemisia tabaci (Genn.) and date palm pollen were studied under laboratory conditions. The female life span duration was (35.3, 29.95, 22.6), (40.1, 29.9, 21), (38.7, 30.9, 22.8) and (41.9, 29.9 20.6) days when fed on T. urticae, E. orientalis B. tabaci and pollen at 20, 25 and 30oC, respectively. Corresponding developmental rates were 0.028, 0.033and 0.44 on T. urticae, 0.025, 0.033 and 0.048 on E. orientalis, 0.026, 0.032 and 0.044 on B. tabaciand 0.024, 0.033 and 0.049 on pollens per day at same temperatures. These rates were fitted to linear equation with R2 of 0.958, 0.98, 0.975, and 0.984. Male developmental times, rates and thermal requirement for development were very similar. Fecundity per female was 32.8, 38.5, 44.2; 27.2, 35.6, 28.2; 31.4, 24.6, 17 and 31.8, 33.8, 44.4 eggs/female over tested temperatures and diets, respectively. Pollen recorded lowest thermal requirements for E. scutalis different stages with highest daily ovipostion; while T. urticae recorded the highest (especially for females) with similar total fecundity with pollen. Obtained results suggest that the best food source for the E. scutalis was pollen followed by T. urticae then E. orientalis and finally B. tabaci. The best tested temperature was 30°C. The wide range of food sources and temperature range may explain the wide spread of this phytoseiid predator in the Egyptian agricultural environment where it is found on most plants. Enhancement of occurrence of this mite over different plants may reduce to some extend the need of applying pesticides.
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