Effect of Four Host Plants of the Two Spotted Spider Mite Tetranychus urticae on the Consumption Rates and Reproductive Biology of the Predator Blaptostethus pallescens Poppius (Hemiptera: Anthocoridae)

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Blaptostethus pallescens Poppius (Hemiptera: Anthocoridae) is a potential predator on mites and otherinsects in Maize, Mango and grain warehouses in Egypt. The indirect effect of four vegetable crops; bean (Phaseolusvulgaris), pepper (Capsicum annuum), eggplant (Solanum melongena) and cucumber (Cucumis sativus) as host-plantsof the two spotted spider mite (TSSM) Tetranychus urticae Koch on the consumption rate and reproductive biologywere studied at 30 ±1˚C and 60 ± 10% R.H. The obtained results revealed that the type of plant had a significant effecton the daily and overall prey consumption of all the nymphal instars and total developmental nymphal periods. Thetotal predation rates of all nymphal instars of B. pallescens were higher with bean leaf plant (552.4 mites) than that ofpepper, eggplant and cucumber leaf plants (520.5, 451.8 and 349.2 mites, respectively). The major portion of mortalityduring the nymphal stage occurred during the first instar in all tested host plants and the higher mortality was recordedwhen TSSM fed on mites fed cucumber plant, and the lower one was for mites fed on bean plant. The total number ofconsumed T. urticae nymphs by B. pallescens adult females was significantly different among the four host plants;being higher in bean plant leaves (301.9 mites) and lower on cucumber plant leaves (152.4 mites). Also, the totalnumber of consumed T. urticae nymphs by B. pallescens adult males was significantly different among the four hostplants; being higher in bean plant leaves (158.8 mites) and lower on cucumber plant leaves (105.3 mites). Significantdifferences in adult longevity among the different host plants were observed, the shortest lifetime for females was 17.7days on cucumber, while the longest lifetime (22.3 days) was recorded with bean. The oviposition period was shorteston cucumber (10.5 days) and longest on bean (17.7days). Meanwhile, the greatest total lifetime fecundity (70.0 eggs/female) was observed with bean plant, which was significantly higher than on cucumber plant (22.9 eggs/female). Thesuccess of B. pallescens as a biological control agent of TSSM seems to be strongly affected by the host plants onwhich the TSSM were fed on.