Role of Host Plants on the Biological Aspects and Parasitism Levels of Eretmocerus mundus Mercet (Hymenoptera: Aphelinidae), a Parasitoid of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae)

摘要

Impact of the host plant type on certain biological aspects and parasitism level of E. mundus under laboratory and semi-field conditions was evaluated. The parasitoid biological aspects were greatly differed within the host type. Parasitoid life cycle was shorter on squash, followed by common beans and sweet pepper, which lasted 27.6?,?±1.9, 25.9?,?±1.3 and 23.7?,?±1.1 days, respectively. In contrary, female longevity was shorter on the sweet pepper (9.9?,?±1.6 days), followed by the common bean (10.8?,?±1.1 days) and was longer on squash (11.7?,?±1.3 days). Additionally, E. mundus life span and female fecundity were also studied and varied among the studied hosts. Effect of host plants on both colonization of pest nymphs and parasitism percentages, were also evaluated. Greater numbers of young and old nymphs and higher parasitism rates were observed on squash followed by common beans, whereas, sweet pepper was last in this respect. Subsequently, the reproduction and biological characteristics of E. mundus have been shown obviously to be influenced by host plant. Efficiency of releasing parasitoids was greatly affected by host plant type as well as releasing rates. Releasing the parasitoid with constant numbers against various population densities of the pest achieved different pest control levels. Releasing rates of 1:5 and 1:10 (parasitoid:pest) gave good control measures, whereas, moderated control levels were fulfilled with ratios 1:20 and 1:30. Increasing pest densities negatively correlated with good control measures.