MONITORING AND MANAGEMENT OF THE COTTON MEALYBUG, Phenacoccus solenopsis TINSLEY INSECT AND ITS ASSOCIATED NATURAL ENEMIES ON GREEN BEAN PLANTS

Abstract

Field studies were conducted on cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Sternorrhyncha: Coccoidea: Pseudococcidae) which infested green bean plants at Atfih distract, Giza Governorate, Egypt during two successive summer and nili seasons of 2016 and 2017. The population density, activity periods and the effects of some weather factors on P. solenopsis and its associated natural enemies were considered. The obtained results revealed that in summer season the total numbers of alive stages had one peak of activity in the 3rd of July during the first and second seasons (2016 and 2017), successively. While, in nili season the total number of alive stages had one peak of activity in the 3rd and the 17th December, during the first and second seasons (2016 and 2017), respectively. The total effects of some weather factors such as maximum and minimum air temperature (°C) and relative humidity percentage (RH%) showed significantly positive relationship with the cotton mealybug population. During this study, three hymenopterous solitary endparasitoids and four predacious species were recorded. The parasitoids were Aenasius arizonensis (Girault), Anagyrus pseudococci (Girault) and Acerophagus gutierreziae Timberlake (Encyrtidae). The predacious ones were Scymnus syriacus Mars., Coccinella undecimpunctata (L.) (Coleoptera: Coccinellidae), Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) and Orius laevigatus (Fiber.) (Hemiptera: Anthocoridae). In an attempt to control this insect pest specie, eight insecticides namely, mineral oil, lufenuron, chlorpyrifos, malathion, deltamethrin, buprofezin, thiamethoxam and imidacloprid were tested on P. solenopsis and its natural enemies on green bean under field conditions. The obtained resultsindicated that imidacloprid was the highest efficacy against P. solenopsis recording 90.71–89.17% reduction of the insect population after 21 days of application. Also imidacloprid was the highest efficacy against parasitoids and predators of the cotton mealybug. IGRs toxicants (buprofezin and lufenuron) found to be safer to the predacious insects than other tested insecticides.