Efficacy of biorational insecticides against Dubas bug, Ommatissus lybicus (Hem.: Tropiduchidae) in a date palm orchard and evaluation of kaolin and mineral oil in the laboratory

In this study، mineral oil and kaolin as alternatives to conventional pesticide (diazinon) were evaluated to manage Dubas bug، Ommatissus lybicus de Bergevin، in the field and laboratory. In the field experiment، effect of four treatments was evaluated against population density (first and second nymphal stages) and honeydew production (as main damage) of Dubas bug. A single application of each product was applied at the recommended rates. Results showed that kaolin، mineral oil and diazinon were statistically similar in decreasing the population density and damage of Dubas bug. This result makes kaolin and mineral oil as potential alternatives to conventional insecticides in date palm orchards. In the laboratory، mineral oil was effective on egg mortality. In settling choice test، the ability of Dubas bug to discriminate between kaolin-treated and kaolin-untreated leaflets increased significantly over the time and females laid more eggs on untreated leaflets than kaolin-treated leaflets. Results of no-choice test revealed that the leafhoppers could lay eggs on treated leaflets as many as on untreated leaflets.