Use of entomopathogenic fungi and insecticide against some insect pests attacking peanuts and sugarbeet in Egypt

Abstract

Larvae of Spodoptera littoralis, Spodoptera exigua and nymphs of Aphis craccivora were treated with four compounds, the entomopathogenic fungi (two commercial products Biosect, Biover) and the bacterium (Dipel 2x) and one insecticide (Lannet). These compounds were sprayed on the insects attacking peanut (Arachis hypogaea) weekly. A significant decrease in the population of S. littoralis larvae was recorded after one week from the application among first and second instars. The first instar reached zero in all treatments compared with control (309 control was 3.9 larvae/day on the same date). Larvae of S. exigua was markedly decreased by using Biosect, Biover, Dipel 2x or Lannet. Nymphs of A. craccivora decreased from 64.6 to 0.1 nymph/day after seven days from spraying Biosect, while it decreased from 72.0 to 0.6 nymph/day by using biover, and decreased from 69.8 to 0.0 nymph/day by using lannet while the population stayed between 60.8 before application and 72.8 nymph/day after seven days from spraying.

Suspensions of Metarhizium anisopliae was prepared by harvesting spores with distilled water. The concentration was calculated using hemocitometer slide (3.5 × 10⁷ spores/ml). Commercial (3.5 × 10⁷ spores/ml) suspension of Beauveria bassiana was used for dusting and spraying in distilled water. Studies were carried out in both the laboratory and field. The entomopathogenic fungi showed a high effect on P. mixta either in the laboratory and field experiments.

Keywords:

• Spodoptera littoralis
• Spodoptera exigua
• Aphis craccivora
• Pegomyia mixta
• entomopathogenic
• fungi
• peanut
• sugar beet

Acknowledgements

This study has been financed by the Egyptian Academy of Science and Technology through the project ‘Use of microorganisms and their application in pest control’.