Intraguild interaction between the entomopathogenic fungus Beauveria bassiana and two aphid predators

Abstract

Entomopathogenic fungi and aphid predators can independently manage Aphis craccivora, Koch (Hemiptera: Aphididae) populations. It is important to assess the risk of possible fungal infections in predators when integrated in Integrated Pest Management (IPM). The virulence of two entomopathogenic fungi isolates, Beauveria bassiana (Balsamo) and Paecilomyces lilacinus (Thom) Samson have been tested against A. craccivora. A laboratory experiment was conducted to study the direct spray effect of different spores' concentrations on the aphid adult stage. The obtained results indicated that B. bassianais was more efficient against A. craccivora according to LC50,1.2×10 7 spores/ml. LC50 of B. bassiana isolate was applied against the second larval instars of both the green lacewing, Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) and the seven spotted lady beetles, Coccinella septempunctata (Linnaeus) (Coleoptera: Coccinellidae). The bioassay indicated that B. bassiana was slightly harmful against Ch. carnea and significantly injurious against C. septempunctata. The total mortality was 13.3 and 43.3% for Ch. carnea and C. septempunctata, respectively. According to the high pathogenic efficiency of B. bassiana on aphids and the low efficiency on the Ch. carnea, the finding suggested that B. bassiana has the potential to be utilized as highly efficient entomopathogenic fungi in IPM programs, in conjunction with the predator Ch. carnea, against A. craccivora.