Effect of Fusarium, Paecilomyces and Trichoderma formulations against aphid Schizaphis graminum.

Fungal strains belonging to the genera Fusarium, Paecilomyces and Trichoderma were tested in vitro in order to study their effects against Schizaphis graminum, one of the major pests of cereal crops around the world. Biological assays were performed using a solid formulation that was obtained from fungal cultures grown on rice and then finely ground (<0.2 mm). The occurrence of toxic secondary metabolites (fumonisin B1 and beauvericin) produced by these fungi was also investigated. In each experiment, three groups of aphids: 15-hour old larvae, 5-day old nymphs with wing buds and wingless morphs were treated with a suspension of a fungal formulation. Some strains belonging to the genera Fusarium and Trichoderma significantly controlled the specimens of the three groups of S. graminum. The F proliferatum strain ITEM 1407, producing a high level of fumonisin B1 in the culture (1250 microg/g), and F larvarum strain ITEM 2139 had high insecticidal activity (>60%) within 10 minutes after application. As F. larvarum ITEM 2139 did not produce metabolites toxic to mammals, it might be a good candidate as a biocontrol agent of S. graminum in the field.