Effect of some natural bioagents and natural enemies against aphids in wheat fields

The present investigations were carried out at Ebn-Malen Farm, El-Nobariya region, Egypt during the two succesive wheat growing seasons 2004 and 2005. The entomopathogenic fungi(Lecanicillium mascarium, Nomuraea rileyi, and Paecilomyces fumosoroseus the predator Coccinella undeciumpuncata L. and the ethanolic plant extracts of Atropa belladonna, Hyoscyamus niger and Solanum nigrum were evaluated under laboratory and field conditions aganist the cereal aphids, Rhopalosiphum padi L. and Rhopalosiphum maidis (Fitch). Data showed that the fungus L. Mascarium significantly scored the best results aganist R. padi and R. maidis, followed by P. fumosoroseus, and N. riley. LC(50)s. of the entomopathogenic fungi ranged between 67.5 and 87.8 X 10(5) cereal aphids, Rhopalosiphum padi L. and Rhopalosiphum maidis (Fitch). Data showed that the Fungus L. mascarium, Significantly scored the best results against R. padi and R. maidis, followed by P. fumosoroseus, and N. riley, LC(50)s. of the entomopathogenic fungi ranged between 67.5 and 87.8 X 10(5) S pores/ml for R. maidis and between 69.9-7 1.6 X 10(5) and 88.5 spores/ml, for R. padi. Laboratory results generally indicated that plant extracts enhanced the fungal efficacy. Under field conditions, the treatments with different fungi in presence of the predator decreased the infestation with the two cereal aphids. Application of either the fungi or Plant extracts coupled with releasing of the Predator decreased significant decrease in the percentages of yield loss in both seasons