EVALUATION OF PENICILLIUM-CHRYSOGENUM AND ITS ANTIFUNGAL EXTRACTS AS POTENTIAL BIOLOGICAL-CONTROL AGENTS AGAINST BOTRYTIS-FABAE ON FABA BEANS

Antagonistic fungal isolates (AP1.S20, AP2.R16, Z1.S23 and AP2.R19), f rom root and soil samples of faba bean crops, inhibited mycelial growt h of Botrytis fabae in vitro by up to 44.9%, producing clear inhibitio n zones. Spore suspensions of isolates AP2.R16, Z1.S23 and especially AP1.S20, significantly reduced the development of chocolate spot lesio ns on bean plants in the glasshouse. These isolates were identified as Penicillium chrysogenum. The cell free culture filtrate of AP1.S20 wa s screened in vitro for antifungal activity using four solvent extract s: ethyl acetate, chloroform, hexane and petroleum ether. The ethyl ac etate fraction gave the largest inhibition of spore germination (95.7% ), while the petroleum ether fraction significantly reduced germ-tube extension to 19% of the control. Thin layer chromatography of these so lvent extracts displayed up to 15 discrete fractions from each solvent sample. On application of these to tlc plates, the germination of B. fabae conidia was inhibited at one discrete spot from each solvent ext ract, each with the same R(f) value. Preliminary results using detache d leaves showed that both the culture filtrate and a spore suspension of isolate AP1.S20 significantly reduced lesion development and lesion spread.