THE ROLE OF BIOTIC AND ABIOTIC AGENTS IN THE CONTROL OF DAMPINGOFF AND WILT OF BEAN PLANTS

Abstract

A potential of five rhizosphere biocontrol agents (BCAs ) , Acremonium zonatum, Aspergillus niger , Chaetomium globosum , Penicillium herquei and Tr ichoderma vir ide were studied under in vit ro and in vivo exper iments for controlling damping-of f and wi lt pathogens (Fusar ium monil iforme, F. oxysporum, F. solani and Rhizoctonia solani) of adzuki bean (Phaseolus angular is L.) and snap bean (Phaseolus vulgar is L.) . Aqueous neem leaf ext ract 40% and benlate ( fungicide) were tested for compar ison. In vit ro exper iment showed that all the bioagents as wel l as neem ext ract and benlate inhibited the growth of the damping-of f and wilt pathogens with var ious rat ios. T. vir ide causes the highest growth inhibit ion values while P. herquei gave the lowest ones. In vivo exper iments showed that all the BCAs reduced the disease incidence with damping-off and wi lt of both bean var ieties. T. vir ide was the most ef ficient BCA against all pathogens, whi le neem extract and benlate were less effective. Appl icat ion of T. vir ide culture or culture f iltrate by soi l infestation or seed dressing signif icantly reduced disease