Isolation and identification of some Fungi caused Broad bean root and crown root disease by some plant extracts and Bioagents Trichoderma viride in

Abstract

A field survey was conducted in 15 Broad bean plant fields in Babylon province/Iraq in growth season 2014 this survey was to evalnate the incidence and severity of root and crown rot disease on Broad bean crop. The results showed that the disease was faund in all studied fields with varions incidence (between 40 to 100%) and severity between (26.7 to 75%). Additionally,the The results of isolation and indentification of the disease pathogens domenstreted a Variation in presence of different causal agents. For example,the pathogens Rhizoctonia solani , Fusarium solani and Macrophomina phaseolina wer the most existion in whole tested fields. Also, the molecular diagnosis of these three fungal pathogens using Polymerase Chain Reaction test showed that 12 isolates were belonging to R. solani and 9 isolates to M. phaseolina. However, tow isolatesof F. solani were not detected while 10 isolates were detected clearly. The pathogensity test of these three fungi showed a variation in germination prcentage of tested seeds and differentiontion in disease severity.As well as, the chemicals detection test of three different plant extracts (Cocklebur, Albizzia, Redrot pigwed) indicated to exiting active compounds that were capable in inhibiting the three pathogens growth. The extract of Cocklebur plant was the most effective one by inhibiting percentage F. solani (100%), R. solani (91.47%)and M. phaseolina (88.17%).furthermore, the bioagent Trichoderma viride showed high efficiency in inhibition of the three cusal agents .