Bioefficiency of some indigenous biocontrol agents against Rhizoctonia solani causing cowpea seed rot and preemergence damping-off

Abstract

Abstract This study aimed to identify the main causal agent of cowpea seed rot and preemergence damping-off in Kerbala province and evaluate some indigenous biocontrol factors in comparison with biological and chemical commercial products in control of the pathogen. The results showed that the main cause of this disease was Rhizoctonia solani where all isolates of this fungus showed a notable pathogenicity. Moreover, all biological agents examined were found to be effective against the pathogen. The maximum inhibition percentages (100 and 89%) were achieved by the commercial products (Beltanol and EM1) while the local biocontrol agents Bacillus cerus and B. subtilis reached 82.66% and 82.22% respectively. However, the third indigenous biocontrol agent Trichoderma harzianum showed inhibition percentage more than 75% and less than 100%. Additionally, all biological control agents demonstrated a high efficiency in protection of cowpea seeds from R. solani infection. This was through decreasing percentage of seeds rot and pre-emergence damping-off in whole treatments compared with control (the pathogen only). The lowest percentage was reached by B. subtilis and Beltanol (0%) followed by B. cerus (5.6%) then T.harzianum (6.7%) and Em1 (21.7%) respectively. However, in control (the pathogen only) was 50%.