In Vitro And In Vivo Control Of Colletotrichum Destructivum O'gara (The Causal Organism Of Cowpea Anthracnose In Nigeria) Using Some Plant Extracts

ABSTRACT

 An experiment was carried out in the laboratory of Plant Health Management Department of Michael Okpara University of Agriculture Umudike to check the effects of plant extracts of U. chainae, C. ferriginea, and N. 1ati/lia on the growth of C. destructivum (the causal organisms of cowpea anthracnose) in Nigeria in vitro and in vivo. The experiment was laid out in a Complete Randomized Design (CRD) with 1 0 treatments consisting of the plant extracts and benomyl (a synthetic chemical) and control combined with two concentrations (30% and 50%) of the extracts. In the in vitro experiment, the organism was inoculated directly unto PDA and treatments applied using the chemicals and water. In the in vivo experiment, cowpea seeds were inoculated with the suspension of the organism before the treatments were applied. The result of this study indicates that the plant extracts were effective against C. destructivum in both experiments. U. chainac extract was the highest in reducing the growth of the pathogen in vitro (47.2%) and in vivo (0.00% incidence), though it inhibited the germination of the seeds irrespective of the concentration used. Results also indicate that treated seeds germinated better with 30% concentration than with 50%. Benomyl, a standard fungicide at 3.3g / 200m1 was used to compare the efficacy of the test plant materials and was found to give the best control (100%) as well as encouraged the germination of the seeds (70%). Basd on the result f this study these plant extracts are recommended as possible alternatives to synthetic seed dressing chemicals. Extracts of C. ftrrigineci gave a good control (44.8%) of the organism and also gave the best germination (5 0%) at lower concentration of 30%.