TOXICITY OF COPPER (1) OXIDE METALAXYL FUNGICIDE AND SELECTED PLANT EXTRACTS TO COLLETOTRICHIUM LINDEMUTHIANUM (SENSU LATO) AND MANAGEMENT OF COWPEA ANTHRACNOSE DISEASE IN NIGERIA

Abstract

In vitro studies were conducted to evaluate the effect of three plant extracts, Datura stramonium, Ricinus communis and Jatropha gossypifolia at 30, 50 and 65% concentrations and Copper (1) oxide in metalaxyl based synthetic fungicide (Trade name: Tandem®) on Colletotrichum lindemuthianum growth characteristics. The plants extracts were applied in situ to assess their efficacy in the management of anthracnose disease on cowpea. The results showed statistically significant (P<0.05) variations in C. lindemuthianum growth depending on the extract and concentrations. D. stramonium at 65% concentration was the best in reducing the growth of the fungus and disease incidence in the field. The effect of 65% D. stramonium compared favourably with the standard application rate of the synthetic fungicide. The growth rate of C. limdemuthianum treated with 65% of D. stramonium extract and Tandem® were not statistically different, both were approximately 2.9 mm day-1. Similarly, disease incidence was reduced by 14% in the plots where either the extract or Tandem® was applied. The study demonstrated that the active compound in the extract of D. stramonium can potentially replace synthetic fungicides in the management of cowpea anthracnose disease.