EFFECT OF HERBICIDES ON VERTICILLIUM WILT OF COTTON AND INDUCTION OF PHYTOALEXIN GOSSYPOL PRODUCTION BY HOST-CELLS

Pretreatment of cotton seeds with tested herbicides markedly increased resistance of cotton plants to Verticillium wilt caused by Verticilli um dahliae. The present investigation studied the effect of three herb icides tested on mycelial growth of V. dahliae and induction of gossyp ol synthesis of cotton cells. All herbicides selected had inhibitory e ffect on the mycelial growth of the pathogen particularly at high conc entrations. Prometryn caused a great reduction in the appearance of Ve rticillium wilt disease and was the most effective in controlling the disease. Maximum amounts of gossypol production were also observed in roots and stems of prometryn-treated plants. Protection of gossypol wa s greater in treated and V. dahliae-inoculated than in treated and uni noculated plants.