Effect of Leaf Infection by Kabatiella zeae on Stalk Rot Prevalence and Grain Yield of Maize Hybrids

Eight maize hybrids were tested for resistance to eyespot (Kabatiella zeae) and stalk rot (Fusarium spp.) under field conditions in 1993–1995. The relationship between eyespot and stalk rot and their effect on grain yield of hybrids were studied. Effectiveness of the prochloraz fungicide in controlling both diseases was evaluated. The experiments were performed in three subtrials where plants were naturally infected, inoculated with K. zeae or treated with the fungicide, Sportak 450 EC. The relationship between intensity of leaf damage by eyespot and incidence of stalk rot has been evidently confirmed. High infection of leaf by K. zeae reduced grain yield of hybrids. However, considerable differences in prevalence of disease and yield losses were noted in successive years. The intensity of eyespot depended upon environmental conditions highly variable over the years: it was enhanced by low temperature and high air humidity in July and August. Hybrids showed significant differences in susceptibility to both diseases. Mona – hybrid from the USA and two experimental hybrids from Poland were less affected by diseases than Smolimag and Hidosil (commercial hybrids from Poland). The fungicide Sportak was effective in controlling eyespot and had an indirect influence on decreasing fusarium stalk rot.