Effect of fungicides on leaf rust, yield and kernel weight of three winter wheat cultivars in Mississippi
M.A. Khan, L.E. Trevathan and J.T. Robbins, Department of Entomology and Plant Pathology, Mississippi State University, Mississippi State, MS 39762, USA.
Five fungicides were evaluated for control of leaf rust, caused by Puccinia recondita f. sp. tritici, on three winter wheat cultivars in 1992 and 1993 to determine how protectant or eradicant fungicides, applied individually and in combination, affected leaf rust development, area under the disease progress curve (AUDPC), yield and kernel weight. Symptoms of leaf rust were observed beginning in April of both years. Disease development was greatest on Coker 9733; this cultivar had the highest AUDPC values and lowest yields with and without fungicides. Except for two treatments, the lowest AUDPC was recorded on Pioneer 2548, which had higher yields than the other two cultivars regardless of fungicide treatment. All fungicide treatments to Pioneer 2555 resulted in increases in yield and kernel weight; eight resulted in reductions in AUDPC. Six of the eight treatments also reduced the rate of disease development. Therefore, cultivars such as Pioneer 2555, considered moderately susceptible to moderately resistant to leaf rust in Mississippi, can be effectively treated with flusilazole, propiconazole or mancozeb fungicides.
Plant Protection Quarterly (1999) 14 (4) 147-150.