Evaluation of tomato early blight management using reduced application rates and frequencies of fungicide applications

Field experiments were carried out to evaluate the effect of reduced rates and application intervals of the fungicides mancozeb and azoxystrobin on disease control of tomato early blight. In the spring–summer season, all fungicide treatments were significantly better than the untreated control in reducing disease severity. However, early blight disease severity was not significantly different between the two fungicides, azoxystrobin and mancozeb, treatments, nor was it different among treatment schedules within each fungicide. In the summer–fall experiment, results demonstrated significant differences between mancozeb and azoxystrobin treatments in reduction of early blight disease severity. Early blight disease severity was not significantly different among different treatments of mancozeb. However, all azoxystrobin treatments demonstrated significantly lower early blight severity than mancozeb treatments. Results suggest that lower doses of mancozeb, than currently used, can provide acceptable disease control compared to the non-treated control. In addition, results suggest that application of azoxystrobin might be beneficial in reducing disease severity under high disease pressure.