Effect of Milcurb (Dimethirimol) and Morestan (Quinomethionate) on the Control of Powdery Mildew of Cucumber

Abstract

Greenhouse and field experiments were conducted to control powdery mildew of cucumber with Morestan and Milcurb. In greenhouse experiments, Morestan was used as foliar spray at weekly intervals for 5 weeks at the rate of 250 and 500 ppm; whereas, Milcurb was used as foliar spray for 3 times at two week intervals at the rate of 200 and 500 ppm, and as soil drench applied twice at a one month interval at the rates of 500, 1,000, 2,000 ppm.
In field experiments, Milcurb and Morestan were used as foliar sprays once every two weeks for 3 sprays at the rate of 500 ppm. Soil application with Milcurb and Mores-was done twice at one month interval at the rates of 2,000 and 1,000 ppm, respectively.
In greenhouse experiments, Milcurb applied as soil drench gave significantly higher disease control than that obtained by foliar sprays in decreasing number of powdery mildew lesions per individual and total number of infected leaves. However, spraying with Morestan was equally effective in controlling the disease compared with Milcurb soil treatments. Phytotoxicity was observed upon foliar spray or soil treatments with Milcurb at the rates of 1,000 and 2,000 ppm, respectively.
In field experiments, soil application of Morestan completely failed to control the disease. Morestan foliar spray, gave significant reduction in disease severity. Milcurb used as soil drench or foliar spray proved to be the most outstanding in controlling the disease. Phytotoxicity resulting from soil treatment with Milcurb at the rate of2,000 ppm was observed.