Assessing the effect of spraying intervals and different fungicides on late blight management in Wakiso district Uganda

Abstract

Tomatoes are an important source of income, food security for the farmers and an important horticultural foreign exchange earner in Uganda. Late blight caused Phytophthora infestans (Mont.) de Bary is a serious disease of tomatoes that can cause up to 100% loss. Farmers use different fungicides at varying spraying intervals to control the disease. This research investigated the efficacy of common fungicides at two spray intervals in controlling late blight, and their effect on yield parameters variety Tymoti F1 in MUARIK, Wakiso district Uganda. The fungicides tested were Harvestor XL, Victory, Toplite, and Indofil plus a control. Spray intervals of 7 and 14 days were used. The results showed that plots sprayed with Indofil showed the lowest incidence (22.2%) and severity (1) followed by Toplite (22.4%, 1), Victory (30.3%, 1), which were significantly different (P<0.001) from control (66.1%, 2) and Harvestor XL (67.2%, 2). Spraying intervals of 7 days had less disease (26.6%, 1) compared to 14 days interval (56.7%, 2) and were significantly different (P<0.001). Although there was no significant difference in yield from plots with various fungicides, these plots had higher yield than the unsprayed plots. Highest yield was obtained from Victory (31.4 tons/ha), followed by Indofil (29.5 tons/ha), then Toplite (28.9 tons/ha), Harvestor XL (28.2 tons/ha) and the one with least yield was Control (22.1 tons/ha). Significantly higher yields were obtained with a spray interval of 7 days (35.8 tons/ha) than 14 days (20.2 tons/ha). Results show that the most effective fungicides were Indofil and Toplite and 7-day spraying interval that significantly reduced late blight incidence and severity.