Studies on Forecasting of Incidence of Leaf Mold in Tomato and Fungicide-spray Scheduling

Abstract

Tomato leaves were inoculated with 1x104conidia{middle dot}mL-1 and placed in a dew chamber for 0 to 18hrs at 10 to 25{degrees}C. Eighteen days after inoculation, leaf mold incidence appeared in 9hr treatment of leaf wet duration and the proper temperature was 15 to 20{degrees}C. In 10 and 25{degrees}C treatments, the incidence rate was 0% and 4.2%, respectively. The most important factors regard to leaf mold incidence were leaf wet duration and temperature. Considering the proper tomato growth temperature is 15-25{degrees}C, control by leaf wet duration is easier than control by temperature to prevent leaf mold incidence. After leaf mold inoculation, incidence appeared at 20 days and the latency period was estimated as 14-15 days. The leaf mold incidence rate was the highest at 15{degrees}C and 20{degrees}C. When trihumin (triflumizole 30%) was applied at 12 hr of leaf wet duration, the control effect was the highest at 90% up to 168 hr but after 240 hr, it dropped to 60%. When Demani B (polyoxin B 50%) was applied at 12 hour of leaf wet duration, the control effect was the highest at 91% up to 144hr but after 240hr, it dropped to 58%, similar to trihumin application treatment. When belqute (Iminoctadine tris 40%) was applied at 12 hours of leaf wet duration, the control effect was the highest at 93% up to 144 hr but after 240 hr, it dropped to 65%.