The Potential and Application Frequency of Yeast from Tomato and Cogon Grass Leaves to Suppress Powdery Mildew Disease in Tomato

Abstract

Powdery mildew (Oidium sp.) is important disease in the greenhouse tomato production. One of environmentally-friendly control method of the disease is biological control. Yeast from phyloplane of weeds such as cogon grass are potential as biocontrol agents. This study evaluated the potential of yeast isolated from the leaves of cogon grass and wild tomato to suppress powdery mildew of tomato. The samples were obtained from several areas in Sumedang and Bandung, West Java. The yeast isolates were selected on their abilities in controlling powdery mildew in tomato seedlings. The selected isolates were used for further experiment examining the effects of frequency of yeast application on the disease control. This experiment was arranged in Randomized Complete Block Design with 12 treatments and three replications. The treatments were three yeast isolates, applied once before pathogen inoculation, applied regularly every week or two weeks, the check and fungicide treatment. The results showed that among 13 yeast isolates obtained there were three isolates that suppressed
the development of powdery mildew disease by 61.0%- 68.6%. In further experiment, relatively highest disease reduction (58,6%) was showed in the application of yeast isolate from wild tomato leaves (TB1 isolate) every week.
Keywords : biological control, phyloplane, Oidium sp., wild tomato