STUDIES ON THE BIOLOGICAL CONTROL OF TOMATO ROOT ROT DISEASE

Abstract

Tomato are subject to several diseases during growing, marketing and storage in Egypt, which reduce the quality and quantity of tomato fruits, particularly, damping-off and root rot diseases incited by several soil fungi. Fusarium so/ani was the most prevailing fungus followed by Rhizoctonia so/ani. The two fungi were the more pathogens exhibited severe root rots. There are a positive relationship between the percentage of infected plants and the amount of the two tested fungi inoculum. Varietal reaction of tomato against root rots showed that UC-97.3 and Peto 86 were less susceptible. Bacillus subtills was the most effective in reducing mycelial growth of the tested fungi followed by T koningii. On the other hand, addition ofT koninngii or T glaucum (2) at 2.5% before sowing with one week showed higher control of tomato root rots and increased survival plants .Where as adding antagonistic organisms filtrates at 50 mllkg. soil diminished root diseases. Plant-guard at 5 milL. gave highest effect in reduction growth of the two fungi, while Rizo-N and clean-root were less effective. On the other hand, plant-guard and clean root reduced damping-off. Clean root was the most effect in controlling tomato root rot followed by Rizo-N at 5 g/ kg. seeds. Using of antifungal plant oils for controlling tomato root rots proved that cinnamon oil at 800 ppm reduced the growth of the tested fungi. Soaking tomato seeds in cinnamon oil at 50% gave the best effect in controlling damping-off whereas garlic and eucalyptus oil reduced damping-off and increased survival plants. As for, soaking tomato seeds in plant extracts to control root rots proved that extract spearmint gave the highest effect in controlling damping-off and root rot diseases.