EFFECT OF AJOENE, A CONSTITUENT OF GARLIC (ALLIUM-SATIVUM) ON POWDERY MILDEW (ERYSIPHE-PISI) OF PEA (PISUM-SATIVUM)

The germination of conidia of Erysiphe pisi on and in water was seen. There was no significant difference in germination percentage. The effect of ajoene, a compound derived from garlic (Allium sativum L.), along with two commercially used fungicides, viz., Sulfex and Bavistin, on germination, appressorium and multiple germ tube formation in E. pisi conidia on detached pea leaves, and also on disease intensity in a growth chamber was studied. Among several doses of ajoene (2, 12, 16, 20 and 25 mg/l) complete inhibition of conidial germination was observed at 25 mg/l. Ajoene spray at 1000 mg/l gave good control of powdery mildew in a growth chamber which was almost at par with Sulfex and Bavistin. The possibility of using ajoene to control pea powdery mildew (E, pisi) under field conditions has been discussed.