PJB-2004-99
EFFICIENCY OF DIFFERENT NEEM (AZADIRACHTA INDICA A.JUSS) PRODUCTS AGAINST VARIOUS LIFE STAGES OF PHYTOPHTHORA INFESTANS (MONT.) DE BARY
A. RASHID, I. AHMAD, S. IRAM, J. I. MIRZA AND C. A. RAUF*
Abstract
Efficacy of different neem (Azadirachta indica A.Juss) products was investigated against Phytophthora infestans using two isolates viz., NR-971 and BN-971 differing in aggressiveness. NR-971 was virulent against 0,1,3,4,7,10,11 resistant genes while BN-971 showed virulence against 0,1,2,3,4,7 resistant genes. Three products from neem viz., neem leaf diffusate, neem leaf powder and neem seed cake were evaluated for their effect on mycelial growth, sporangial production and sporangial germination of the 2 isolates. Neem leaf diffusate and neem leaf powder completely inhibited the mycelial growth of both isolates at 2.0% v/v and 80% w/v concentration, respectively while neem seed cake showed 100% mycelial growth inhibition in NR-971 isolate at 1.0% and that of BN-971 isolate at 0.8% w/v concentration. Neem leaf diffusate completely inhibited sporangial production of NR-971 isolate at 1.0% and that of BN-971 isolate at 0.4% w/v concentration. Both neem leaf powder and neem seed cake completely inhibited sporangial production sporangial germination of NR-971 and BN-971 isolate at 0.6% and 0.4% w/v concentrations, respectively. The more virulent isolate NR-971 was found more sensitive to neem products than less virulent isolate BN-971.
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