Compatibility of pesticides with bacterial bio-agents effective against Xanthomonas axonopodis PV. Punicae causing blight in pomegranate

Abstract

The bacterial bio-agents viz., Bacillus subtilis-KK-9A (Bsp), Brevibacillus borstelensis-BK-6 (Bb), Brevibacillus sp-PM-2A (Bsp) and Lysinibacillus xylanilyticus- VK-6B (Lx) which were reported as effective against Xanthomonas axonopodis pv. punicae causing bacterial blight of pomegranate were further confirmed for their efficacy. The experiment was conducted to understand the compatibility of these bio-agents among and with other agro-chemicals (fungicides, insecticides, bactericides, nematicides and disinfectant) routinely using in pomegranate feild. Among eight fungicides tested, three fungicides viz., Bordeaux mixture, carbendazim and difenconazole and one dis-infectant bleaching powder were found compatible and able to recover the growth of bioagents on their poisoned medium in all the concentrations tested. The fungicides viz., chlorothalonil, copper oxychloride, hexaconozole, propiconazole, and mancozeb found incompatible with all the four bio-agents. All the four insecticides tested viz., dichlorovas, chlorpyrifos, imidachloprid and dimethoate and a nemeticide, phorate found compatible and allowed the bacterial bioagents to grow excellent (+++) on their poisoned medium at all concentrations. Whereas carbofuron found incompatible. Unfortunately there was no growth of bacterial antagonists was found in streptocyclin, K-cyclin and 2-bromo-2-nitropropane-1, 3-diol tested.