Mitigating Phytophthora foot rot and slow decline diseases of black pepper through the deployment of bacterial antagonists

Abstract

Field trial was conducted at ICAR-IISR Experimental Farm, Peruvannamuzhi, Kozhikode district, Kerala, during 2008-2013 for managing foot rot and slow decline diseases of black pepper using IPM modules. Planting material of black pepper was produced by raising two node runner cuttings treated with chemicals/bioagents. A plot having non-living standards in 3 x 2 m runner was selected. Pits of 50 cm3 were made and buffered with lime and cow dung. Planting was done with three month old rooted plants where roots were primed with bacterium/chemical. The experiment was in RCBD with eight treatments viz., Pseudomonas aeruginosa (Bp 35) + Phorate, P. putida (Bp 25) + Phorate, P. fluorescence (IISR 6) (later identified as P.aeruginosa) + Phorate, Bacillus megaterium (Bp 17) + Metalaxyl Mz, Curtobacterium luteum (TC10) + Metalaxyl Mz, P. aeruginosa (IISR 853) + Metalaxyl Mz and Phorate + Metalaxyl Mz (chemical check) and an absolute control with no treatments. The treatments were imposed at planting in May and subsequent applications in September and thereafter every year. During the initial two years, plants were maintained weed free by plastic mulching. Shades and irrigation were provided during summer in the first two years and thereafter only mulching and irrigation were continued. All the plants were sprayed with ZnSO4 (0.25%), DAP (0.5%) and MgSO4 (0.25%) during May and September from second year onwards. For controlling ‘Pollu’ beetle (Longitarsus nigripennis) and anthracnose (Colletotrichum gloeosporioides), quinalphos (0.075%) + Bordeaux mixture (1%) was sprayed twice in September and November. Soil biological properties and pathogen population were monitored regularly. No foot rot incidence due to Phytophthora spp. could be noticed in any of the treatments till the end of the experimental period. However, nematode infection, manifested as yellowing of the vines, as well as nematode population showed a gradual increase. Among the treatments, C. luteum (TC 10) with Metalaxyl Mz showed significant reduction in nematode population with better growth and yield.