BlOLOGlCAL CONTROL FOR PHYTOPHTHORA FOOT ROOT ROT OF BLACK PEPPER, PIPER NIGRUM, IN INDIA
Indian Institute of Spices Research, Calicut-673 012, Kerala, India
Background and objectives
Phytophthora foot and root rot of black pepper, caused by Phytophthora capsici, is a major production constraint in all black pepper-growing countries. Absence of a high degree of host resistance, susceptibility of all parts of the plant to P. capsici and prolonged climatic conditions highly conducive for disease development, render disease management an onerous task. As part of an integrated disease management strategy, biocontrol programmes were found most promising. Black pepper being a high value crop, the biocontrol options are more attractive for producing organic spice. Trichoderma harzianum, Gliocladium virens, Verticillium chlamydosporium, V. tenerum and VAM (Glomus fasiculatum), isolated from rhizosphere/roots of black pepper, were found to be highly suppressive to P. capsici. Several fluorescent pseudomonad isolates from roots were equally inhibitory to P. capsici. Of these, T. harzianum or G. virens were mass multiplied on coffee cherry pulp or sorghum meal and G. fasiculatum on live roots of sorghum. The efficacy of this biocontrol inoculum was tested on black pepper at three different stages.
Nursery: yo ensure disease-free rooted cuttings, solarized nursery mixture was fortified with biocontrol inoculum, viz. T. harzianum or G. virens and G. fasiculatum, (VAM). G. fasiculatum performed a dual role of suppressing root rot caused by P.capsici, and also the two plant parasitic nematodes Radopholus similis and Meloidogyne incognita fit well into a holistic approach of disease management.
Pre-plant application: the biocontrol inoculum was applied to the planting pit at 50 g/pit (10-14x106) at the time of planting in the main field. This ensured better field establishment and robust growth of the vines.
Field application: immediately after the onset of the first few showers of the South-West monsoon (May-July), the biocontrol inoculum, 50 g/vine (10-14x106) mixed with farm yard manure (FYM) or neem kernel cake (1 kg/vine) was applied to the base of the vine and earthed up. The soil being acidic (pH 5.5-6.5), with a high organic matter and good soil moisture, the multiplication and stability of the biocontrol inoculum was found to be good.
These programmes, which were implemented in about 2000 ha in demonstration plots in black pepper plantations, showed a gradual, but steady disease suppression and consequent increase in the health of the vine as evidenced by the decrease in foliar yellowing and death of the vines. The present technology holds much promise as it is both eco-friendly and environmentally sound. The farming community has shown keen interest in this innovative technology.
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