Mass Production of Biocontrol Agents for Field Application and Plant Diseas Control

Abstract

Eleven different substrates viz., rice grain, sorghum grain, millet grain, cotton cake, mustard cake, wheat straw, rice straw, saw dust, sugar cane bagasse, sugarcane ash and wheat bran were used for mass production of biocontrol agents viz., Paecilomyces lilacinus, Trichoderma harzianum, Gilocladium virens and Rhizobium meliloti. Rain grain, sorghum grain, millet grain and wheat bran were found suitable substrate for mass production of P. lilacinus and R. meliloti. Good growth of Trichoderma harzianum, Gilocladium virens was observed on sorghum grain followed by millet grain, rice grain, wheat bran, wheat straw, rice straw and sugarcane bagasse. Oil cakes, sugarcane ash and saw dust were found not suitable substrates for multiplication of microbial antagonists. The inoculum multiplied and stored in plastic bags remained viable for up to 360 days at 300C. Inoculum pellets of P. lilacinus and its conidial powder stored at 50C retained the viability of fungal propagules for >120 days.

P. lilacinus inoculum multiplied on rice grain and wheat bran for up to 15, 30, 60, 90, 180 and 360 days was found effective in the control of Fusarium infection on mungbean. A 30- and 60-days old inoculum of P. lilacinus on rice grain, millet grain, sorghum grain and wheat bran showed complete control of M. phaseolina whereas 360 days old inoculum on wheat bran and millet grain showed significant reduction in M. phaseolina infection. P. lilacinus inoculum multiplied on sorghum grain, millet grain and wheat bran were found effective against R. solani infection whereas 360 days old inoculum on millet grain completely controlled R. solani infection on mungbean. T. harzianum after multiplication on rice and sorghum grain reduced the infection of Fusarium spp., whereas inoculum multiplied on sorghum grain, sugarcane bagasse and wheat bran were found effective against M. phaseolina. G. virens inoculum multiplied on sorghum grain was effective against M. phaseolina whereas rice grain and millet grain was found effective substrates against R. solani and sugarcane bagasse against Fusarium spp. R. meliloti inoculum on millet grain, rice grain and wheat bran showed significant reduction in M. phaseolina infection on mungbean roots. inoculum multiplied on rice grain and sorghum grain provided complete prevention of R. solani infection on mungbean roots. Inoculum pellets of P. lilacinus were effective in control of Fusarium spp., R. solani and M. phaseolina. A correlation between reduction in infection and the amount of antagonist inoculum used as soil amendment was observed. Use of T. harzianum showed significant reduction in infection of sunflower roots by M. phaseolina, F. oxysporum and R. solani at low production level of the pathogens with no reduction in infection at high population levels.

Soil amendment with microbial antagonists after multiplication on different substrates was found significant in reducing infection of roots by R. solnai and Fusarium spp., followed by soil drenching and seed treatment. alginate pellets containing conidia of P. lilacinuns @ 1 pellet/pot and T. harzianum @ 1 & 10 pellets/pot showed Significant in M. phaseolina infection infection on mungbean and chickpea. P.lilacinus @ 10 pellets/pot and T. harzianum @ 1 & 5 pellets/pot controlled R. solani infection on mungbean. Colonization of Fusarium on mungbean and chickpea was also significantly reduced. Alginate pelleting of mungbean seed with P. lilacinus completely controlled. R. solani infection on mungbean and also reduced Fusarium infection and colonization on mungbean and chickpea roots. Pelleting of seeds with a combination Stachybotrys atra and R. meliloti was effective against Fusarium spp., R. solani and M. phaseolina on mungbean whereas R. solani infection was completely controlled on cowpea. Use of inoculum pellets of P. lilacinus was found most effective against M. phaseolina, R. solani and Fusarium infection on mash bean followed by soil drenching and seed pelleting. Mungbean, mash bean, sunflower and chickpea seeds pelleted with P. lilacinus stored at room temperature showed a complete loss in viability of P. lilacinus conidia after 160 days storage, whereas, pelleted seeds stored at 40c showed a gradual decline in the viability of conidia with the increase in storage time. Pelleting of mungbean, mash bean and sunflower seeds with R. meliloti showed no significant variation in population of R. meliloti during 160 days storage.