Comparative efficacy of Trichoderma harzianum application methods for controlling Rhizoctonia solani in peas (Pisum sativum L.)

ABSTRACT The use of Trichoderma has been widely used to control R. solani but however there is need to evaluate the different mechanisms used to administer the Biological Control Agent into the plant environment. A greenhouse experiment to compare the efficacy of three T. harzianum application methods i.e. seed bio-priming, seed coating and soil treatment to control R. solani in peas was carried at Kutsaga Research Station. The main objective of this study was to evaluate the efficacy of T. harzianum application methods for controlling root rot and damping off caused by R. solani in peas. Seeds were sown in artificially infested soil in 22.5 cm wide pots. Data on pre emergence, post emergence, root rot severity and T. harzianum CFU concentration in the root rhizosphere were recorded and analysed using GenStat. There were significant differences between all application methods on all measured parameters. T. harzianum seed bio-priming have significantly recorded the lowest pre and post emergence damping off disease incidence of 8 % and 11 % respectively. T. harzianum soil treatment have significantly suppressed root rot severity and recorded the lowest severity score of 1.5. In determining the T. harzianum CFU concentration in the root rhizosphere T. harzianum soil treatment significantly recorded the highest population increase rate at 6 WAS. Seed biopriming have greatly reduced both pre emergence and post emergence damping off and also resulted in low disease severity cause by R. solani. T. harzianum applied as soil treatment have greatly suppressed root rot severity and recorded a significant increase in CFU in the root rhizosphere.