Efficacy of Trichoderma hamatum in the Management of Rice blast (Magnaporthe oryzae)

Abstract

Rice is a crop of economic importance worldwide and over 3.5 billion people depend on it as a staple food source. Rice is considered the third most important cereal crop in the world after maize and wheat, which is grown as semi-subsistence crop mainly by smallholder farmers. In recent years, rice demand has been on the increase while its production is on the decrease due to biotic and abiotic stresses. Amongst the biotic factors, rice blast caused by Magnaporthe oryzae remains the major limiting factor affecting smallholder rice farmers. The disease is capable of causing 60-100% yield losses in rice production. Similarly, smallholder rice farmers are faced with abiotic challenges such as nutrients deficiency which can cause up to 16-33% yield loss per hectare in rice production. In address of these challenges, synthetic fungicides and fertilizers have been used prophylactically to manage the disease and to enhance nutrients efficiency; which are not environmentally friendly. Environmental benign approaches for pest, nutrients enhancement and diseases management is necessary. Thus, the use of biopesticide may offer sustainable strategies in the management of diseases and nutrients enhancement in rice production. Therefore, this study was carried out to assess the efficacy of T. hamatum against rice blast and its capacity to enhance rice yield. Hence, the biopesticide was delivered as seeds-priming, roots dipping and foliar spray in the greenhouse at Jomo Kenyatta University of Agriculture and Technology; which does not impose health danger to the users, consumers and the environment. Each treatment consisted of three replicates and each replicate had nine rice plants. The study was conducted using the complete randomized design under two separate trials. Trial one commenced November, 2023 to March, 2024 and trial two started March, 2024 to June, 2024. Data was collected on disease incidence and severity, rice tiller number, rice height, grains yield and dry root and shoot weights. The disease was scored on a scale of 0-10. The data was analyzed using one-way analysis of variance in GenStat, 14th edition. The treatment means were separated using Tukeys Studentized Test at 5% significance level. The results of this study have demonstrated that the modes of application of T. hamatum was significant in the management of rice blast (p<0.001). The results have indicated that both leaf and panicle blast severity was reduced in the foliar sprayed rice, compared to the seeds primed and roots dipped rice plants (p<0.001). The difference in blast severity could have emanated from the fact that T. hamatum is well colonized in the leaves than other parts of the plant. Hence, offering better control over the seeds primed and roots dipped rice plants. This study concludes that there is potential in the use of T. hamatum in the management of rice blast. Field trials are recommended to gain further insights into the potential of T. hamatum in rice blast control and nutrients enhancement.