Effect of Pyrolysis Products on Management of Ascochyta Blight (Ascochyta Rabiei) and Performance of Chickpea (Cicer Arietinum L.)

Abstract

Chickpea is a drought-tolerant and nutritious legume with great potential to mitigate the impact of climate change on food and nutritional security. Its production is however limited by several fungal infections key among them is Ascochyta blight (AB) caused by Ascochyta rabiei. Efforts to manage AB have seen farmers resort to frequent use of synthetic fungicides which have negative impacts to human health and the environment. The objectives of this study were (i) to determine the antifungal effects of wood vinegar from selected feedstocks on Ascochyta rabiei in vitro. (ii) to determine the efficacy of biochar and wood vinegar on Ascochyta blight disease incidence and severity (iii) to determine the effects of biochar and wood vinegar on the performance of chickpea. Experiments were conducted in the laboratory, greenhouse and field. The laboratory experiment was conducted at Egerton University Biotechnology Laboratory to evaluate the antifungal activity of wood vinegar from maize cob, acacia trimmings, Prosopis juliflora and bean wastes on Ascochyta rabiei in vitro on potato dextrose agar (PDA) arranged in a completely randomized design (CRD). Greenhouse experiment was conducted in potted plants at Agronomy Research Field 7, Egerton University, and the field experiment at Agriculture Training Centre (ATC) Koibatek, Baringo County. The greenhouse and field experiments were arranged in a randomized complete block design (RCBD) and replicated three times. The potted plants were inoculated with A. rabiei at a spore concentration of 5x105. Data collection from the in vitro experiment included mycelia growth inhibition. For greenhouse and field experiments, data was collected on crop emergence, plant height, days to 50% flowering, biomass, number of pods, yield, disease incidence and severity. Data was analysed using SAS version 9.4 using PROC GLM procedures. The laboratory experiment results showed that wood vinegar has significant antifungal effects against Ascochyta rabiei. Wood vinegar from maize cobs showed the highest inhibition at all concentrations tested with highest concentration of phenols at 4.56 mg/ml and low pH of 3.90. The results further revealed that AUDPC and PDI were less severe at 19.70% and 23.33% when biochar and wood vinegar from maize cob were applied in soil and foliar respectively. Wood vinegar and biochar from maize cobs increased the yield of chickpea at 3.35 t/ha This study demonstrated that pyrolysis products can be used to reduce Ascochyta blight incidence and severity and increase the performance of chickpea