Evaluation of fungicides sprays frequency for the management of chickpea Ascochyta blight (Ascochyta rabiei (Pass.) Lab.) in Alemtena, East Showa, Ethiopia

Abstract

Chickpea (Cicer arietinum L.) is one of the most important grain legume crops in Ethiopia which widely grown in marginal soils and usually as rotational crops in highland and semi-highland regions of the country. Despite the large area under chickpea cultivation, total production and productivity is quite low. Ascochyta blight is one of the most important diseases of chickpea in Ethiopia that affects the quantity and quality of chickpea yield. Foliar application of fungicides with different spray frequencies are commonly recommended for Ascochyta blight management. Therefore, an experiment was conducted in Alemtena, East Showa, Ethiopia during the main cropping season of 2015 to evaluate three fungicides (Mancozeb, Mancolaxyl and Othello Top) sprays frequencies for the management of chickpea Ascochyta blight (Ascochyta rabiei (Pass.) Lab.) on growth parameters, yield and yield components and yield losses of chickpea cultivar, Natoli under field conditions. The experiment was randomized complete block design in factorial arrangement with three replications. It consisted of three levels of spray frequencies (spray every one week, spray every two weeks and spray every three weeks) of three fungicides and control (untreated) treatments. The analysis of variance showed significant differences among the treatments except for days to maturity. There was a significant difference in Ascochyta blight disease incidence, severity, and infected pods per plant, infected seeds and Area under Disease Progressive Curve (AUDPC) among treatments. The comparison of means showed that application of fungicides was a suitable strategy for reduction of Ascochyta blight incidence, severity and AUDPC values as well as the maximizing seeds per pod, pods per plant, plant height, hundred seed weight and seed yield. Seed yield on sprayed plots, ranged from 1793-2261.4 kg ha^-1 with mean values of 2061.3 kg ha^-1 while, the seed yields measured from unsprayed (control) plots were smaller than sprayed plots (1046.7 kg ha^-1). Disease severities and AUDPC rates had negative correlations with seed yield and hundred seed weight in comparison to their correlations with yield. Optimum net benefits of Ethiopian Birr, 50098.5 ha^-1 and 47922.2 ha^-1 were obtained from Mancozeb and Othello Top fungicides sprayed every three weeks, respectively and recorded highly effective in decreasing Ascochyta blight disease symptoms in chickpea cultivar Natoli and increased yield. Therefore, Mancozeb and Othello Top fungicides sprayed every three weeks are economically beneficial compared to the other treatments. Further, the effective and feasible integrated management options need to be developed on chickpea Ascochyta blight disease in the country.

Keywords: Chickpea, Ascochyta blight, Ascochyta rabiei, Fungicides, Spray frequency.