In vivo evaluation of garlic (Allium sativum) extract in the control of potato late blight disease caused by phytophthora infestans

Abstract

 In vivo study was conducted to evaluate the efficacy of foliar application of garlic extract and two chemical fungicides (ridomil and z-force) in the reduction of late blight caused by Phytophthora infestans, increase of potato biomass and total tuber yield in natural field condition. The field experiment was conducted in Machambe village, Bokkos Local Government Area of Plateau State. Certified seeds were obtained from the National Root Crop Research Institute, Kuru, Plateau State, Nigeria. Potato seeds were grown in four row plots, 30-meter-long with spacing of 70cm between rows and 30cm within rows. Experiment was laid out in a Complete Randomized Block Design (CRBD) with four replications. Foliar sprays of 0.4 g/l Ridomil, Z-force and garlic extract respectively, at a 3day interval soon after first visible symptoms appeared to reduced disease incidence and resulted in higher biological and tuber yield compared to control (unsprayed plots). Ridomil and garlic extract were most effective in minimizing the disease incidence and producing better biological yields (33.95g and 31.02g) and tuber yields (15.93t/ha and 14.99t/ha) respectively. Control plot produced the least biological and tuber yield of 23.92g and 11.95t/ha respectively. There was no significant difference at P<0.05 between the tested treatments. There was significant difference in disease incidence reduction at (P<0.05) by the extract and chemical fungicides. Late blight incidence reduction effect of garlic extract was slightly higher than that of Z-force fungicide. Therefore, the evaluated plant material (garlic extract) could serve as an alternative to chemical fungicide in the control of late blight disease in potato.