OBJECTIVE MEASURMENT AND MANAGEMENT OF TURICICUM LEAF BLIGHT [Exserohilum turcicum(Pass.) Leonard & Suggs] OF MAIZE (Zea mays L.) SEVERITY USING IMAGE PROCESSING

Abstract

Turcicum is caused by the fungus (Exserohilum turcicum (Pass.) Leonard & Suggs) and appear on the leaves of maize at any stage of growth. The turcicum leaf blight injures or kills the maize leaf tissues and thereby reduces the area of green chlorophyll which manufactures/synthesise food for the plant. Traditionally, application of fungicides is carried out manually without objectively quantifying the severity of the disease caused by turcicum leaf blight leaf spot. In this research work, digital image processing techniques was used to estimate the disease severity of live-maize leaves by extracting the area feature. Total area of leaves and area of diseased region of leaves were extracted from 264 maize-leaf images captured in four rounds. First round was before spraying fungicide, second round was one week after the first round fungicide sprayed, third round was one week after the second time fungicide sprayed and forth round was a week after the third time fungicide sprayed. Control group was the one on which fungicide was not sprayed (group one). Then, the RGB images were converted to CIELAB color space and the detection of turcicum leaf blight was performed using the k-means clustering to estimate the disease severity of the leaves. MatLab based algorithms were developed to determine the total area and infected lesion area of the leaf samples. The severity levels leaves were also assessed by two experts, visually. In most samples, the two experts scored different values for the same sample leaves. The optimum volume of fungicide is obtained at group 7 and 8 which means the plot of maizes on which 70.89ml, and 74.25ml fungicide. The accuracy of the algorithm developed for estimation of disease severity using image technology was 95.6%. Thus, atomated measurement of disease severity on maize leaf gives accurate result. The result of algorithms developed shows that the possibility of measuring Turcicum leaf blight of maize leaf and estimating its optimum volume of fungicide.