Effect of some bio-products on the growth of Helminthosporium maydis, causal agent of Southern Corn Leaf Blight by dual culture technique under in-vitro condition

Abstract

Maize belongs to the family Poaceae, is the third most important cereal crop under irrigated and rainfed agricultural system in semi-arid and arid tropics and also known as queen of cereals. The yield of this crop is challenged by a number of biotic stresses among which maydis leaf blight disease caused by Helminthosporium maydis / Bipolaris maydis is very much important. Proper management of this disease should be followed for minimizing the loss due to a disease attack. Cultural, chemical and biological control measures are important ways of disease management. Control of plant diseases by using biocontrol agents and natural / plant products is an eco-friendly & sustainable approach. Considering the hazardous effects of fungicides and chemicals, in this experiment for the purpose of management of MLB of maize by using eco-friendly ways three bio-control agents and three natural products were tested against H. maydis under in-vitro condition. Two plant extracts Allium Sativum (garlic), Azadirachta indica (neem), three bioagents Trichoderma viride, Trichoderma harzianum, Pseudomonas fluorescence and one natural product cow urine were tested against the growth of Helminthosporium maydis under in-vitro condition. Among the six treatments minimum radial growth (1.13cm) & maximum growth inhibition (82.8%) of Bipolaris maydis was found in case of application of Trichoderma harzianum followed by Trichoderma viride (radial growth – 1.30cm & growth inhibition 80.21%) with no significant difference among them. The growth inhibition of 35.61% was recorded in case of Pseudomonas fluorescens respectively. Better result was obtained when three bio-control agents were applied but among the natural products better result (radial growth 4.47cm & growth inhibition 31.96%) was obtained with application of garlic bulb extract (10%) followed by application of neem extract (25.11). Six botanicals were evaluated in-vitro against Helminthosporium maydis. The result revealed that, bulb extract of garlic (Allium sativum) at 10 per cent concentration completely inhibited mycelial growth of the fungus. Among the six treatments minimum radial growth (1.13cm) & maximum growth inhibition (82.8%) of Bipolaris maydis was found in case of application of Trichoderma harzianum followed by application of Trichoderma viride (radial growth – 1.30 cm & growth inhibition 80.21%) with no significant difference among them. Better result was obtained when three bio-control agents were applied but among the natural products better result (radial growth 4.47cm & growth inhibition 31.96%) was obtained when garlic bulb extract (10%) was applied.