Organic management of Alternaria leaf spot of cotton

Abstract

Cotton is the most important fibber in the world. It belongs to the botanical family ‘’Malvaceae”. Cotton is referred to as “king of Fibres” and is also popularly known as “white Gold”. Alternaria leaf spot of cotton is the major disease caused due to invade of Alternaria alternata. Three cow products and three botanicals viz., Cow dung, Cow urine, Milk whey, Azadiracta indica (leaf) extract, Garlic bulb extract and Calotropis gigantean (leaf) extract were incorporated to evaluate against Alternaria alternata. The treatments where used at 10%, 20% and 25% concentrations in invitro conditions during the experiments. Maximum Inhibition of mycelium was observed in Azadiracta indica (leaf) extract is 42.24% followed by Garlic bulb extract (39.77%) and Cow urine (37.37%) while minimum Inhibition of mycelium in Cow dung (25.86%) followed by Milk whey (28.61%) and Calotropis gigantean (leaf) extract 50% WP (33.35%). On the basis of colony colour, Alternaria alternate pathogen treated with different cow products and botanicals against Alternaria leaf spot of cotton was observed Greyish black colony colour in all treatments except cow urine and milk whey which shows Greyish colony colour after inoculation under in vitro condition. Under in-vivo conditions , Maximum disease reduction (%) was recorded in Azadiracta indica (leaf) extract is 32.52% followed by Garlic bulb extract is 29.27% and Cow urine is 26.84% while minimum disease reduction (%) was recorded in cow dung is 17.08% followed by Milk whey is 21.95% and Calotropis gigantean (leaf) extract is 23.58%.