International Journal of Plant Protection

P. K. Meena ¹, R. S. Ratnoo ²

Affiliations
1 Department of Plant Pathology, Rajasthan College of Agriculture, Maharana Pratap University of Agriculture and Technology, Udaipur Rajasthan
2 Department of Plant Pathology, Rajasthan College of Agriculture, Maharana Pratap University of Agriculture and Technology, Udaipur Rajasthan, IN

Abstract

The principal part affected is the leaf on which small, dull to dark brown, circular or irregularly shaped spots appear, the spots varying in diameter from 0.5 to 10 mm. When these spots mature they have dry, grey centres which may crack and even drop. The spots may coalesce and occupy large area of the leaf. Fungal pathogens were isolated, purified and identified asAlternaria alternata, Alternaria macrospora and Alternaria gossypina and pathogencity was confirmed on Bt and non Bt cotton in potted plants. In potted plants, minimum disease severity were obtained in Mancozeb and Hexaconazole followed by Copper oxychloride and Tilt. All fungicides as foliar sprays were able to reduce disease severity over untreated control at 0.2% followed by 0.1% concentration. Mancozeb and Hexaconazole were found most effective in management of Alternaria leaf spot of cotton.

Keywords

Fungicides, Plant Extract, Alternaria Alternata, A. Macrospora, A. Gossypina

Full Text

     

P. K. Meena ¹, R. S. Ratnoo ²

Affiliations
1 Department of Plant Pathology, Rajasthan College of Agriculture, Maharana Pratap University of Agriculture and Technology,Udaipur Rajasthan, IN
2 Department of Plant Pathology, Rajasthan College of Agriculture, Maharana Pratap University of Agriculture and Technology,Udaipur Rajasthan

Abstract

In vitro physiological studies revealed that fungus grew well on PDA and malt extract media. Maximum mycelial growth was recorded on Potato dextrose agar medium at 25±2°C temperature and pH 7.0 for all the three Alternaria spp. The severe symptoms were produced by Alternaria alternata Alternaria macrospora and Alternaria gossypina. Thus, it was confirmed that the maximum toxin was produced by Alternaria alternata as compared to Alternaria macrospora and Alternaria gossypina. Non-Bt cotton plants were more susceptible as compared to Bt cotton plants.

Keywords

Sporulation, Media, Toxin,alternaria Spp., Leaf Spot, Bt Cotton, Non-bt Cotton

Full Text