Cotton is an essential crop with widespread cultivation all around the world. However, cotton crops are often subject to diseases, with angular leaf spot being a common problem. This disease can lead to considerable losses in cotton yield if not managed effectively. In this article, we will discuss measures that can be taken to control angular leaf spot in cotton.
Angular leaf spot in cotton is caused by the fungus Xanthomonas campestris pv. malvacearum. This fungus affects the leaves of the cotton plant, leading to the formation of irregular angular lesions that are yellowish-green or water-soaked in appearance. These lesions eventually turn brown with yellow borders and can cause defoliation of the plant. Infected plants may also produce fewer or smaller bolls, leading to reduced yields.
As with all fungal diseases, prevention is better than cure when it comes to angular leaf spot in cotton. One crucial measure is planting disease-resistant varieties of cotton. These varieties are less susceptible to infection and can withstand the disease to a large extent. Therefore it is important to select these varieties for planting.
Another preventive measure is crop rotation. The fungus can survive in cotton debris lying on the ground, so planting cotton in the same field continuously only helps spread the disease. By rotating the crop with other crops such as legumes, non-host plants or grasses, the buildup of the fungus in the soil can be reduced, leading to a lower incidence of the disease.
Spraying of chemical fungicides can also be done, to control the disease in case of outbreaks. Copper-based fungicides, such as copper oxychloride and Bordeaux mixture, are widely used to control angular leaf spot. These fungicides suppress the disease and prevent its further spread, but may have environmental implications. They should be used in line with the instructions provided and appropriate protective measures should be taken when applying them.
Amid concerns of adverse environmental impacts, use of integrated disease management (IDM) practices to control angular leaf spot is recommended. IDM practices include combining the methods mentioned above to reduce use of chemical pesticides, while still gaining better yield.
In conclusion, angular leaf spot can cause significant losses in cotton yield. Therefore, it is important to adopt preventive measures like planting disease-resistant varieties of cotton, crop rotation and integrated disease management practices. Chemically treating cotton crops with fungicides should be the last resort in case of existing infections as it could contribute to concerns surrounding environment, human health and welfare.