The primary symptom of cotton leaf curl virus is the upward curling of leaves. Additionally, leaf veins can thicken and darken, and outgrowths (enactions) may form on the undersides of leaves, typically in the shape of leaves. Flowers may stay closed and then drop along with the bolls. If plants are infected early in the season, their growth will be stunted and yield will be reduced significantly.
Symptoms are caused by the cotton leaf curl virus, which is primarily transmitted through whiteflies. The spread of the disease is in part determined by prevailing winds, which will indicate how far the whiteflies can travel. Whiteflies are most problematic in the mid- to late season. The disease is also associated with shelters, such as trees. Since the disease is not seed-borne, the virus persists in the landscape via alternative hosts (such as tobacco and tomato) and weeds. Some additional factors that can favor development of the disease are recent rainfall, infected transplants, and the presence of weeds. The virus is also most likely to spread under a temperature range of 25-30ºC. In nurseries, cotton plants are most prone to infection during the seedling and vegetative stages.
Whitefly populations can generally be controlled by natural enemies (e.g. lacewings, bigeyed bugs, minute pirate bugs), so be careful not to kill them with rampant spraying of chemical pesticides. Neem oil or petroleum-based oils can be used and should thoroughly cover the plants, particularly the undersides of leaves. Recent research has also indicated the potential of using biocontrol agents such as beneficial isolated bacterial strains (Bacillus, Pseudomonas and Burkholderia) as a means of reducing the incidence of the virus.
Always consider an integrated approach with preventive measures together with biological treatments if available. There are no known methods for preventing or reducing cotton leaf curl virus. Chemical control in the form of insecticides can be used to control the whitefly population, such as imadacloprid or dinotefuran. Insecticides should be approached with caution however, because excessive usage of insecticides has caused many whitefly species to become resistant to them. To reduce the likelihood of this occurring, be sure to rotate between insecticides.