Late blight of potato, caused by Phytophthora infestans, is a devastating disease that affects potato crops worldwide, resulting in significant yield losses. The disease can also infect other crops in the Solanaceae family, such as tomato and eggplant. Managing the disease involves adopting an integrated approach, which includes various control measures.
Cultural Control Methods
Crop rotation is an essential cultural control measure that involves growing crops that are not susceptible to late blight in the same field for several years before planting potato. This can help reduce the pathogen’s population in the soil as well as decrease the risk of infection at planting time. Farmers should also adopt good hygiene practices, such as destroying cull piles and infected plant debris, as these can act as sources of inoculum for late blight spores.
Chemical Control Methods
Chemical control options for late blight include application of fungicides, which work by preventing the pathogen from infecting the potato plant. Fungicides can be applied on a regular schedule based on weather conditions or following an infection warning provided by disease forecasting systems. Fungicides containing active ingredients such as chlorothalonil, mancozeb, or copper-based compounds are commonly used to control the disease.
Biological Control
Biopesticides like Trichoderma spp., Bacillus subtilis and Pseudomonas fluorescens can be used to control the spread of Phytophthora infestans in soil. These biocontrol agents produce metabolites that reduce the growth of the pathogen in the rhizosphere. However, this approach is generally effective when used with other control measures.
Genetic Control
In recent years, genetic control methods for late blight have been developed. These methods include the use of genetically modified potato plants that express resistance genes to the pathogen, such as RB and RB-like genes. However, this approach is still in the early stages of development and has not been widely adopted.
In conclusion, controlling late blight of potato is a complex task and requires a combination of different measures. Farmers should adopt cultural practices, use fungicides when necessary, and consider the use of biocontrol agents to limit infection. Additionally, the development of genetically resistant potato varieties has the potential to offer a long-term solution to the disease.