Eggplant Integrated Pest Management AN ECOLOGICAL GUIDE

__________________________________________________________________________________Major Diseases of Eggplant8 MAJOR DISEASES OF EGGPLANTSUMMARYEggplant can be affected by many pathogens. Major diseases of eggplant in Asia are earlyblight, root diseases and wilt.It seems obvious, but in practice it is often hard to properly diagnose plant diseases. The rightidentification of a disease, an understanding of the disease ecology, including knowledge ofthe factors influencing the disease (disease triangle), are essential elements of successfuldisease management. See chapter 7.Some general disease management practices are given here. Specific practices are listedunder individual disease sections.• Use of disease-resistant varieties. Setting up variety trials to test how particular varietiesperform locally is recommended.• Increasing soil organic matter. This can increase soil micro-organism activity, which lowerspopulation densities of pathogenic, soil-borne fungi. In addition, it increases nutrientavailability, which results in better plant growth.• Clean planting material. This includes use of clean seed (see section 3.6) and healthy,disease-free transplants.• Proper fertilizer use. Using too much may result in salt damage to roots, opening the wayfor secondary infections. Balancing watering and fertilizer is also important. The succulentgrowth of plants given too much water and nitrogen encourages certain pathogens. On theother hand, stressed plants, especially those low in potassium and calcium, are morevulnerable to diseases.• Water management. The most important practice is providing drainage to keep soil aroundroots from becoming waterlogged to prevent rotting. It is also important that foliage staydry. Infectious material or inoculum of water-borne pathogens spreads from infected tohealthy leaves by water droplets, and fungal pathogens need water to germinate and enterthe leaf (see section 3.14).• Sanitation. Removing diseased plants (or parts) helps prevent the spread of pathogens tohealthy plants. Crop left-overs can be used to make compost. Sanitation also includesweed control and, in some cases, insect control because many pathogens persist in weedhosts or are spread by insects.• Crop rotation. Rotation to an entirely different plant family is most effective againstdiseases that attack only one crop. However, some pathogens, such as those causingwilts and root rots, attack many families and in this case rotation is unlikely to reducedisease.• Use of biocontrol agents. Good results have been obtained with use of Trichoderma sp. forcontrol of soil-borne diseases, including damping-off and root rots. Several other biocontrolproducts may become available in Asia in the future.130Eggplant Ecological Guide