Eggplant Integrated Pest Management AN ECOLOGICAL GUIDE

___________________________________________________________________________________________Disease EcologyCreation of a disease triangle in a workshop on management of soil-borne diseases, Hai Phong,Vietnam (1999).Participants of this workshop, mainly IPM trainers, discussed about disease development, with theobjective to develop studies (Participatory Action Research) with IPM farmers on diseasemanagement. One of the diseases selected to prepare a disease triangle was bacterial wilt in tomato.The following management methods for bacterial wilt resulted from the discussions:PATHOGEN• Using compost (to improve soil structure, increasesoil nutrients, reduce soil-borne pathogens,strengthening activities of beneficial organisms)(X)• Practicing proper field sanitation (X)• Collecting diseased plants (X)• Choosing disease-free soil• Using clean water for irrigation• Being careful about pruning and sprout removal• Using non-diseased seedlings• Practice crop rotation when soil is infected (X)HOST PLANT• Selecting healthy seedlings• Applying compost (X)• Applying nitrogen properly (X)• Practicing crop rotation (X)• Selecting resistant variety (X)• Controlling weedsENVIRONMENT• Growing tomato in main season and in late season (X)• Avoiding growing crop in sandy loam because fields oftenflooded (X)• Constructing high beds for good drainage (X)• Making soil crumbly, avoiding fields from becoming toodry• Using proper spacing, i.e. do not grow plants too close• Staking• Pruning• Applying compost (X)(X) = done by all Vietnamese farmers (according to workshop participants).(from: FAO Workshop on PAR on management of soil-borne diseases, 1999)7.6 A disease or not a disease...? How to find out!Very often, it is difficult to tell if a brown or black spoton the leaf or a piece of dead leaf is actually adisease or just a little insect damage or mechanicaldamage. Sometimes the symptoms of diseases arenot very clear, or a different environment or climatemakes a symptom look slightly different from the“theoretical” symptoms.It is important to find out because if a spot or adiscoloration is actually a disease, you may still beable to do something to prevent it from spreadinginto the rest of the field. This can be uprooting thediseased plants. For some diseases you may haveto spray a fungicide to stop the spread. It is important to train yourself in recognizing early symptoms of adisease. If you can see the first symptoms of a disease early, there may still be time to prevent it fromreaching a damaging level of infestation.122Eggplant Ecological Guide