Eggplant Integrated Pest Management AN ECOLOGICAL GUIDE

__________________________________________________________________________________Major Diseases of Eggplantsusceptible to these fungi. Seeds from infected fruits are another source of infection. Transplants alsoserve as a source of inoculum.Role of environmental factorsDisease incidence increases as humidity and temperature rise.Most anthracnose fungi grow at temperatures of 13 to 35 o C with optimum growth at around 27 o C.Anthracnose needs a lot of water to develop (a humidity is 93% or above). That is why rainfall (andoverhead irrigation!) favors disease development.Importance - plant compensation - physiological impactAnthracnose can reduce a bountiful harvest into rotted fruit in a few days in warm, moist weather.If fruits drop off the plant early in the season, the plant may be able to produce new ones. However, thisis unlikely as anthracnose usually affects ripe fruits.Natural enemies/antagonistsUnknown.Management and control practicesPrevention activities:• A 3-year crop rotation schedule with other solanaceous crops is advised to lower field incidence ofanthracnose. See section 3.17.• No anthracnose-resistant eggplant varieties have been reported.• Use disease-free seeds (check “certified” seeds, or use a coating before sowing – see section 3.6)and/or use healthy transplants.• Sanitation: remove all infested plant debris from the field and drop it onto a compost pile outside themain field or feed it to farm animals.• Plant in well-drained fields to avoid excess soil moisture as fruit ripens.• Prefer furrow to overhead irrigation. If overhead irrigation is used, apply it during the early part of theday so that plants dry before sundown.• Harvest and use fruit before it fully ripens.Sanitation: remove plant parts….to where?☺It was noted that some farmers practice field sanitation very properly by removing all cropresidues from the field after the final harvest. However, after collecting all plant debris, they threw it to the sides of the field. From there,spores of many fungi can easily infect the next crop or a neighboring crop.☺ Take crop debris away from the main field for decomposing or as food for farm animals.Once disease symptoms are found:• In areas where anthracnose is a frequent and serious problem, the use of fungicides can beconsidered. Many fungicides need to be applied preventively, that means before disease symptomsare found. It is however dangerous to spray during the fruiting stage as residues of the pesticide mayremain on the harvested fruits! Note that some natural enemies of insect pests may be killed byfungicide sprays as well!Points to remember about anthracnose fruit rot:1. Anthracnose-causing fungi can affect both fruits and leaves. Fruit infection is most severe as itresults in unmarketable fruits.2. Anthracnose-fungi survive in infested plant debris in the soil and on seeds of infected fruits.3. Use of clean seed and healthy transplants, good sanitation practices, and using furrow ratherthan overhead irrigation are ways to prevent anthracnose infection.145Eggplant Ecological Guide