Eggplant Integrated Pest Management AN ECOLOGICAL GUIDE

_____________________________________________________________________Ecology of insect pests and natural enemiesEffects of pesticides on natural enemies: a study example1. Prepare hand sprayers with the pesticide to be tested.2. Select a few plants in the field. Label plants with name of treatment and spray them with thepesticide. Let leaves dry on the plant.3. Pick one or several leaves from each labeled plant and place these in jars (use gloves!).4. Collect predators, e.g. spiders or ladybeetles from the field (use a small brush).5. Place predators in the jars, close the lid and place a piece of tissue paper between the lid and thejar to avoid condensation inside.6. Check condition of predators after 8 and 24 hours.Instead of leaves, a piece of cloth can be sprayed with pesticides. Rest of study as above.Note: When handling pesticides wear protective clothing and wash with plenty of soap and waterafterwards.4. If an insecticide is needed, try to use a selective material in a selective manner or very localized, oninfested plants only (spot application).5. When the borders of the field are covered with weeds, especially when they are flowering weeds,these borders can provide a shelter for natural enemies. Mixed plantings can have a similar effect.Adult natural enemies (e.g. hoverflies) may also be attracted to flowers for feeding on the nectarinside the flowers. Many adult parasitoids live longer, and are therefore more effective, when thereare sufficient flowers to feed on. Such practices are easily incorporated into home gardens and smallscalecommercial plantings, but are more difficult to accommodate in large-scale crop production.There may also be some conflict with pest control for the large producer because of the difficulty oftargeting the pest species and the use of refuges by the pest insects as well as natural enemies.6. Many adult parasitoids and predators also benefit from the protection provided by refuges such ashedgerows and cover crops. Other shelters may be provided for natural enemies to survive. Anexample is given in the box below.Manipulation of Natural Enemies in rice straw bundlesSome of the predators present in rice fields are also present in vegetables. Spiders and otherpredators seek refuge in rice straw bundles at the time of rice harvest. If these straw bundles or tentsare placed in rice fields when the crop is harvested and natural enemies are allowed to colonizethem, the bundles may be moved to vegetable plots where predators could colonize vegetablesmore quickly. Thus, conservation/augmentation of natural enemies through manipulation of strawbundles could be useful in reducing the impact of vegetable insect pests.Related exercises from CABI Bioscience/FAO Vegetable IPM Exercise Manual:4.9. and 4.10. Importance of flowers as food source to adult parasites.57Eggplant Ecological Guide