Eggplant Integrated Pest Management AN ECOLOGICAL GUIDE

_____________________________________________________________________Ecology of insect pests and natural enemies4.11.11 Pesticide associated problems on insects and natural enemiesDespite the advantages of conventional insecticides, there are numerous problems associated with theiruse. These include:1. The resurgence of pest populations after elimination of the natural enemiesA well-known phenomenon is that when natural enemies are killed by pesticide applications, pest insects(which often have a high reproduction rate) can increase their numbers very quickly. This eventuallyresults in yield and quality loss of the crop. Even pest insects that, under no or low pesticide applicationscause no problem (populations are kept low by natural enemies) can cause outbreaks and yield losswhen natural enemies are eliminated, especially insects or mites that have developed resistance againstpesticides. An example is red spider mite, which has many natural enemies but can cause severeproblems in heavily sprayed fields.2. Development of insecticide-resistant populationsThe development of resistance is one of the more serious problems in pest management. Resistancemeans an insect can tolerate a pesticide without being killed. This is more likely to occur in a pest than ina natural enemy. Many insect pest species now have resistance to some or several types of insecticides,and few chemical control options exist for these pests.The number one resistant insect is the aphid, Myzus persicae (Homoptera: Aphidae). This aphid isresistant to more insecticides than any other insect. The numbers two and three notoriously resistant arethe Colorado potato beetle, Leptinotarsa decemlineata, and the diamondback moth, Plutella xylostella(ref. www23). In some areas, the diamondback moth has even become resistant to biological controlagents like Bt (Bacillus thuringiensis).3. Negative impacts on non-target organisms within and outside the crop systemNumerous cases exist of negative impact of pesticides on humans and livestock. Many farmersparticipating in FFSs have experience with pesticide poisoning, or side-effects on health from pesticides.Natural enemies are generally more adversely affected by chemical insecticides than the target pest.Because predators and parasitoids must search for their prey, they generally are very mobile and spenda considerable amount of time moving across plant tissue. This increases the likelihood that they will getin contact with the pesticide. They also feed on or live inside poisoned prey. In addition to killing naturalenemies directly, pesticides may also have sublethal effects on insect behavior, reproductive capabilities,egg hatch, rate of development, feeding rate, and life span.Related exercises from CABI Bioscience/FAO Vegetable IPM Exercise Manual:1.3 Spray dye exercise1.4 Effect of pesticides on spiders and other natural enemies1.5 Role play on insecticide resistance4-A.13 Comparison of biological and chemical pesticides used in caterpillar control4-D.8. Spot application of acaricides to manage mitesThe "International Code of Conduct on the Distribution and Use of Pesticides (Revised Version),2003", developed by FAO with participation of Government experts, NGOs, the pesticide industry andother United Nations organizations, established voluntary standards of conduct for all public and privateentities engaged in, or associated with, the distribution and use of pesticides. This Code of Conductsupports increased food security, while at the same time protecting human health and the environment.Since its adoption this Code of Conduct has served as the globally accepted standard for pesticidemanagement. Full text can be retrieved from: http://www.fao.org/AG/AGP/AGPP/Pesticid/A useful manual about organic agriculture (no use of pesticides and chemical fertilizers) is the "IFOAMTraining Manual for Organic Agriculture in the Tropics". This manual can be downloaded from:http://www.fibl.ch/english/publications/training-manual/preface.php68Eggplant Ecological Guide