ADVERSE EFFECTS ON FLORA AND FAUNA FROM USE OF ORGANOCHLORINE PESTICIDES IN A MAIZE AGROECOSYSTEM

摘要

Organochlorine pesticides have been used widely to manage insect pest problems in agriculture, forestry, and animal and human health. Most of these pesticides are also known to persist in the environment for long periods of time. It has been reported that this persistence is deleterious to animal and human life, and for this reason most of these pesticides have been banned in many countries, including DDT, gamma-HCH (lindane), dieldrin, endrin, toxa-phene, heptachlor, chlordane and endosulfan. However, in other countries, e.g. the United Republic of Tanzania, some of these insecticides (endosulfan and lindane) are still registered for use in agriculture. Since no information is available locally on the effect of these chemicals on the environment in which they are used, this study was conducted to generate data on the effects of lindane spraying on the arthropod fauna of field maize. The results indicate that lindane caused significant adverse effects on most of the early season beneficial arthropod fauna, particularly Collembola, ants and spiders. Mid and late season beneficial arthropod populations, including ants, spiders and ladybird beetles, were only slightly affected. The buried leaf litter decomposition rate was slightly reduced in sprayed compared with unsprayed maize fields.