Alternative approaches in pest control: studies on major pests of litchi in the mountainous regions of Northern Thailand

Agriculture in mountainous northern Thailand faces the challenge of increased pressure on Iimited agricultural land due to high population growth, accompanied by a rapid change fram shifting cultivation and fallow practice to permanent agriculture in marginal regions. The production of highvalue agricultural commodities, especially Iitchi fruits (Litchi chinensis Sonn.), have become an important source of cash income for small-scale farmers in that area. However, the market orientation led to the extensive application of agricultural chemicals such as synthetic fungicides, herbicides, insecticides and fertilizers, resulting in considerable contamination of soil and water. Especially from the application of pesticides, weil known problems such as resistance of pests, toxicity to non-target organisms (including man) and other environmental effects may result. Therefore, alternative control options are required, especially in small-scale Iitchi production systems. The objective of this study was to provide pest management strategies for the major arthropod pests attacking Iitchi in northern Thailand in order to develop an operational basis for a sustainable litchi growing system. To this end, the following steps were taken: (i) determination of the major pests of Iitchi in the study area from 2004 to 2006; (ii) identification of the development cycle including times and stages of the target pests; (iii) selection of possible biological control methods and selective pesticides in order to control the recorded major pests; (iv) development and improvement of environmental save application strategies in the Iitchi growing system; (v) evaluation of use efficiency of selected pesticides, entomopathogenic control agents and applications strategies on the major pests of Iitchi.