Demonstration Study Of IPM On Corn Leaf Mites

This paper discussed the occurrence and damages of corn leaf mites in China, and reviewed the previous studies on it. Corn leaf mite was one of the secondary pests among the pests and diseases of crops in China. However, in recent years, the damage was becoming worse in the most northern districts, and in some areas the outburst of pest disaster is likely to occur. So it becomes one of the key pests in several provinces and autonomous regions like Xinjiang, GanSu, NingXia, ShanXi, HeNan, LiaoNing and so on, which affected the grain yield seriously. Now it's necessary for Agricultural departments at all levels and agricultural technological extention department to solve this problem and to popularize the control tactics of corn leaf mites among farmers as soon as possible.The paper discussed the appeared and endangerment of corn leaf mites and made clear the main species of corn leaf mites was Tetranychus urticae Koch in NingXia. In 1989, corn leaf mites occurred in some counties like PingLuo, TaoLe of NingXia, from then on the damage had spread the whole region, and the loss caused by the it was about from 15% to 20% above, which made the corn aged early in large areas.In recent years the damage of corn leaf mites became gradually severe, in corn fields in Yinchuan City of NingXia, the occurring rate is nearly 100%, 95-100% for average fields, and withered rate reaching 40-80%, all of these became critical problems for the corn product.The paper deliberated extension of the control tactics on corn leaf mites and put forward the IPM on corn leaf mites in NingXia for the first time, and demonstrated in large areas, which not only provided the practical technology but also offered the guide basis for the agricultural administrative department and agricultural technology extension sectors. The key control tactics are as follows: (1) Deal with the straw, in order to eliminate the over winter mites. (2) Breed resistant plant cultivars. (3) Excise the leaves at the bottom. (4) Apply 1-2 pesticide when 50% plants suffering damages. (5) Plow and irrigate in winter after harvest. From 2002-2003, in Yinchuan city of NingXia, this technology was demonstrated in 126062 Mu, and the integrated prevention efficiency achieved 93.7%, with an increase of 7.4% and 35.9 Kg/Mu. The increased cost is 10.3 Yuan/Mu with net profit 21.9 Yuan. The above results show that the technology was pragmatic for IPM on corn leaf mites in NingXia, and could be used for reference in other corn product areas.The agricultural extension mode fit for the control of corn leaf mites was constructed after 2 years demonstrations in the past. The major characteristics of the mode are as the following: government promoting and assigning tasks to different levels to the grassroots; multi-chanel technology training to farmers to master key tactics as soon as possible; intensifying the investment for the necessary materials and technology such as seeds, pesticides and plant protection machines as well as ensuring the implementation of the key tactics; government's offering subsidy for the technicians and farmer to arouse their initative; the efficient forecast and applying of chemical control according to the control index; carrying out contract for the agricultural technology and checking strictly before acceptance.This mode provided the agricultural department extension methods of control tactics of corn leaf mites with the help of national agricultural technology and extension sectors, which was also worth of reference for the extension of other single agricultural technology.