The Occurance Dynamics Of The Wheat Blossom Midge Sitodiplosis Mosellana (Gehin) In Guanzhong Area Of Shaanxi And The Determination Of Juvenile Hormone In Its Larvae In Different Stages

Wheat blossom midge, Sitodiplosis mosellana(Gehin)is one of the most important insect pests in the wheat production. It is widely distributed in Europe, Asia and North America and its disasters were recorded in many countries such as the U. S., Canada, England, Germany, Finland and so on. There have been two breakouts of the wheat blossom midge in 1950s and 1980s respectively in China. Serious damages caused by the wheat blossom midge have been restrained on a large scale in recent years, but a few serious injuries yet could be found in part areas. The wheat blossom midge is one of the most dangerous pests which should be monitored in wheat production at the moment.Guanzhong area of Shaanxi province is one of the most damaged areas of the wheat blossom midge in China. This paper deals with the occurrence dynamics of the wheat blossom midge in Guanzhong area of Shaanxi province in recent 20 years and its change of juvenile hormone III(JH3)determined by gas chromatography in different stages. The main research results are as follows.1. It could be found that the occurrence area of S. mosellana displayed an obviously decreasing trend in recent 20 years. The relative analysis the occurrence area was positively related very significantly with average temperature(X7) in March, and positively related very significantly with average temperature (X8) in April and annual temperature accumulation (X8) respectively.