Study On Occurrence Regularity, The Method Of Prediction Of Adults, Analysis And Evaluation Of Resistance Of Wheat Midge, Sitodiplosis Mosettana (Géhin)

Wheat midge Sitodiplosis mosellana (Géhin) is a destructive pest over the world, also is one of the main pests in northern China. In recently years, S. mosettana, was occourced seriously in Hebei Province. The experiment for occurrence regularity, spatial distribution, prediction of S. mosellana, and resistance of wheat were carried out in the field in Xushui from 2009 to 2011, in order to provide the reference and instruction for prediction and integrated control. The main results are as follows:1. A field survey of the population dynamics of S. mosettana, was conduted from 2009 to 2010 in Xushui. The results showed that the overwintered larvae broken the cocoon and began to rise in the end of March. The larvae raise the soil surface and began to pupate when the wheat was booting in mid to late of April. The adult began to eclosion when the wheat was heading in the end of April. The peak abundance of adults occurred in the middle of May after which the population began to decline in the end of May. The larvae started to hatch after 6 or 7 days, and bounced in the soil after maturity. Most in the form of cocoon from the ground 0 to 7 cm of soil, partly existed the 7 to 14 cm of soil, and rarely presented in 14 to 20 cm. The larvae broken cocoon to rise again in the next year.2. The results of number of S. mosettana egg and larvae on different position of wheat ear showed that the numbers of S. mosellana egg and larvae in middle wheat ear were significantly more than the other two position, top wheat ear were significantly more than the lower (P<0.01). The most abundant eggs were lay between glume and palea, and numbers order to the other 3 position of wheat spikelet were as follows: between spikelet and rachis, between glume and lemma and outside palea. The methods of aggregate indexes, Iwao and Taylor models were used to test the spatial distribution of egg and larvae of S. mosellana on wheat ear. The results showed that egg and larvae on wheat ear belonged to aggregate distribution, presented an aggregated pattern, and its fundamental component was the group composed of several individuals that attracted each other. It was tested by aggregation and the aggregation of egg and larvae was determined by their own biological characteristics and environmental factors.3. Sticky plates of 14 colors and purple plate and yellow plate at the different three heights were used in the experiment. Results showed that the numbers of S. mosettana adults trapped by using sticky plates of purple, peach pink, orange-red, orange, light pink were significantly higher, besides most S. mosettana adults were trapped from the purple plate, which existed a siginificant difference with the yellow plate which was widely used in monitoring pests in production. Otherwise, the numbers of flies which were trapped by purple plate were significantly less. Results on the trapping effect of purple plate and yellow plate with different three hights showed that most of S. mosettana adults were trapped from the lower, which existed a significant difference with those from the other two hights (P<0.01). Moreover, the numbers of S. mosettana adults which were trapped in the purple plates were significantly more than yellow plates at the same height (P<0.05). Therefore, we suggested that purple plates can be used to monitor S. mosettana adults population dynamics, the height that the lower edge of the purple plate flush with soil surface was more appropriate.4. 284 wheat varieties which were nationwide plated were evaluated resistance to S. mosettana in the field. The preliminary results showed that 19 wheat varieties were frozen to death, the growth period of the 103 varieties of wheat and occurrence of S. mosettana do not coincide, and 162 were consistent. There was significant difference among 162 wheat varieties in resistance of S. mosettana. Immunization, high resistance, moderate resistance, low resistance, susceptible and highly susceptible varieties were 6.17%, 12.96%, 12.35%, 22.22%, 16.05% and 30.25%, respectively. There was significant difference in ratio of damaged ear, damaged seed estimated damaged and resistance index among 162 wheat varieties. After evaluated further into the 10 immune wheat varieties, 21 highly resistant wheat varieties and moderate resistant ones, they can be used in field production and breeding as dominant planting varieties and genetic resources in resistance to S. mosettana.The originalities of this paper were: (1) It was first time to population dynamics of S. mosettana was comprehensively investigated, and analysis spatial distribution of egg and larvae on wheat ear during the whole occurrence period in Hebei Province. (2) It was first time to define the taxis of 14 colors of S. mosettana adults, and purple sticky plates could be used for monitoring.