Spatial Pattern Of The Wheat Midge Sitodiplosis Mosellana (Gehin)

Wheat midge Sitodiplosis mosellana (Gehin) (Diptera, Cecidomyiidae) is one of destructive pest over the world. The larvae feed on the developing kernel of the wheat, which cause wounded or total loss of wheat grain and lead to wheat production drawdown or total destruction.The spatial pattern of the wheat midge was studied in the thesis, the experimental field was located in Luoning County, Luoyang City, Henan Province, where the wheat midge occurred frequently every year (more than 20 per small square in the soil). It is the first time to use geostatistics combined with traditional methods to obtain the spatial pattern of wheat midge, in order to provide the reference and instruction for insect population density survey, prediction and integrated control. The results are as follows:1. The spatial pattern for the large scale of the adult.The line chart was used to describe the features that the population is larger in the west than in the east. And then geostatistics was used to analyze spatial pattern of large scale for the wheat midge. The results showed that the correlation distance was 42 km. It suggested that it should be less than this range when we choose distance between two samples, which was better to reflect the facts.2. The spatial pattern for the active height of the adult.The column diagram was used to describe the active height of the adult, which showed that there were two peaks in the 15 cm and 45 cm, which were the main rest area and the main egg-laying area of the wheat midge. And then geostatistics was used to analyze spatial pattern of the flight height of the adult. that the correlation distance was 53 cm. It suggested that it was the suitable spray height on the wheat, which can be more cost-effective.3. Spatial pattern for the different stage of wheat midge.(1) Aggregation index analysis: the distribution pattern was aggregated distribution in all stages of the wheat midge.(2) All the semivariogram in the direction of West-East were of the same model and the model in the direction of North-South were similar. It showed that the special pattern in each phase of the wheat midge kept stable and had their own feathers. In the North-South direction, larvae are spherical + exponential model, while the adults are spherical + spherical model. To compare to the two models, the spherical model is a typical aggregation distribution model. It indicated that the adults preferred to gather together more than the larva. Field observations also proved that the wheat midge adults preferred group activities.(3) The correlation among the three different stages of the wheat midge in the same space was analyzed with Pearson Correlation, which showed no correlation between them. This proved that the wheat midge did not stay in the same place, but move according to environmental characteristics and their situation.The originalities of this paper were: (1) It was the first time to use the yellow plate to trap wheat midge to analyze the spatial pattern of the adult. which concluded that adults like congregate, which was consistent with the results of field observations. (2) It was the first time to use geostatistical method to study the distribution pattern in different altitudes, and to get the spatial pattern of the wheat midge and try to explain its "island-type" distribution characteristics.