| Corn is one of China’s major crops, which has a long history of cultivation. Shandong Province is located in the middle and lower reach plain of the Yellow River, which is the main summer maize growing area because of the superior geographical environment and climate. But with the global climate warming, the summer rainfall increasing and growing of new compact-typed varieties of summer corn, the new tendency of diseases and insect pests on corn appeared, and the damage degree of corn production increased year by year.In order to illustrate the spatio-temporal patterns of the main insect pests in corn field and further analyze the distribution of pests in Shandong Province, this research investigated the population dynamics of small brown planthopper, Laodelphax striatellus (Fallen) and the yellow peach moth, Conogethes punctiferalis (Guenee), and analyzed the spatio-temporal distribution of the two pests using the geostatistics method to provide the basis for the field systematic sampling and management of the pests. The distribution of Conogethes punctiferalis, Ostrinia furnacalis, Chilo sacchariphagus and Helicoverpa armigera was made by using GIS, supplying reference for insect pest forecast and integrated control.1. The trapping effectiveness of different colored sticky cards attracting small brown planthopper in spring corn fieldsThe trapping effectiveness of six types of colored sticky cards, including yellow, white, red, blue, green and light-green ones, for small brown planthopper, was investigated in spring corn fields. The population dynamics of the planthopper was analyzed. The planthopper significantly preferred yellow cards to others(P<0.01). During the survey, the number of the male small brown planthopper was always larger than that of the female individuals, accounting for72.49%of the total. In the thriving occurrence periods, the sex ratio of the females to males was0.44:1. All the results showed that the yellow sticky card is the most effective one for monitoring and controlling the planthopper.2. The spatial pattern analysis of L. striatellus adults in corn fieldsThe spatio-temporal dynamics of small brown planthopper (SBPH), L. striatellus in12corn plots were analyzed using the geostatistics method, which was compared with the traditional statistics method. Two kinds of analysis results were a little different, but the overall performance was aggregated distribution. In geostatistics method analysis, the aggregation degree of the planthopper adult population in plot2,3,4and8were very high, but the spatial correlation between each sampling point didn’t exist, which presented random distribution. And the others all presented aggregated distribution. The spatial distribution of the population was simulated using the geostatistics method. The results showed that the aggregation center of the small brown planthopper adults was located in the north and south of a plot. The reason was caused by the biological characteristics of the small brown planthoppers and environmental factors.3. The spatio-temporal patterns of C. punctiferalis larvae in corn fieldThe population density of C. punctiferalis larvae was growing up with the development of summer corn, and peaked on Sep.4th, then decreased as larvae began to pupate. According to geostatistics analysis, the spatial pattern of C. punctiferalis larva was random (Aug.16th), aggregative (Aug.20th to Sep.11th), and random (Sep.16th) distribution in the temporal sequence, respectively. The population of C. punctiferalis larvae in the sample plot showed distinct spatial dependence. Its interpolation maps showed that the aggregation center of C. punctiferalis larvae was located in the north and south of a plot. The reason was caused by the interference of the surrounding environment, and the pest control was focused on adults and eggs.4. Niche analysis and Population density based on GIS of four insect populations on summer cornThere were significant difference in the number of3species of pyrilid caterpillars in different areas, and the proportions of the C. punctiferalis and Ostrinia furnacalis were more than that of other pests. But the cotton bollworm was discovered in some areas. The niche breadth and niche overlap of3pyralid caterpillars were significant different, which were very large. But the main damage part of cotton bollworm was female ear, and its niche breadth was1. The population density maps obtained from GIS can intuitively show four pests presented a strip-shaped aggregative distribution. The maps of population density distribution of four pests showed that the occurrence of C. punctiferalis in middle and eastern was more seriously, especially in Tai’an, and in southwest and northwest areas this pest occurred lightly. The number of O. furnacalis was markedly reduced from west to east, and this pest occurred more seriously in southwest and northwest areas, especially in Liaocheng, Deizhou, Heze and Zaozhuang. The occurrence of Chilo sacchariphagus (Bojer) and Helicoverpa armigera (Hiibner) was more lightly.5. The population dynamics of C. punctiferalis and O. furnacalis adults using the pheromone lures in Shandong ProvinceThere were significant difference in the number of D. punctiferalis and O. furnacalis adults, and except Weihai, the number of O. furnacalis adults was significantly more than that of D. punctiferalis adults. It showed that the occurrence of O. furnacalis was more common and serious in Shandong Province. The maps of population density distribution using MapGIS6.7intuitively showed that the occurrence and distribution of pests were region-specific. The population density of D. punctiferalis in July, August and September had little difference, but the populations in Taian and Weihai were larger. O. furnacalis was the main pests on corn, its population density was similar month by month. The occurrence of O. furnacalis was more serious in west parts than in east parts, especially in southwest and northwest of Shandong Province. |
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