Studies On The Characteristics Of Community Structure Of Stored Grain Insect In Export Agricultural Products And Pests Fumigation Treatment

This paper studied the characters of insects community structure, the temporal pattern and pests fumigation treatment of export agricultural products during 1997-2001. The main contents and conclusions are as follows:1. The grain stored insects of the export agricultural products had abundant community species and different community had obvious differences. 54 species of grain stored insects including 46 species of pests and 8 species of natural enemies were obtained through investigation. In which 7 new records in Shandong Province were found. The study of the stored grain insect communities of garlic and dehydrated vegetables was the first time hi china.2. The species' composition and relative abundance of insect's community of export agricultural products were analyzed. The community species mainly consisted of Coleopteran and Lepidoptera secondly. The above-mentioned 2 species made up the main body of this community in which initial pests dominated in number. Lariophagus distinguendus (Frster)and Microbracon hebetor Say had a great deal in the parasitic natural enemies while Chelifer sp. and Xylocoris galactinus Fieber were in large number among the predatory enemies. The species' composition of insect community had little differences and except garlic, the initial pests in the 5 kinds of export agricultural products were dominant in quantity.3. The numerical characteristics of insect community structure of export agricultural products were analyzed by the following indexes including species richness, ecological dominance, community diversity and evenness. While dominant population of stored grain insect communities were determined. By the method of hierarchical cluster analysis, the study of numerical classification was made and 5 communities were divided into 4 bigger groups. The characters of communities of the 4 groups were analyzed combined with characteristics of the community structure of stored grain insects, the occurrences of the pests and the natural enemies, and therelevant opinions of the grain management were made out.4. The temporal characters of the grain insects were researched by the characteristics of community structure and relevant pests control measures were made out according to the occurrences of the pests and natural enemies in different time.5. The study on the efficiency obtained by fumigation of methyl bromide to the dominant grain stored pests revealed that Sitotroga cerealella (Olivier) was sensitive to methyl bromide and had a weak drug-endurance and the drug-endurance of Sitophilus zeamais (Motschulsky) and Tribolium castaneum (Herbst) rose in turn while the treatment temperature went up, the CT value decreased.6. The characters and the influence factors, the relation between the community study and the management of stored grain insect community of the export agricultural products and the research of prevention and treatment were all discussed.