Studies On The Community Structures And Population Dynamics Of Mulberry Insect Pests-natural Enemies

According to a recent systematic survey in Mulberry pests-natural Enemies, combining with Mulberry bearing period, the situation of plucking leaves and controlling pests, and the main Li Town weather datum, the structures community and seasonal population dynamics of pests-natural enemies were analyzed.The amount and species of Mulberry pests and natural enemies obey the obvious seasonal ebb and flow law, basely presenting a single-aped curve in the whole year, basely according with the curve of month-average temperature in Li town and Mulberry' s leaves season-yield in the whole year, in correlation to the plucking of Mulberry leaves, pesticide controlling, month-sunlight period, month-rainfall, and so on. The law of ebb and flow in Mulberry natural enemies and pests is basely identical, representing the obvious pursuing phenomenation among Mulberry-pests-natural enemies.Mulberry pests sub-community always remains very high level of species abundance and predominance of community zoology in the whole year. There are greater differences each month in community diversity index and community evenness index of Mulberry pests-natural enemies. Few of pests have distinct predominance, especially in Pseudoden drothripsmon Niwa, Diaphania pyloalis Walker, Pseudau-lacaspis Pentagona.Mulberry in Li town can be distinctly classified into four stages: the first stage is from November to the next March, Mulberry communities are all in the rest period. The second stage is from April to June, namely, the community activity period. The third stage is from July to September, which is the community fluctuating period. The last stage-the whole October is the community transition period.In Mulberry beyond the chemical shield, the amount and species of pests are more than ones of natural enemies. Natural enemies and pests live only in the proportion of 1:29.2. So pests are less in the control of natural enemies, the dynamics stability of Mulberry pests-natural enemies community is destroyed, forming a malignant cycle in prevention and cure. Therefore, not chemical pesticide shield but the compositive control measure, especially zoology control, is suitable to Mulberry pests, realizing continuable development of silkworm-Mulberry industry.