Preliminary Evaluation Of Integrated Benefit Of Resistance To Poplar Long-horned Beetle Disaster Of Different Tree Species Configuration

According to the natural environment, social conditions and situation of experimental field of the irrigated areas in "Ningxia, six types of configuration patterns with different tree species in farm windbreak were chosen to evaluate the integrated benefit of withstanding Poplar Long-horned Beetle (PLB) disaster with different tree species configuration, and the evaluation index system was also established.The anti-pest indexes including the number of impressions, frass holes and emergence holes, were used to evaluate the damaging degree of PLB in different periods. The result showed that anti-pest effect of target trees increased as the proportion of bait trees increasing. But on the other hand, it wasn't obviously different by the proportion of bait trees increasing, when the proportion of target trees attained to certain degree. So, the proportion of bait trees was not direct proportion to that of target trees and had certain limitation.By the method of combining the static and dynamic analysis, many methods were used to analyze economic benefit and its sensibility to increasing the veracity and rationality. The result showed that the pattern of "target trees + non-host trees+ bait trees" was better than the pattern of "target trees+ non-host trees", and the benefit of the pure target trees was the worst. The best one of economic benefit and the ability of anti-risk was "65 % target trees+ 25 % non-host trees+ 10 % bait trees".The ecological benefit in configuration patterns with different tree species were evaluated and compared with six types index system. As a whole, results showed that the multi- tree species configuration pattern was the optimum compared with that of the pure tree species.Analyzed 9 kinds of index of social benefit, it indicated that the best pattern was "target trees+ non-host trees+ bait trees" , but the pure trees pattern was not accepted by most farmers.Multi-target grey strategy decision method was taken to study integrated benefit of different tree species patterns. The result was that the pattern of "25 % target trees+ 25 % non-host trees+ 10 % bait trees" was the best. The threshold value was 0.948 which not only can resist PLB disaster, but also can assure optimized integrated benefit. However, that of the pure target trees was lowest and its threshold value was only 0.3692.Based on the theory of withstanding PLB disaster with different tree species configuration, the conclusion of evaluation and factors analysis of the target trees and bait trees, it concluded that rational proportion of bait trees was 7.093% - 25%. It also educed the concept and the model of withstanding disaster threshold of PLB disaster originally, which could instruct and apply to practical work. The model that was dynamic and flexible could be modulated by varying requests to target trees, damage degree of bait trees and rotation period.