The Loss Assessment Of Grassland Caused By Oedaleus Decorus Asiaticus

Locust is a pest which occurs all around world. Recently, because of the change of global climate, the active of human, and improper using for natural resources, the ecological condition has be havocked, which make the plague of locust much more severity. For make more logical control for locust, it is need make a logical estimate of loss and establish a logical control index for locust which base on ecological and economic direction.This experimentation land is in the hinterland of KeErqin grassland. We carve the experimentation land up to four habitat: the representative grassland, the side of the river, the transiton band between the river and the representative grassland, and the interleaving of the herd and the farming. We researched the diversity index of the insect of this four habitat, and analyses the distributing of four predominance locust in the different habitat. The result shows that the count of the insect that be researched is 33 kinds. in that, 11 kinds is belong to orthoptera. 12 kinds is belong to predatism insect. 9 kinds is belong to Other berbivore insect. 2 kinds is belong to corrupt food habit insect. And 2 kinds is belong to other insect. And we are account the Shannon-winner index, the simpson index and the equality index of the insect community in this four habitat. The result shows that there is no distinctness differents that the Shannon-winner index and the simpson index in this four habitat. But the equality index of the insect in the interleaving habitat is lower than other habitats. The important value of four kinds of locust in the four habitat is differents, because of the different environmental condition and plant in the four habitat.we are use the method that to build the cover in the grassland, to examine the damage of Oedaleus decorus asiaticus in different growth step and different density for the grassland in the representative grassland. The results show that the compensation growth will be cause when the grassland have a small damage. And we are observe the consumption per Oedaleus decorus asiaticus that be put in the different RH per day for 4 kinds of plant which is stand for this grassland. The results show that the consumption of Oedaleus decorus asiaticus in the 50～80%RH is much more than other RH. And to refer to the grass weight in the different treatment, we are fit the damage-grass weight los curve, and get the damage reception curve of compensation type of the grass in this grassland. Before the extreme value of the compensation: Y1=14／(1+e^{3.44828+2.14034x}) (Y1: compensation value, x: consumption value), After the extreme value of the compensation: Y2 =((117.5+14)·x^-2.95248)／(0.00098+x^-2.95248)-117.5 (Y2: loss value, x: consumption value)we are appraise that the affect of the damage of Oedaleus decorus asiaticus in the different age and different density to the yield of grassland. The result shows that, In the experiment of cover, the 3 age and 4 age Oedaleus decorus asiaticus is no damage for grassland when the density is under 15/m², but in the experiment of manual simulation, 4 age has damaged for grassland when the density is 15/m²; if continue the damage to the adult, even though the density is very low such as 5/m², also be damage for grassland because the productivity of the grassland is very low when the Oedaleus decorus asiaticus in adult. The contol index of this grassland is between the 5 and 15, because the result of the experiment of cover and manual simulation. And the suit date to control for Oedaleus decorus asiaticus is 3 age.We are work out the ECT of the Oedaleus decorus asiaticus in this grassland that use the expressions: ECT=((-1)／(E×LnR))×(B+(CC)／(FL_n×P×EC)) wihich is built by YuMing (2006). The value of E is 1 in this page, the value of R we can know that use the camera, the value of B is the allow live count of the Oedaleus decorus asiaticus in this grassland, we can kown that use the expressions: the overall damage of the Oedaleus decorus asiaticus=the overall growth of the grass. The part of (CC)／(FL_n×P×EC) is the tradition ET model. This expressions give attention to the income of both the ecology and the economy. And in final, we can see that the ECT of Oedaleus decorus asiaticus in this grassland is 11.04, and it is more nicety than the tradition economic threshold.