This paper proposes a pest propagation model to investigate the evolution behaviours of pest aggregates. A pest aggregate grows by self-monomer birth, and it may fragment into two smaller ones. The kinetic evolution b...This paper proposes a pest propagation model to investigate the evolution behaviours of pest aggregates. A pest aggregate grows by self-monomer birth, and it may fragment into two smaller ones. The kinetic evolution behaviours of pest aggregates are investigated by the rate equation approach based on the mean-field theory. For a system with a self-birth rate kernel I（k） = Ik and a fragmentation rate kernel L（i,j） = L, we find that the total number MoA（t） and the total mass of the pest aggregates MA （t） both increase exponentially with time if L ≠ 0. Furthermore, we introduce two catalysis-driven monomer death mechanisms for the former pest propagation model to study the evolution behaviours of pest aggregates under pesticide and natural enemy controlled pest propagation. In the pesticide controlled model with a catalyzed monomer death rate kernel J1 （k） ---- J1 k, it is found that only when I 〈 J1 B0 （B0 is the concentration of catalyst aggregates） can the pests be killed off. Otherwise, the pest aggregates can survive. In the model of pest control with a natural enemy, a pest aggregate loses one of its individuals and the number of natural enemies increases by one. For this system, we find that no matter how many natural enemies there are at the beginning, pests will be eliminated by them eventually.展开更多
In order to uphold the basic policy of its state of agriculture basis,the Qin Imperial Government,regarding the prevention and control of the crop insect pests,had accumulated many measures to cope with them.For examp...In order to uphold the basic policy of its state of agriculture basis,the Qin Imperial Government,regarding the prevention and control of the crop insect pests,had accumulated many measures to cope with them.For example:to make laws and lay down the rugulations,to give full play to the organizing function of the local authorities,to mobilize or force the masses to participate in,to explore the methods and techniques of prvention and control as well as to carry out various kinds of activities to relieve the people in stricken areas.These measures were all-round and effective when the production and science were still of very low level,which,beyond doubt,played a very important role in ensuring and promoting the advancement of the agricultural production in Qin Dynasty.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10875086 and 10775104)
文摘This paper proposes a pest propagation model to investigate the evolution behaviours of pest aggregates. A pest aggregate grows by self-monomer birth, and it may fragment into two smaller ones. The kinetic evolution behaviours of pest aggregates are investigated by the rate equation approach based on the mean-field theory. For a system with a self-birth rate kernel I（k） = Ik and a fragmentation rate kernel L（i,j） = L, we find that the total number MoA（t） and the total mass of the pest aggregates MA （t） both increase exponentially with time if L ≠ 0. Furthermore, we introduce two catalysis-driven monomer death mechanisms for the former pest propagation model to study the evolution behaviours of pest aggregates under pesticide and natural enemy controlled pest propagation. In the pesticide controlled model with a catalyzed monomer death rate kernel J1 （k） ---- J1 k, it is found that only when I 〈 J1 B0 （B0 is the concentration of catalyst aggregates） can the pests be killed off. Otherwise, the pest aggregates can survive. In the model of pest control with a natural enemy, a pest aggregate loses one of its individuals and the number of natural enemies increases by one. For this system, we find that no matter how many natural enemies there are at the beginning, pests will be eliminated by them eventually.
文摘In order to uphold the basic policy of its state of agriculture basis,the Qin Imperial Government,regarding the prevention and control of the crop insect pests,had accumulated many measures to cope with them.For example:to make laws and lay down the rugulations,to give full play to the organizing function of the local authorities,to mobilize or force the masses to participate in,to explore the methods and techniques of prvention and control as well as to carry out various kinds of activities to relieve the people in stricken areas.These measures were all-round and effective when the production and science were still of very low level,which,beyond doubt,played a very important role in ensuring and promoting the advancement of the agricultural production in Qin Dynasty.
