Study On Population Dynamics Model Of Citrus Psyllid With Resistance Development

Citrus psyllid has a devastating damage to the sustainable development of the citrus industry,and dy-namic models can better describe the growth and decline of the psyllid population,and then evaluate the prevention and control effect of Huanglongbing.In order to study the effects of single chemical control and integrated chemical biological control on the number of citrus psyllid,we establish dynamic models of psyllid control with the development of physiological and behavioral resistance.Specific contents are summarized as follows:In the first chapter,the research background and significance of citrus psyllid,the research status at home and abroad of physiological and behavioral resistance of citrus psyllid,the development of pest resis-tance and resistance management are briefly introduced,and the preliminary knowledge that will be used in this paper is also given.In the second chapter,a single chemically controlled kinetic model of psyllid is established with the development of physiological and behavioral resistance.The extinction of psyllids is proved,and two criteria for optimal switching time of psyllids are proposed based on dynamic threshold condition R₀(n,T)and e-conomic hazard level(EIL).Finally,the models are compared from the perspective of whether physiological and behavioral resistance are considered or not.It concludes that if only physiological resistance is consid-ered,the population number of psyllid will be underestimated.Otherwise,if only behavioral resistance is considered,the population number of psyllid will be overestimated.Numerical simulations are used to verify the corresponding theoretical results in this chapter.In the third chapter,because the integrated control can achieve better results in pest management,so dynamic models of integrated control of psyllids with the evolution of physiological and behavioral resistance are established.Firstly,we prove the extinction of psyllids.Secondly,when the threshold condition of psyllids population extinction is reached,we study the analytical formula of the number of natural enemies to be released and the optimal time of spraying pesticides for two different control strategies.And we conclude that the switching time of insecticides will be delayed if behavioral resistance is not considered.Finally,numerical simulations are carried out to illustrate theoretical results.