Design And Application Of Electrospun Controlled Release Attractant For Spodoptera Litur

Spodoptera litura(S.litura)is a polyphagous pest of Lepidoptera,which has caused great damage to agricultural production worldwide.Insect sex pheromones are used in the monitoring,trapping and interfering mating of S.litura because of their small usage,high efficiency,and green environmental protection.However,the high volatility and chemical instability of pheromones limit its efficient application in the field.At present,carrier technology is one of the main methods to prolong the duration,but there are still problems to be solved urgently in the existing carriers such as sudden release and fast release.Electrospinning technology can efficiently prepare micro-nano fibers,which have become a research hotspot in drug sustained and controlled release carriers.However,the design of fiber carriers for pheromones based on electrospinning technology can improve the release behavior,and the concept needs to be validated by extensive indoor and field trials.Therefore,this study used electrospinning technology to design a fiber-type sustained-release sex attractant for S.litura,and carried out actual field trials.The details are as follows:(1)Fully biodegradable polyhydroxybutyrate(PHB)was used as the carrier material,and the pheromone-loaded fiber films with different carrier concentrations were prepared by uniaxial electrospinning.The results showed that the pheromone-loaded fiber has good morphology and structure,the pheromone loading could reach 14.84%,the release time of pheromone in the fiber carrier could be up to80 days,and the release behavior was fitted to first order release kinetics.Field test results showed that the fiber-type sex attractant could continuously trap S.litura for more than 7 weeks and could degrade naturally.(2)Environmentally friendly polycaprolactone(PCL)and PHB were used as carrier materials(PHB was the protective shell layer,PCL was the core layer load pheromone),the core-shell structure of the pheromone-loaded fiber film was prepared by coaxial electrospinning.The encapsulation rate of pheromone by core-shell fiber is75.79%,and the fiber has hydrophobicity and low light transmittance.The release test results showed that the structure successfully inhibited the early burst release of pheromone,and the release time could reach 133 days,and the field test results showed that the trapping ability of core-shell fibers was better than commercially available rubber carriers.In summary,the insect sex pheromone carrier of S.litura designed and prepared by electrospinning technology in this study has good physical and chemical properties,sustained-release and trapping ability,and has great significance for the integrated pest management of S.litura and the application of green pesticides in the field.