Effects Of Exogenous Application Of Methyl Salicylate And Oligosaccharins·plant Activator Protein On The Population Dynamics Of Aphids And Main Natural Enemies In Wheat Fields

Wheat Triticum aestivum L.is one of the most important grain crops in China.Because of wheat insect pests,especially the damage of wheat aphids,wheat product has been seriously damaged.The main way to control wheat aphids in fields is to spray pesticides such as imidacloprid.But with the economic development,much attention is paying to environmental protection.Many pesticides with serious environmental pollution are also banned each year.In addition,with the long-term use of pesticides,the resistance of wheat aphids is also increasing.So much effective and environmentally friendly way need to be developed for aphids management.Methyl salicylate(MeSA),as one of the herbivore-induced plant volatiles(HIPVs),can effectively repel wheat aphids.At the same time,there has been a relatively stable and effective field slow release technology to release MeSA in fields,such as alginate slow-released bead.But its specific volatilization effect needs further determination.Oligosaccharins·plant activator protein as an elicitor can improve the resistance of wheats to aphids.In this experiment,the specific release rate of a new MeSA slow-released bead was measured by the laboratory volatilization test.The MeSA and oligosaccharins·plant activator protein were combined to be applied in wheat fields.Its effects on non-target arthropods in wheat fields were also clarified to avoid any side effects on non-target organisms.We used air tightness device to collect volatile and determined the specific release rate of MeSA by GC.A two-year field experiments were conducted to explore the interaction between MeSA and oligosaccharins·plant activator protein on arthropod in wheat fields.The results are as follows:The MeSA slow-released bead had at least 15 days at a constant rate of volatilization.And the rate of constant volatilization is about 2.37 ?L/ day,while the control of pure MeSA was out of volatilize in seventh days in lab.In field experiments in 2016,two-factor analysis of variance(two-way ANOVA)showed that MeSA,oligosaccharins·plant activator protein and the interaction of the two factor could significantly reduce the population of apterous and alatae aphids,but the effects were similarto total aphids.The MeSA had a significantly attraction to the hover flies and the lacewings.It also had a extremely significant attraction to the coccinellids.The MeSA had no significant influence on the parasitic wasps.oligosaccharins·plant activator protein had no significant influence on the natural enemies,and the interaction of the two factors on the natural enemies was not significant.MeSA,oligosaccharins·plant activator protein and the interaction had no significant effect on the abundance of ground arthropods such as spiders,ground beetles and click beetles.In the field experiments in 2017,MeSA,oligosaccharins·plant activator protein and the interaction of the two factors could significantly reduce the population of alatae aphids.Only oligosaccharins·plant activator protein could significantly reduce the number of apterous aphids,while MeSA and the interaction had no significant effects.The same effects on natural enemies were found as in 2016.