A Slow Release Formulation Manufacture Of E-β-Farnesene Mixed With Methyl Salicylate And Its Effects On Wheat Aphids

Wheat Triticum aestivum,the most important food crop worldwide,has been damaged by wheat aphids for such a long run.Aphids not only grab plant nutrients and produce honeydew that can hamper plant photosynthesis,but also transmit virus causing yield loss and reducing wheat products quality.To control aphid pests,systematic pesticide applications were performed and it had led to many prominent problems such as chemical residues,target pest resistance and ecological disruptions etc..To ensure food and ecological security,some new technologies to control aphids based on ecological regulation and biological control should be investigated.The aphid alarm pheromone E-β-farnesene（EβF）,warning others of the presence of immediate danger,interferes the aphid feeding.It can repel aphids and attract some natural enemies in laboratory.Methyl salicylate（MeSA）is an important herbivore-induced plant volatile（HIPV）,and it is also a key signal in the plant defense responses.It can improve the plant resistance to pests,and manipulate insect behaviors.MeSA was effective to manipulate the behaviors of aphids and beneficials in wheat fields.Since EβF is volatility and easy to be oxidized in open air,field application was limited.So the EβF slow release beads were manufactured,the retention period and release rate were tested in laboratory.And then,the slow release formulations composed of the mixtures of EβF with MeSA in different proportions（10 mL MeSA,0.1 mL EβF+10 mL MeSA,1 mL EβF+10 mL MeSA）were designed and manufactured.Their ecological functions on wheat aphid and beneficials were assessed in 2018-2019.The main results are as follows:1.Release rate determination of EβF alginate beadAt room temperature（20℃）,EβF in paraffin oil(1 mg·mL^-1)released less than 2 days,whereas EβF in alginate beads released at least 15 days.The EβF in the slow-released alginate beads can released slow and uniform,and the release rate of EβF alginate beads was 0.198L·d^-1.2.Ecological functions of EβF and MeSA on wheat aphidsIn 2018,the abundance of apterous aphids and alates significantly decreased in the bead-treated plots（10 mL MeSA,0.1 mL EβF+10 mL MeSA,1 mL EβF+10 mL MeSA）compared with the control.Among which,0.1 mL EβF+10 mL MeSA had a significant effect on apterous S.avenae compared with the other treatments.In 2019,the ecological effect of the candidate ratio of 0.1 mL EβF+10 mL MeSA on apterous aphids was significant,but there was no significant difference on alates.3.Ecological functions of EβF and MeSA on beneficialsIn 2018,10 mL MeSA,0.1 mL EβF+10 mL MeSA and 1 mL EβF+10 mL MeSA can significantly increase the abundance of lacewing,hoverfly in wheat field.In 2019,the ecological effects of the candidate ratio of 0.1 mL EβF+10 mL MeSA on lacewing,hoverfly had significant difference.