| Thiacloprid belongs to the second generation of new neonicotinoid insecticides after imidacloprid,it can also stimulate the crop growth,improve the ability of disease resistance,induced a variety changes of physiological crops,besides insecticidal effect.The wheat aphid is an important pest of wheat,which is widely distributed,having feeders miscellaneous and strong fertility.It can decrease the production and even have no harvests.In addition,wheat aphids can also spread a variety of wheat toxoid diseases.To control wheat aphid with coating,imidacloprid and thiamethoxam of new neonicotinoid are mainly used.But the research shows that imidacloprid and thiamethoxam are both with high toxic for natural enemies of wheat aphid,bees and other non-target organisms,while the thiacloprid with low toxicity to bees,which is safe of the bees.This subject mainly researches effect of the physical growth and yield of wheat coated with thiacloprid,and the control effect of wheat aphid and the influence of it's natural enemies with seed coating or mist spray of thiacloprid.This experiment mainly studied the influence of germination,growth and yield of wheat which coated with thiacloprid in laboratory and in the field.We also studied the control effect of wheat aphid and the influence of it's natural enemies with both seed coating and mist spraying of thiacloprid.This experiment aims to provide theoretical support of thiacloprid application on wheat.1.The experiment studied the effect of thiacloprid seed dressing on the germination and growth of wheat in laboratory.Result shows that active ingredients in 24 g a.i./10 kg seed doses of thiacloprid has no unhealthy effect on germinative force and germination rate of wheat,while it can improve wheat germination index and vital index.It also can obviously improve the wheat seedling chlorophyll content,root activity and the activity of protective enzyme,such as superoxide dismutase(SOD),peroxidase(POD)and catalase(CAT).ect.The study confirms that thiacloprid seed dressing can improve the defense capability of the seedling,enhance the capacity of resistance,reduce the wheat damage degree,reduce peroxidation level of cell membrane lipid,and significantly improve seedling growth.2.In laboratory,wheat is cultivated by hydroponic method,and aphids dip method and systemic bioassay were used respectively to study the most effective dosage of thiacloprid on wheat aphid prophylaxis and treatment.Author also determined the toxicity function of thiacloprid on harmonia axyridis by means of adult release drug membrane method and larvae drop method in laboratory.Results show thiacloprid of wheat aphid has very good activity,and the harm to harmonia axyridis regard as wheat aphid natural enemies which comes from thiacloprid is obviously lower than that of imidacloprid.3.In field trials,author studied the promting effect of thiacloprid coated on wheat,and researched the influence of thiacloprid on yield,control efficiency about wheat aphid and natural enemies by means of seed dressing.Experimental results show that: active ingredients in 24g/10 kg seed of thiacloprid is the best dose.It can promote wheat root length and root number,increase root-shoot ratio of wheat,tiller number and underground fresh weight,and can also obviously increase the spike number,kernels per spike,thousand seed weight and yield.The control effect of Thiacloprid seed dressing on wheat aphid can be lasting by improving the film-forming agent.But test was carried out in the field,showing that the concentration of test spraying on wheat achieved a good control effect on aphid and had little harm for aphidiidae which belongs to the natural enemy of wheat aphid. |
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