The Safety Evaluation For Imidacloprid In The Wheat Seeds And The Ecological Pest Management To Aphid

1. The residues of imidacloprid in wheat seeds were determined by UPLC-MS/MS,the wheat seeds were dressed with imidacloprid in the proportion of2、4、6、and8mg/kg.The results showed that the residues of imidacloprid increased as the proportion increased,the residues in the seeds dressed in the proportion of8mg/kg were the highest(0.029mg/kg).The results were lower than the limit of residues in the seeds (0.05mg/kg) in America.Variance analysis showed that the residues in the seeds dressed in the proportion of8mg/kg presented very significant difference compared with the seeds dressed in the proportion of2、4mg/kg(p<0.01); the residues in the seeds dressed in the proportion of8mg/kg presented significant difference compared with the seeds dressed in the proportion of6mg/kg(p<0.05); the residues in the seeds dressed in the proportion of6mg/kg presented significant difference compared with the seeds dressed in the proportion of2mg/kg(p<0.05).2. Life tables of Macrosiphum avenae Fabricius were constructed on the seeds harvested from the dressed wheat and compared with the seeds dressed nothing.the results showed that there was no significant difference.this sufficiently proved the safety of imidacloprid.3. In2010and2011, the experiments were carried out on the relationship between the quantity of Aphids and the population of Coccinella septempunctata in different sowing time. The Coccinella septempunctata immigrated earlier when the wheat sowing time was normal, the population of the Aphids was small, the growth was slow; the Coccinella septempunctata immigrated later when the wheat sowing time was delayed, the population of the Aphids was big,the growth was fast.lt was a outbreak for the Coccinella septempunctata in the wheat field in2011,the Aphids had been controlled at flowering stage.4. Allothrombium ovatum was a kind of parasitical natural enemy that control wheat aphids. The largest number of Allothrombium ovatum we found was30±7.5per100plants. Allothrombium ovatum preferred dry and windy environment. There were more Allothrombium ovatum in sparse wheat field.