Efficacy Of 50% Flonicamid·Pymetrozine WG Etc Against Aphis Gossypii Glover And Toxicity To Nontarget Organisms

As one of the most destructive pests on the earth,aphids have extensively harmed agriculture,forestry,horticulture and other industries.Aphis gossypii Glover,a kind of Hemiptera insect,has caused serious damage to vegetables of the Cucurbitaceae family.By sucking plant juice and excreting honeydew,it causes plant dysplasia,breeds mold,and can spread plant virus diseases.At the same time,due to the serious overlap of its generations,once it is not timely controlled,it may occur in a large area,which seriously affects the quality of the vegetables.In order to effectively control the occurrence of Aphis gossypii Glover on the cucumbers in greenhouse,improve the efficiency of prevention and control,and achieve the chemical prevention goal of high-efficiency and low-toxicity,this research is based on the result of screening synergistic insecticides for Aphis gossypii Glover from the indoor bioassay of this subject.Using water-dispersible granules?WG?of flonicamid and pymetrozine as contrasts,we continued to explore the effects of formulations and application methods about flonicamid·pymetrozine 1?1,2?3 on the control of Aphis gossypii Glover.And we also explored the toxicity to two non-target organisms,bees and earthworms.The main results are as follows:1.potted testThe efficacy of three kinds of flonicamid·pyrxidone preparations?50%flonicamid·pymetrozine WG?1?1?,50%flonicamid·pymetrozine WG?2?3?,20%flonicamid·pymetrozine SC?1?1??were determind by potted method in greenhouse.The test results show that the efficacy of flonicamid·pyrxidone's mixtures is better than the single flonicamid and pymetrozine at the test concentrations of 25 mg/L,50 mg/L,and 75mg/L,Showing good quick-acting and sustained effect.At the test concentration,one day after treatment,the control effects of the three flubendicarb·pymetrozine's preparations was more than 40%except for 25 mg/L 50%flonicamid·pymetrozine WG?2?3?.Seven days after the treatment,the control effects of the three flonicamid·pymetrozine preparations were above95%.The poor quick efficacy of 25 mg/L 50%flonicamid·pymetrozine WG?2?3?may be related to the mechanism of pymetrozine's action.From the perspective of formulations,there was no significant difference in the efficacy of 50%flonicamid·pymetrozine WG?1?1?on day 1,3,and 7 compared with that of 20%flonicamid·pymetrozine SC?1?1?.From the point of ratio,50%flubendicarb·pymetrozine WG?1?1?and 20%flonicamid·pymetrozine SC?1?1?in one day after applying is superior to the control effect of 50%flonicamid·pymetrozineWG?2?3?,but the difference in the effectiveness of the two ratios gradually decreased in 3days after applying.By the seventh day,the control effect of 50%flonicamid·pymetrozine WG?2?3?is even slightly better than the other two preparations with a ratio of 1?1.2.field testThis experiment mainly used spraying and root-irrigation two methods to test the field efficacy of the three preparations of flonicamid·pymetrozine.In order to further clarify the differences between the formulations,application methods and ratios.Compared with the potted test,the test dose of the agents was reduced in this field control test.The test results showed that compared with the spray treatments,50%flonicamid·pymetrozine WG?2?3?was irrigated at a test dose of 7.5 g a.i/hm² and 15 g a.i/hm² after the application of 3,7,14days can show higher prevention effects.Comparing the two application methods of 20%flonicamid·pymetrozine SC?1?1?,the root-irrigation treatment was just better than the spray treatment at 3 days after the test dose of 7.5 g a.i./hm².The 50%flonicamid·pymetrozine WG?1?1?and the two single-agents spray treatments were better than the root treatments.In terms of formulations,compared with the spray treatment of 50%flonicamid·pymetrozine WG?1?1?,the spray treatment of 20%flonicamid·pymetrozine SC?1?1?had a poor effect at the test dose of 7.5 g a.i/hm².When the test dose were 15 g a.i/hm² and 22.5 g a.i/hm²,the control effect of spray treatment was not significantly different from that of water-dispersible granules.However,the control efficiency of each root irrigation treatment of 20%flonicamid·pymetrozine SC?1?1?was significantly lower than that of 50%flonicamid·pymetrozine WG?1?1?.Compare with the results of three field control efficacy surveys:among the three preparations,50%flonicamid·pymetrozine WG?1?1?were the best in both quick-acting and sustained-effect when used in spray application,and in root-irrigated treatment,they were also the best quick-acting.And the 50%flonicamid·pymetrozine WG?2?3?had a better control effect at the later stage in each root-irrigation treatment.3.toxicity test for nontarget organismsAccording to the results of the earthworms acute toxicity test and the earthworms acute toxicity grade criterion of pesticides by LC₅₀0 from GB/T 31270.15-2014"Test guidelines on environmental safety assessment for chemical pesticides",the three preparations and two single-agents are low toxicity.Based on the results of the honeybees acute contact and acute oral toxicity test and the honeybees acute exposure and acute oral toxicity grade criterion of pesticides by LD₅₀0 from GB/T 31270.10-2014"Test guidelines on environmental safety assessment for chemical pesticides",the acute exposure toxicity of 50%flonicamid·pymetrozine WG to honeybees was moderate toxicity,and the others'acute exposure toxicity was low toxicity.The mixtures of flonicamid and pymetrozine exhibited a certain degree of acute contact toxicity to honeybees,but the acute exposure toxicity to honeybees among the three mixtures showed a certain degree of difference.The acute oral toxicity of 50%flonicamid·pymetrozine WG?1?1?was high toxicity,10%flonicamid WG was low toxicity,and the others'acute oral toxicity was moderate toxicity.The acute oral toxicity to honeybees among the three mixtures also showed a certain degree of difference.However,during the test,it was found that 10%flonicamid WG or the difference in auxiliary agent made it have a certain antifeedant action to honeybees,which may be one of the reasons for its low toxicity.Judging from the toxicity to two non-target organisms,the three mixtures will not cause harmful effects on earthworms when used in the prescribed dose.However,it should be used with caution when spraying in the greenhouse of vegetable pollinated by honeybees,especially50%flonicamid·pymetrozine WG?1?1?.Although it showed good performance in control effect,it was highly toxic to honeybees.Three mixtures could be used within the prescribed dose,if there was no bee pollination in the greenhouse.