Toxicity Assessment Of Three Types Of Insecticides To Bombus Terrestris And Efficacy Evaluation Of B.terrestris For Utilizing As Pollination Agents

Bumblebees are one of the most important pollinating insects in nature,and they are also economic insects that have developed rapidly in recent years.As the most mature commercial type of bumblebee species,Bombus terressit has attracted widespread attention in the world.However,the heavy use of pesticides has greatly affected pollinating insects such as bumblebees.In order to protect Bombus terressit better,improve the safety of insecticide use,and reduce the impact of chemical pesticides on Bombus terressit,this study selected three major types of insecticides including neonicotinoid,insecticides botanical insecticides,and insect growth regulators insecticides.The acute toxicity and risk of these three types of insecticides to ground bumblebee worker bees were evaluated.Based on the obtained results,the most representative types of pesticides were screened out,and field experiments were conducted to examine the toxic effects on bumblebees in the greenhouse conditions,with a view to the rational use of pesticides in the facilities and the development of Bombus terressit protection provides a theoretical basis,while conducting pollination field tests and analysis of indoor biochemical indicators to verify the advantages of Bombus terressit pollination.The main research results are as follows:1.The acute toxicity and risk assessment of thiamethoxam and other seven neonicotinoid insecticides to workers of Bombus terressit were measured.The results showed that among the eight neonicotinoid insecticides,the oral and contact toxicity of acetamiprid,thiacloprid and flupurone are low;the oral and contact toxicity of thiamethoxam,clothianidin,imidacloprid,nitenpyram and dinotefuran are high.Ecological risk assessment showed that acetamiprid,thiacloprid and flupirfenone showed low risk to adult workers of B.terrestris,while imidacloprid,nitenpyram and dinotefuran showed moderate risk.Thiamethoxam and clothianidin showed moderate risk to adult workers of B.terrestris in oral toxicity,while high risk in contact toxicity.2.The acute toxicity and risk assessment of matrine and other five neonicotinoid botanical insecticides to workers of Bombus terressit were measured.The results show that among the selected six botanical insecticides,the oral and contact toxicity of pyrethrin is low toxicity,and the risk assessment is low risk;both cucurbitine and celangulinare highly toxic,and the risk assessment is moderate in oral transit and low in exposure;the oral toxicity of ostholeispoisoning,the exposure toxicity was high,and the risk assessment is low;the oral toxicity of matrine and rotenone is poisoning and exposure is low,and the risk assessment is low.3.The acute toxicity and risk assessment of hexaflumuron and other five neonicotinoid insecticides to workers of Bombus terressit were measured.The results show that the oral and contact toxicity of the seven insect growth regulator insecticides was low,and the risk assessments were low risk.Among them,pyriproxyfen,buprofezin,and chlorpromil have reached the limit of the toxicity test,that is,there was no death of ground bumblebee when the test substance was 200 ug a.i./ bee.4.The results of the evaluation of the toxicity of three selected insecticides on bumblebees in the facility conditions showed that the number of dead worker bees in the shed was compared with the control group,and there was no significant difference between the three selected insecticides on the 1st and 7th days after treatment.The pollination rate,the number of collisions,and the flight intensity were significantly different from the control group as a whole between 1-7 days after the treatment,and the number of collisions was most significant with acetamiprid.5.The results of the measurement of living material indexes of different pollination methods showed that the total sugar in the six-ear bumblebee pollination group increased by 32.29% and 59.47%,and the glycolic acid ratio increased by 75.49% and 101.01%,respectively,and the glycolic acid ratio increased by 63.58% in the five-ear bumblebee pollination group compared with the five-ear vibration pollination group.The total sugar,glycolic acid ratio and titratable acid ratio in bumblebee pollination group were increased by 18%,57.61% and 24.81% respectively.Compared with the non-pollinated group,bumblebee group could titrate 44.51% more circle pepper and 26.19% less glycolic acid,while horn pepper could titrate 44.51% more acid and 26.19% less glycolic acid,while horn pepper could titrate 32.35% more acid.Compared with the non-pollinated group,the glycolic acid ratio increased by 44.7%.Compared with the hormone spot group,the total sugar of melo bumblebee pollination group increased by 68.96%,titrable acid decreased by 42.86%,sugaracid ratio increased by 194.74%,VC of amur horn honey increased by 53.64%,sugar-acid ratio increased by 37.7%.All the results above indicate that the greenhouse crops pollinated by bumblebee have higher quality and better flavor.6.A feasible solution for using bumblebees to simultaneously apply insecticides when pollinating crops in a facility environment is to follow the principles of green environmental protection and prioritize the use of pesticides in the order: insect growth regulator insecticides and botanical insecticides > neonicotinoid insecticides The low-toxic and low-risk agent is selected to prevent corresponding pests.At the same time,it is best to put ground bumblebees to pollinate 2 days after low-toxicity pesticide to reduce the damage to ground bumblebees.Prolong the pollination time and observe the Bombus terressit population dynamics in time.To prevent some agents from causing harm to larvae and affecting normal pollination.