Toxic Action Of Four Formulations Of Nitenpyram To Two Aquatic Organisms And Nilaparvata Lugens

Nitenpyram is a new neonicotinoid insecticide developed after imidacloprid and Acetamiprid to replace high-toxic organic phosphorus pesticide.Its insecticidal mechanism is different from traditional insecticide.It has the nerve blocking effect against pests.Nitenpyram can be widely used to prevent and wipe out the pests in paddy rice,vegetable,fruit tree,tea and other crops.It possesses good properties of a super-effective,broad-spectrum insecticidal,unique mode of action,low toxicity,systemic,and showing no mutual anti-effect.It has a good development prospect.In the present paper,choose the Nitenpyram:50%Nitenpyram soluble powder,10%Nitenpyram soluble concentrate,20%Nitenpyram water dispersible granule,10%Nitenpyram aqueous solutions and 97%Nitenpyram original medicine.There were a comprehensive comparison study on the acute toxicity of Daphnia Magna srtuas and Brachydanio rerio,the toxicity of the 3rd-larvae of Nilaparvata lugens,and the field efficacy of Nilaparvata lugens.1.A method for the determination of nitenpyram by high performance liquid chromatography has been established.The operating conditions by HPLC were ZORBAX SB-C₁₈8 column,using methanol and water?30:70,by vol?as mobile phase and wavelength215nm.The linear equation was y=55.626x+0.4808,R²=0.9997,the recoveries were88.53%⁹5.64%.The detection method can be used to analyze the concentration of Nitenpyram in the test solution.2.According to Experimental guideline for environmental safety evaluation of chemical pesticides and OECD guidelines for the testing of chemicals,taking Daphnia manga srtuas as tested objects,testing the acute toxicity of Nitenpyram.The results indicated that the48h-EC₅₀0 of 97%Nitenpyram TC was 87.041 mg a.i./L,50%Nitenpyram soluble powder was29.476 mg a..i./L,10%Nitenpyram soluble concentrate was 20.816 mg a.i./L,20%Nitenpyram water dispersible granule was 0.929 mg a.i./L and 10%Nitenpyram aqueous solutions was 2.980 mg a.i./L.20%Nitenpyram water dispersible granule belonged to high toxicity grade,10%Nitenpyram aqueous solutions belonged to middle toxicity grade and the others belonged to slight toxicity grade.3.Semi-static test was used to test the acute toxicity to Brachydanio rerio in different dosage forms of Nitenpyram.The results indicated that the 96h-LC₅₀0 of 97%Nitenpyram original medicine was 267.607 mg a.i./L,50%Nitenpyram soluble powder was 156.215 mg a.i./L,10%Nitenpyram soluble concentrate was 99.650 mg a.i./L,20%Nitenpyram water dispersible granule was 75.808 mg a.i./L and 10%Nitenpyram aqueous solutions was 80.730mg a.i./L.The test agents belonged to slight toxicity grade.Nitenpyram is consistent with the acute toxicity of Daphnia manga srtuas and Brachydanio rerio,20%Nitenpyram water dispersible granule>10%Nitenpyram aqueous solutions>10%Nitenpyram soluble concentrate>50%Nitenpyram soluble powder>97%Nitenpyram original medicine.20%Nitenpyram water dispersible granule and 10%Nitenpyram aqueous solutions are all contain emulsifier K12,resulting in 20%Nitenpyram water dispersible granule and 10%Nitenpyram aqueous solutions High toxicity4.Rice stem dipping method was used to detect the indoor toxicity measurement of Nitenpyram to the third of Nilaparvata lugens.The results showed that the 120h-LC₅₀0 of 50%Nitenpyram soluble powder was 2.608mg/L,10%Nitenpyram soluble concentrate was2.950mg/L,20%Nitenpyram water dispersible granule was 5.465mg/L,and 10%Nitenpyram aqueous solutions was 4.222mg/L.All test agent had higher toxic killing effect on the third age of Nilaparvata lugens.The descending order of the indoor toxicity measurement to the third age of Nilaparvata lugens of these four test agents are as follow,50%Nitenpyram soluble powder>10%Nitenpyram soluble concentrate>10%Nitenpyram aqueous solutions>20%Nitenpyram water dispersible granule.5.Field efficacy test of different dosage forms of Nitenpyram to controlIn Nilaparvata lugens.The results showed that the control effect after 3days was all lower than 70%.After 7days of application,the treatment effect of each treatment was significantly improved.50%Nitenpyram soluble powder and 10%Nitenpyram soluble concentrate were more effective,the average control effect is between 73.72%and 88.28%.20%Nitenpyram water dispersible granule and 10%Nitenpyram aqueous solutions were lower control effect,the average control effect is between 58.69%and 71.02%.On the 10th day after application,the treatment effects of each treatment were improved to some extent.50%Nitenpyram soluble powder in the dosage of 90g/hm2was the highest,up to 91.97%.20%Nitenpyram water dispersible granule in the dosage of 30g/hm2had the lowest effect,but also reached 77.23%.In the trial of lab toxicity and field efficacy of Nilaparvata lugens,50%Nitenpyram soluble powder and 10%Nitenpyram soluble concentrate are more effective.They were all containing penetrant azone,which could make nitenpyram wss easy penetrating into inner of rice leaf.6.According to the ratio of the EC₅₀0 of acute toxicity to Daphnia manga and the LC₅₀0 of the toxicity measurement to Nilaparvata lugens,50%Nitenpyram soluble powder had less toxicity and better efficacy.So the formulation of soluble powder was recommend in control of brown planthopper by nitenpyram in paddy field.