Control Effect Of Insecticides And The Synergistic Effect Of Synergists Against Bemisia Tabaci

The control effects of different pesticides against Bemisia tabaci MED cryptic species were studied.And the synergistic effects of four synergists on controlling Bemisia tabaci MED cryptic species by cyantraniliprole and sulfoxaflor were discussed.The main results are as follows:1.Field efficacy and pesticide residue detection of 8 different pesticides against Bemisia tabaci MED cryptic species were tested in greenhouse of cucumber and eggplant,respectively.Results showed that the control effect of eight insecticides is in the range of 78.98%～96.66%on cucumber after the application of10 d,and it is around 39.59%～81.11%on eggplant.The highest effects on cucumber and eggplant was obtained in treatments of cyantraniliprole 10%OD and sulfoxaflor 50%WG after the application of 10 d.Effects of both insecticides were 94.90%and 94.18%in greenhouse of cucumber,respectively.Where as75.24%and 81.11%effects were obtained in the greenhouse of eggplant,respectively.Effects of three Neonicotinoid insecticides against Bemisia tabaci MED cryptic species on cucumber and eggplant were at78.98%～89.22%and 60.58%～79.09%,respectively.Methoxyfenozide 240 g/L SC showed 80.79%and80.41%efficiencies to Bemisia tabaci MED cryptic species on both crops of cucumber and eggplant.The treatment of cyantraniliprole 10%OD combined with ethoxy modified trisiloxane showed 1.86%～67.40%increasing than that of single treatment of pesticide.2.At the recommended dosage,there were 0.52 mg/kg and 2.06 mg/kg of residues were detected in cucumber stem and leaf from treatments of thiamethoxam and acetamiprid,and 0.03 mg/kg,2.36 mg/kg and 4.75 mg/kg were detected in eggplant stem and leaf from treatments of abamectins,pymetrozine and methoxyfenozide,the amount of residues are all over the national standard of fruit MRLs.However none of residue was detected in cucumber fruit for all of tested insecticides treatment after the application of 15 d(<0.01 mg/kg).3.The effects of four synergists,Yi Ou,Jin Nuo,Ji Jian and Jie Xiao-li,on the physical properties of two pesticides,cyantraniliprole and sulfoxaflor,were determined in laboratory.Results show that the addition of synergist could significantly reduce the surface tension of the liquid,and the most significant effect was Jie Xiao-li.The surface tension of cyantraniliprole and sulfoxaflor liquid accounted for 7.48m N/m and 6.83 m N/m,respectively.60.90%and 69.48%lower than the control,and it could quickly spreading on the surface of leaves.The greatest impact on the retention of two liquids on eggplant leaves was Yi Ou,at 1.59 mg/cm~2 and 1.24 mg/cm~2 respectively,an increase of 40%and 20%over the control.4.Sinergistic ratios of synergists,Yi Ou,Jin Nuo,Ji Jian,Jie Xiao-li mixed with cyantraniliprole and sulfoxaflor against Bemisia tabaci MED cryptic species adults were 1.72,1.66,1.50,1.18 and 1.77,1.53,1.37,1.25,respectively;And against nymphs were 1.59,1.44,1.36,1.22 and 1.82,1.71,1.39,1.60.The addition of different synergist can reduce the dosage of 19.70%～60.37%and the toxicity can not be reduced.5.Results of field experiment showed that the synergist Yi Ou could significantly improve the control effect of cyantraniliprole and sulfoxaflor to Bemisia tabaci MED cryptic species.The average control effect was increased by 34.51%and 49.56%compared with that of the recommended dosage alone.The control effect can be maintained over 60%with a significant difference after the application of 10 d.It was confirmed that the addition of synergist Yi Ou could decrease the pesticide amount but increas efficiency.