The whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae) is one of the most devastating agricultural pests in many cropping systems worldwide. Growers rely on the use of insecticides to control this pest. However, some i...The whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae) is one of the most devastating agricultural pests in many cropping systems worldwide. Growers rely on the use of insecticides to control this pest. However, some insecticides do not reduce the feeding of B. tabaci fast enough to prevent the direct and indirect damage produced by this insect. The effect of a new insecticide, cyantraniliprole 10OD (CyazypyrTM), on the feeding of B. tabaci adults, was studied under laboratory conditions. Cyantraniliprole 10OD is an insecticide that belongs to the IRAC Group 28 with a new mode of action for sucking insects, which provides rapid feeding cessation by impairing muscle function, resulting in reduced transmission of important insect vectored crop diseases. Laboratory experiments were conducted to determine the effect of cyantraniliprole along with some other commercially available insecticides on the feeding of B. tabaci adults by measuring the excretion of honeydew as an indirect assessment of insect feeding. In these experiments, cyantraniliprole resulted in significantly higher reduction of honeydew excretion (64.0%) by Q biotype B. tabaci adults during the first 30 minutes of exposure than diafenthiuron, triazophos, acetamiprid and spiromesifen, with all treatments having no adult mortality. Observations between 1 and 48 hours after exposure indicated that cyantraniliprole had numerically higher or similar reduction in honeydew production as the other insecticides, but by 48 hours (mid and high rate) and 96 hours (high rate) of exposure, cyantraniliprole had significantly higher reduction of honeydew excretion than all other insecticides tested. Low adult mortality was observed during first 24 hours of exposure in all treatments. Cyantraniliprole resulted in numerical or significantly higher adult mortality than all other treatments at the later observation intervals (72 - 96 hours). The higher reduction in honeydew excretion by cyantraniliprole appeared to be related to faster feeding cessation during the initial hours of exposure by a combination of feeding cessation and direct mortality as the exposure time increased. These findings document significant effects of cyantraniliprole on feeding cessation in Bemisia tabaci.展开更多
The present study explored the Spilanthes acmella Murr. for insecticidal principle, a plant of high value. The seed extract showed insecticidal activity against Plutella xylostella. Further, bioassay guided isolation ...The present study explored the Spilanthes acmella Murr. for insecticidal principle, a plant of high value. The seed extract showed insecticidal activity against Plutella xylostella. Further, bioassay guided isolation of bioactive compounds resulted in insecticidal active molecule, which was identified with the help of ESI-MS and NMR. Highest activity of 95 - 100 percent was observed at low dose of 2 g/l with spilanthol, while 60 - 70 and 80 - 90 percent mortality at 5 g/l in crude seed extracts prepared in methanol and hexane after 48 hours exposure, respectively. LC50 of 1.49, 5.14, 5.04, 11.75 g/l was observed with spilanthol, crude seed extract of methanol, hexane, deltamethrin, respectively. The findings indicate the potential of S. acmella with potent insecticidal toxicity for the management of P. xylostella and other insects of agricultural importance.展开更多
文摘The whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae) is one of the most devastating agricultural pests in many cropping systems worldwide. Growers rely on the use of insecticides to control this pest. However, some insecticides do not reduce the feeding of B. tabaci fast enough to prevent the direct and indirect damage produced by this insect. The effect of a new insecticide, cyantraniliprole 10OD (CyazypyrTM), on the feeding of B. tabaci adults, was studied under laboratory conditions. Cyantraniliprole 10OD is an insecticide that belongs to the IRAC Group 28 with a new mode of action for sucking insects, which provides rapid feeding cessation by impairing muscle function, resulting in reduced transmission of important insect vectored crop diseases. Laboratory experiments were conducted to determine the effect of cyantraniliprole along with some other commercially available insecticides on the feeding of B. tabaci adults by measuring the excretion of honeydew as an indirect assessment of insect feeding. In these experiments, cyantraniliprole resulted in significantly higher reduction of honeydew excretion (64.0%) by Q biotype B. tabaci adults during the first 30 minutes of exposure than diafenthiuron, triazophos, acetamiprid and spiromesifen, with all treatments having no adult mortality. Observations between 1 and 48 hours after exposure indicated that cyantraniliprole had numerically higher or similar reduction in honeydew production as the other insecticides, but by 48 hours (mid and high rate) and 96 hours (high rate) of exposure, cyantraniliprole had significantly higher reduction of honeydew excretion than all other insecticides tested. Low adult mortality was observed during first 24 hours of exposure in all treatments. Cyantraniliprole resulted in numerical or significantly higher adult mortality than all other treatments at the later observation intervals (72 - 96 hours). The higher reduction in honeydew excretion by cyantraniliprole appeared to be related to faster feeding cessation during the initial hours of exposure by a combination of feeding cessation and direct mortality as the exposure time increased. These findings document significant effects of cyantraniliprole on feeding cessation in Bemisia tabaci.
文摘The present study explored the Spilanthes acmella Murr. for insecticidal principle, a plant of high value. The seed extract showed insecticidal activity against Plutella xylostella. Further, bioassay guided isolation of bioactive compounds resulted in insecticidal active molecule, which was identified with the help of ESI-MS and NMR. Highest activity of 95 - 100 percent was observed at low dose of 2 g/l with spilanthol, while 60 - 70 and 80 - 90 percent mortality at 5 g/l in crude seed extracts prepared in methanol and hexane after 48 hours exposure, respectively. LC50 of 1.49, 5.14, 5.04, 11.75 g/l was observed with spilanthol, crude seed extract of methanol, hexane, deltamethrin, respectively. The findings indicate the potential of S. acmella with potent insecticidal toxicity for the management of P. xylostella and other insects of agricultural importance.
