Helicoverpa armigera has been controlled effectively with chemical insec- ticides in the major cotton crop production areas of northern Greece for many years. However, a resurgence of the pest was observed in 2010, wh...Helicoverpa armigera has been controlled effectively with chemical insec- ticides in the major cotton crop production areas of northern Greece for many years. However, a resurgence of the pest was observed in 2010, which significantly affected crop production. During a 4-year survey （2007-2010）, we examined the insecticide re- sistance status of 1-1. armigera populations from two major and representative cotton production areas in northern Greece against seven insecticides （chlorpyrifos, diazinon, methomyl, alpha-cypermethrin, cypermethrin, gamma-cyhalothrin and endosulfan）. Full dose-response bioassays on third instar larvae were performed by topical application. Lethal doses at 50% were estimated by probit analysis and resistance factors （RF） were calculated, compared to a susceptible laboratory reference stra^a. Resistance levels were relatively moderate until 2009, with resistance ratios below 10-fold for organophosphates and carbamates and up to 16-fold for the pyrethroid alpha-cypermethrin. However, resis- tance rose to 46- and 81-fold for chlorpyrifos and alpha-cypermethrin, respectively in 2010, when the resurgence of the pest was observed. None of the known pyrethroid resistance mutations were found in the pyrethroid-resistant insects. The possible association between resistance and H. armigera resurgence in Greece is discussed.展开更多
文摘Helicoverpa armigera has been controlled effectively with chemical insec- ticides in the major cotton crop production areas of northern Greece for many years. However, a resurgence of the pest was observed in 2010, which significantly affected crop production. During a 4-year survey （2007-2010）, we examined the insecticide re- sistance status of 1-1. armigera populations from two major and representative cotton production areas in northern Greece against seven insecticides （chlorpyrifos, diazinon, methomyl, alpha-cypermethrin, cypermethrin, gamma-cyhalothrin and endosulfan）. Full dose-response bioassays on third instar larvae were performed by topical application. Lethal doses at 50% were estimated by probit analysis and resistance factors （RF） were calculated, compared to a susceptible laboratory reference stra^a. Resistance levels were relatively moderate until 2009, with resistance ratios below 10-fold for organophosphates and carbamates and up to 16-fold for the pyrethroid alpha-cypermethrin. However, resis- tance rose to 46- and 81-fold for chlorpyrifos and alpha-cypermethrin, respectively in 2010, when the resurgence of the pest was observed. None of the known pyrethroid resistance mutations were found in the pyrethroid-resistant insects. The possible association between resistance and H. armigera resurgence in Greece is discussed.
