Honey bees are important pollinators and are essential in agriculture;as such they get exposed to a wide range of pesticides while foraging in contaminated fields or during the spray of chemical on crops. It is theref...Honey bees are important pollinators and are essential in agriculture;as such they get exposed to a wide range of pesticides while foraging in contaminated fields or during the spray of chemical on crops. It is therefore important to know the toxicity and evaluate the impacts of bees’ exposure to these molecules. Acetamiprid and cypermethrin are two pesticides widely used in Cameroon and other countries. The objective of this study was to determine the toxicity of acetamiprid and cypermethrin on the native subspecies of <em>Apis mellifera</em> L. in agricultural areas in Adamaoua-Cameroon and to evaluate the impact on honeybee foragers exposed to lethal and sublethal doses of these two insecticides. The results obtained in laboratory conditions show that acetamiprid and cypermethrin are toxic to <em>A. mellifera</em>. The symptoms of neurotoxicity and first mortality appear 15 min after the ingestion of the high concentrations and about 30 to 45 min after the inoculation of the pesticides through contact route and the mortality increases with the concentration and time. The LC50 of acetamiprid obtained after 24 h are respectively 5.26 ng/μl for the topical application and 4.70 μg/μl by the oral route. At the same time, the LC50 of cypermethrin are respectively 2.27 ng/μl for topical application and 2.68 ng/μl for oral toxicity. For a sustainable agriculture and beekeeping, it is, therefore, important to establish quality measures on these insecticides in the ecosystem and to set up a phyto-pharmacovigilance and awareness system to the population.展开更多
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Honey bees are important pollinators and are essential in agriculture;as such they get exposed to a wide range of pesticides while foraging in contaminated fields or during the spray of chemical on crops. It is therefore important to know the toxicity and evaluate the impacts of bees’ exposure to these molecules. Acetamiprid and cypermethrin are two pesticides widely used in Cameroon and other countries. The objective of this study was to determine the toxicity of acetamiprid and cypermethrin on the native subspecies of <em>Apis mellifera</em> L. in agricultural areas in Adamaoua-Cameroon and to evaluate the impact on honeybee foragers exposed to lethal and sublethal doses of these two insecticides. The results obtained in laboratory conditions show that acetamiprid and cypermethrin are toxic to <em>A. mellifera</em>. The symptoms of neurotoxicity and first mortality appear 15 min after the ingestion of the high concentrations and about 30 to 45 min after the inoculation of the pesticides through contact route and the mortality increases with the concentration and time. The LC50 of acetamiprid obtained after 24 h are respectively 5.26 ng/μl for the topical application and 4.70 μg/μl by the oral route. At the same time, the LC50 of cypermethrin are respectively 2.27 ng/μl for topical application and 2.68 ng/μl for oral toxicity. For a sustainable agriculture and beekeeping, it is, therefore, important to establish quality measures on these insecticides in the ecosystem and to set up a phyto-pharmacovigilance and awareness system to the population.
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.
