title: Resurgence of the cotton bollworm Helicoverpa armigera in northern Greece associated with insecticide resistance.
abstract: Helicoverpa armigera has been controlled effectively with chemical insecticides 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 resistance status of H. 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 strain. 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, resistance 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.
authors: Laboratory of Applied Zoology and Parasitology, Faculty of Agriculture, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors: George K
authors: GK
authors: Mironidis
authors: Despina
authors: D
authors: Kapantaidaki
authors: Maria
authors: M
authors: Bentila
authors: Evangelia
authors: E
authors: Morou
authors: M
authors: M
authors: Savopoulou-Soultani
authors: John
authors: J
authors: Vontas
mesh_terms: D000818:Animals; D004390:Chlorpyrifos / Q000494:pharmacology; D004726:Endosulfan / Q000494:pharmacology; D003368:Gossypium / Q000469:parasitology*; D006115:Greece; D007305:Insecticide Resistance; D007306:Insecticides / Q000494:pharmacology*; D009036:Moths / Q000187:drug effects* / Q000502:physiology; D009570:Nitriles / Q000494:pharmacology; D010935:Plant Diseases / Q000469:parasitology*; D011722:Pyrethrins / Q000494:pharmacology
chemical_list: D007306:Insecticides; D009570:Nitriles; D011722:Pyrethrins; C017160:cypermethrin; D004390:Chlorpyrifos; D004726:Endosulfan; C037304:cyhalothrin
keywords: bioassay; carbamates; cotton field; endosulfan; organophospates; pyrethroids