Differential susceptibility to insecticides by Leptinotarsa decemlineata [Coleoptera: Chrysomelidae] populations from western Canada

Abstract

La sensibilité du doryphore de la pomme de terre (Leptinotarsa decemlineata) de trois provinces de l’Ouest canadien a été mesurée par bioessai sur papier filtre pour corroborer les comptes rendus faisant état de doryphores résistants aux insecticides au Manitoba, et pour comparer la situation au Manitoba à celles de la Saskatchewan et de l’Alberta. La sensibilité des doryphores a été mesurée pour cinq insecticides : les organophosphates azinphos-méthyl (Guthion) et méthamidophos (Monitor), le pyréthroïde perméthrine (Ambush), l’organochloré endosulfan (Endosulfan) et le carbamate carbaryl (Sevin). Les 12 populations du Manitoba examinées démontraient de la résistance à au moins un des insecticides. Toutes les populations ont été classées comme étant résistantes ou moyennement résistantes à la perméthrine; deux des populations ont été classées comme résistantes à l’azinphos-méthyl et trois au méthamidophos. Deux des quatre populations de la Saskatchewan ont été classées comme étant moyennement résistantes à l’azinphos-méthyl et au méthamidophos. Une résistance intermédiaire à la perméthrine a été trouvée dans 12 des 13 populations de l’Alberta, alors qu’une seule était très sensible. Deux populations se sont montrées moyennement résistantes à l’azinphos-méthyl et trois au méthamidophos. Dans les trois provinces, le taux de survie de diverses masses d’oeufs provenant de populations sensibles variait de 0 à 100 %, ce qui montre que des individus résistants, moyennement résistants et très sensibles coexistent dans ces populations. Avec l’expansion de la culture de la pomme de terre dans l’Ouest canadien et la détection d’une résistance aux insecticides dans les populations du doryphore de la pomme de terre, un programme de gestion de la résistance doit être mis en place pour éviter la sélection rapide de populations résistantes.The susceptibility of Colorado potato beetles (Leptinotarsa decemlineata) (CPB) from three provinces in western Canada was measured using a filter paper bioassay to substantiate the reported insecticide resistance by the beetle in Manitoba, and to compare the situation there to beetle populations from Saskatchewan and Alberta. Susceptibility of beetles was measured against five insecticides: the organophosphates, azinphos-methyl (Guthion), and methamidophos (Monitor); the pyrethroid, permethrin (Ambush); the organochlorine, endosulfan (Endosulfan); and the carbamate, carbaryl (Sevin). All 12 populations tested from Manitoba were found to have resistance to one or more of the insecticides. All populations were classified as either having resistance or intermediate resistance to permethrin; two of the populations were classified as having resistance to azinphos-methyl and three to methamidophos. Two of four populations from Saskatchewan were classified as having intermediate resistance to azinphos-methyl and methamidophos. Intermediate resistance to permethrin was recorded in 12 of the 13 populations from Alberta, with only one being highly susceptible. Two populations showed evidence of interme...

Damage potential and phenology of the Colorado potato beetle [Coleoptera: Chrysomelidae] on potato in southern Alberta

“…With the presently expanding potato industry, an increase in the CPB population could resuit in the need for increased insecticide applications and the possible rapid development of résistance. The large numbers of beetles already demonstrating lower susceptibility to insecticides in southern Alberta are an indication that résistant populations are being selected (Noronha et al 2001). Our results indicate that the phenology of CPB is similar to that reported in areas where population buildups were rapid and devastating, soon after insecticide résistant populations appeared.…”

“…In eastern Canada, loss of control efficacy due to résistance to ail four chemical classes of insecticides resulted in the emergency registration of imidacloprid (Admire™ 240F), an insecticide with a new mode of action. In western Canada, there hâve been récent reports of insecticide résistance from Manitoba (Gavloski 1997;Noronha et al 2001). In Alberta, tested CPB populations remain susceptible to cheaper conventional insecticides (Noronha et al 2001), making the cost of CPB control more economical relative to areas that must apply more expensive, newerchemical insecticides.…”

“…In western Canada, there hâve been récent reports of insecticide résistance from Manitoba (Gavloski 1997;Noronha et al 2001). In Alberta, tested CPB populations remain susceptible to cheaper conventional insecticides (Noronha et al 2001), making the cost of CPB control more economical relative to areas that must apply more expensive, newerchemical insecticides. However, little is known about the phenology and damage potential of CPB in Alberta.…”

Colorado Potato Beetle Resistance to Insecticides

“…In subsequent years, failures have been reported for most major classes of insecticides (Table 2). Although the northeastern United States is one of the main problem areas (Forgash 1985;Whalon and Ferro 1998), insecticide resistance in the Colorado potato beetle is a truly global phenomenon (Hofmaster et al 1967;Forgash 1985;Boiteau 1988b;Ioannidis et al 1991;Heim et al 1992;Stewart et al 1997;Noronha et al 2001;Stankovic et al 2004;Pourmirza 2005;Mota-Sanchez et al 2006;Benkovskaya et al 2006;Mohammadi Sharif et al 2007;Whalon et al 2008). Obviously, not every beetle population is resistant to every single compound that has ever been observed to fail against this pest.…”

Resistance Potential of Colorado Potato Beetle (Coleoptera: Chrysomelidae) to Novaluron

“…Tolman et al (2003) found that in the majority of cases, these same populations exhibited reduced susceptibility to imidacloprid, lambda-cyhalothrin, spinosad, and azinphos-methyl, suggesting mechanisms that reduced susceptibility to these compounds also may have resulted in reduced susceptibility to novaluron. In a survey of susceptibility of Colorado potato beetle populations from western provinces, Noronha et al (2002) also found high prevalence of insecticide resistance in Manitoba populations. They attributed this to extensive insecticide use to control growing Colorado potato beetle populations that followed a rapid increase in potato acreage in Manitoba in the 1990s.…”