The resistance to several insecticides and IGR's and the interaction of
insecticide I IGR mixtures were evaluated in Gharbia field strain of the cotton
leafworm Spodoptera littoralis (Blosd.) before and after insecticidal application in 2000
cotton season. The results revealed that the field strain was very highly resistant to the
pyrethroid Surnl-alpha and sumicidin, however low to moderate levels of resistance
were recorded to the pyrethroid, Meothrin; organophosphates and carbamates tested
were found, except lannate which had resistance ratio surpassed the critical level.
Regarding level of resistance to IGR's at 5 days after treatment, results showed that S, Httoraiis was highly susceptible to the toxic action of Cascade and Mimic. No detectable levels of resistance to Atabron, Match and Consult were observed before control season, but resistance to Atabron and Match increased to 4.3 and 5.2-fold, respectively after control season-Low level of resistance to Alsystin was detected. However, high level of resistance, but still bellow the critical limit of resistance to Phares was found.The jOint action of Oursban,lIGR and curacron IIGR combinations revealed that Dursban potentiated most of IGR s in susceptible and field strains before and after control season, while Curacron potentiated Cascade, Match and Mimic in susceptible strain; Cascade and Match in fl8ld strain before control season and only Consult after oontrol season.
The resistance to several insecticides and IGR's and the interaction of
insecticide I IGR mixtures were evaluated in Gharbia field strain of the cotton
leafworm Spodoptera littoralis (Blosd.) before and after insecticidal application in 2000
cotton season. The results revealed that the field strain was very highly resistant to the
pyrethroid Surnl-alpha and sumicidin, however low to moderate levels of resistance
were recorded to the pyrethroid, Meothrin; organophosphates and carbamates tested
were found, except lannate which had resistance ratio surpassed the critical level.
Regarding level of resistance to IGR's at 5 days after treatment, results showed that S, Httoraiis was highly susceptible to the toxic action of Cascade and Mimic. No detectable levels of resistance to Atabron, Match and Consult were observed before control season, but resistance to Atabron and Match increased to 4.3 and 5.2-fold, respectively after control season-Low level of resistance to Alsystin was detected. However, high level of resistance, but still bellow the critical limit of resistance to Phares was found.The jOint action of Oursban,lIGR and curacron IIGR combinations revealed that Dursban potentiated most of IGR s in susceptible and field strains before and after control season, while Curacron potentiated Cascade, Match and Mimic in susceptible strain; Cascade and Match in fl8ld strain before control season and only Consult after oontrol season.
INTRODUCTION