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Notes:
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The codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), is the key pest on pome fruit and walnut orchards worldwide. Its resistance to available insecticides has been widely reported. Chlorantraniliprole is an anthranilic diamide that was introduced in European countries in 2008-2009 and acts by activating the insect's ryanodine receptors. The aims of this study were to determine the baseline susceptibility of European populations of C. pomonella to chlorantraniliprole, to establish the discriminant concentrations (DC) to check the possible development of resistance, and to know the role of cytochrome P450 monooxygenases (P450) in the possible susceptibility decrease of field populations to the insecticide. Ten field populations from Spain along with others were used to calculate the baseline response of larvae to chlorantraniliprole incorporated into the diet. A pooled probit line was calculated, and three DC were established: 0.3 mg a.i./kg (close to the LC50), 1.0 mg a.i./kg (close to the LC90), and 10 mg a.i./kg diets (threefold the LC99). The DC were used to test the susceptibility of 27 field populations from France, Germany, Hungary, Italy, and Spain. The corrected mortality observed in all cases ranged within the expected interval, even with Spanish populations that showed between 12.1 and 100.0% of individuals with high P450 activity. However, the mortality caused by the DC0.3 decreased as the mean P450 activity increased. Field populations resistant to other insecticides were susceptible to chlorantraniliprole. The determined baseline codling moth susceptibility is a valuable reference for tracking possible future alterations in the efficacy of the insecticide.
The authors would like to express their sincere thanks to the fruit growers and to the
grower advisors of the differe
nt areas (ADV technicians) who he
lped identify the best orchards for the assay, to the collectors of the field populati
ons in the different countries
and to Mònica Pérez for her tec
hnical help. Special thanks to J
. L. Rison, M. O. Haxaire
and S. Pasquini, from DuPont, for their helpful comments on the
manuscript.
This study
was funded by DuPont and partially supported by grants AGL2013-49164 and AGL2016-
77373 of the Spanish Ministry for Science and Innovation and by
the CERCA Programme
/ Generalitat de Catalunya. |
