Negative correlations between the susceptibilities of Czech and Slovak pollen beetle populations to lambda-cyhalothrin and chlorpyrifos-ethyl in 2014 and 2015

Abstract

Sixty-five Czech Meligethes populations were tested against lambda-cyhalothrin and chlorpyrifos-ethyl in 2014. In 2015, totally sixty Meligethes populations, some of which sampled also in Slovakia, were tested against the two insecticides. Adult vial tests by IRAC (Insecticide Resistance Action Committee) were used for testing (No. 011 v. 3 for lambda-cyhalothrin and No. 025 for chlorpyrifos-ethyl). For each of the tested populations the LC50, LC90, and in 2015 also LC95 values were determined for both these insecticides. Correlation analyses were made with transformed (log10 transformation) LC values. No significant correlation was recorded between the LC50 values. Contrary to that, significant (P < 0.05) negative (r values for negative) correlations were recorded between the LC90 and LC95 values. Pyrethroid resistance in pollen beetle populations should indicate their slightly higher susceptibility to chlorpyrifos-ethyl.

Keywords

• meligethes aeneus
• pyrethroid resistance
• susceptibility to organophosphates
• irac adult vial tests