Changes in Meligethesaeneus (Coleoptera: Nitidulidae) susceptibility to lambda-cyhalothrin in the Czech Republic between 2009 and 2011

Abstract

Susceptibility of Meligethes sp. (mainly M. aeneus) from the Czech Republic was tested with lambda-cyhalothrin (111 samples in 2009, 125 in 2010, and 102 in 2011) through the use of IRAC method No. 011, Vers. 3. Resistant samples were the most frequent in all three years and their proportions increased from 33% to 62% between 2009 and 2011. The last samples classified as highly susceptible were recorded in 2010. The mean percentage mortalities for a common European field rate of 7.5 g a.i/ha were 82.2% in 2009, 78.92% in 2010, and 67.45% in 2011(according to Abbott's formula). The values of LC50 ranged from 0.084 to 47.27 g a.i./ha in 2009, from 0.051 to 46.78 g a.i./ha in 2010, and from 0.238 to 19.92 g a.i./ha in 2011. Only in 17.65% of samples there were LC90 values below the European field rate in 2011.

Keywords

• pollen beetles
• pyrethroid resistance
• esteric pyrthroids
• adult vial tests
• irac