Comparative evaluation of insecticides in control of Bothynoderes punctiventris Germ. under laboratory and field conditions

Abstract

Beet weevil (Bothynoderes punctiventris Germ.) is the most damaging pest of sugar beet in south-eastern Europe, from seedling emergence and in the first phases of crop development. Efficacy of insecticides (active ingredients of chlorpyriphos + bifenthrin, chlorpyriphos + beta-cyfluthrin and chlorpyriphos + cypermethrin) for the control of beet weevil was tested during 2010 and 2011 under laboratory and field conditions. A wet filter paper method (contact action) was employed in laboratory tests. Simultaneously, field trials were conducted (Čurug, Rimski Šančevi, Budisava, Kovilj) (contact and digestive action). The trial was designed according to EPPO method and insecticide efficacy was tested in accordance with the pest biology and phenophase of the crop. Insecticide efficacy was calculated using Abbot's formula, and damage of plants was assessed using 0-5 scale. Commercial insecticide Nurelle D (active ingredient of chlorpyriphos + cypermethrin) maintained high contact and digestive action on beet weevil, although it has been in use for 20 years. Commercial insecticide Pyrinex Super (active ingredient of chlorpyriphos + bifenthrin), although with reduced content of chlorpyriphos by 30% and of bifenthrin by 20%, achieved efficacy that was at the same level of significance with Nurelle-D, regardless of the experimental conditions (laboratory or field). Compared to Nurelle-D, the product MCW 784 (chlorpyriphos + beta-cyfluthrin) had significantly lower initial efficacy 3 h after application in laboratory trial, and also 24 h after application in field trial.