Efficacy of chlotianidyna (neonicotinoid group) in the control of the strawberry root weevil (Otiorhynchus ovatus) on strawberry

Abstract: The strawberry root weevil (Otiorhynchus ovatus) feeds on roots and, therefore, it is a very dangerous pest on older strawberry plantations. The efficacy of two clothianidine formulations (Apacz 50 WG (clothianidine 50%) and TI 435 1 GR (CAGR 8; Santana 1 GR) (clothianidine)) were tested against the strawberry root weevil on strawberry plantations. Both insecticides belong to neonicotinoid group. Granular formulation (TI 435 1GR) incorporated into soil at the rate of 10 and 15kg/ha in the spring, before strawberry blossom, reduced significantly the number of weevil larvae. In two trials TI 435 1 GR applied at the higher rate (15kg/ha) decreased the number of larvae by 72%. The efficacy of this insecticide used at the lower rate (10kg/ha) against weevil larvae was 61.3 and 78.7%. Results obtained with TI 435 1 GR were similar to those obtained with standard insecticide – Diazinon 10 GR (80kg/ha). Apacz 50 WG applied as a spray treatment at the rate of 0.15 and 0.20kg/ha before strawberry blossom reduced weevil larvae by 74.5-99.6%. Apacz 50 WG applied at the rate of 0.15 and 0.20kg/ha just after strawberry harvest reduced the pest abundance by 72.1-96.3%. Reduction of the pest at this time is very important because after harvest adults of the strawberry root weevil feed on leaves and females lay eggs. The results obtained with Apacz 50 WG were similar or better than those obtained with standard the insecticides; Diazinon 10 GR or Dursban 480 EC (chlorpyrifos).