Thrips control in strawberries – comparison of different IPM strategies

Abstract: Trials were conducted over two years (2008 & 2009) to assess the feasibility of IPMstrategies used in the UK in South West of France tunnel grown strawberries, focusing on thripscontrol, a pest which can lead to major crop losses and has become resistant to most chemicals.Two strategies including Orius laevigatus and Amblyseius cucumeris or Amblyseius swirskiiwere experienced. Moreover the A. cucumeris block was equipped with a misting system in 2008only. Both strategies gave high quality fruits in 2008 and 2009 and kept thrips levels under thecommercial threshold during the whole cropping period. In 2009 (no misting system in bothtunnels), Amblyseius swirskii, established quicker and in higher numbers than A. cucumeris andhelped reducing the thrips larvae numbers per flower, until Orius laevigatus population was highenough to ensure a good thrips control. Adjusted numbers of species introduced, timing and ratesof applications showed that it was possible to reduce the cost of thrips control from 0.66 €/m² forthe strategy including Amblyseius cucumeris and 0.77€/m² for the programme with Amblyseiusswirskii in 2008 down to respectively 0.14€/m² and 0.17€/m² in 2009, making it possible todevelop cost efficient IPM strategies for strawberry growers.