Control of sawflies in apple and pear in Belgium

In the Belgian fruit growing area, sawflies are generally common but minor pests in pome fruit. Though, intensity and frequency of sawfly damage in apple and pear is increasing the last years in IPM and especially in organic orchards. The main species are apple sawfly (Hoplocampa testudinea Klug) and pear sawfly (Hoplocaompa brevis Klug) and recently also pear shoot sawfly (Janus compressus Fabricius). Here we report efficacy results on all three sawfly species fromtrial of three consecutive years (2011, 2012, and 2013). Flights and embryonic development were monitored and small plot efficacy trials were executed. Control of apple sawfly was complete (97.6% Abbott -trial 2011) when thiacloprid at 120 g/ha LWA was applied at the moment embryos are visible in the sawfly eggs. In 2012, a trial was executed on pear sawfly. Applications with thiacloprid were executed when the embryo was visible in the pear sawfly eggs and earlier at the start of egg laying. At both application timings, 100% Abbott efficacy was reached. A number of other active ingredients were tested at the moment embryos are visible in the sawfly eggs and very interesting efficacy results were reached for thiofanate-methyl, indoxacarb, spinosad, pyrethrins + piperonyl butoxide (PBO) and acetamiprid. In 2013, a preflowering application with pyrethrins + PBO reached the highest control against this pest. The most effective active ingredients of the pear sawfly trial were applied also in a trial on pear shoot sawfly. Efficacies were low or lacking, except for thiacloprid. Thiacloprid is in pear growing in Belgium only registered before flowering and after harvest. Therefore further research is needed to test the effect of earlier applications against this pest. This is a valuable efficacy study on occasionally occurring pests that are able to cause considerable economic losses.