Bait spray for control of European cherry fruit fly: an appraisal based on semi-field and field studies

BACKGROUNDThe European cherry fruit fly, Rhagoletiscerasi, is the major insect pest of sweet and tart cherries. Its management is becoming increasingly difficult in many countries as formerly effective but broad-spectrum insecticides are removed from the market. With the objective of identifying suitable and environmentally safe alternatives, we investigated bait sprays containing two families of plant-derived insecticides: azadirachtins (NeemAzal-T-(R) and NeemAzal-T/S-(R)) and pyrethrins (Spruzit Neu((R))). RESULTSIn 12 semi-field trials conducted within cages, weekly applications of 0.0001 or 0.0005% neem in a bait formulation effectively reduced fruit infestation. However, addition of 0.000125-0.001% pyrethrins did not improve the efficacy of the neem formulations, and when used alone pyrethrins were less effective than neem alone. Two years of field trials were also conducted within orchards wherein an insecticidal barrier of treated trees excluded immigration of fertile R.cerasi from elsewhere. In blocks treated with 0.0005% neem in a bait formulation, we observed 94% (2011) or 86% (2012) reduction of fruit infestation over control blocks. CONCLUSIONBait sprays containing neem are a promising alternative for the management of R.cerasi, especially where the risk of immigration of fertilized females is low, as in isolated orchards or as part of area-wide treatments. (c) 2013 Society of Chemical Industry