Targeted application to the basal part of trunk to control the woolly apple aphid (Eriosoma lanigerum)

In recent years, the presence of the woolly apple aphid (Eriosoma lanigerum) has increased in apple orchards in both integrated production and organic farming. Possible reasons include reduction in organophosphate insecticide use, negative side effect of pesticides on natural enemies and increased overwintering survival. As a result of the aphid's feeding stings, tumours and knots appear on young branches and on old wood. This results in a general weakening of the plant, which is more susceptible to other plant diseases and attacks by other pests. In addition, the emission of honeydew can sully the fruit, compromising its aesthetic characteristics. Part of the biological cycle of the insect is carried out at root level with the crawler moving up the trunk in spring to colonise the plant. Localised application at the trunk can therefore be an effective strategy to contain the insect populations and allows rationalisation of the doses used. In field tests, three equipment were compared to preliminarily check tracer mixture deposits on the trunk: an axial sprayer with air injection nozzles, a hand lance with triple jet, a spray boom with mechanical sensor. The equipment that performed better in terms of deposition efficiency were consequently used in full field trials. The efficacy was compared for one or two applications with mineral oil (Polithiol). The equipment with intermittent jet opening (boom) allowed a high level of efficacy and a reduction in the use of the plant protection product. The possibility to reduce the use of PPP even by using basic sensing technologies is shown by this work. Therefore, the adoption of precision spraying technologies recently developed could hugely increase the sustainability of treatments in near future.