Use of a superspreader adjuvant to reduce spray application volumes on avocados

Abstract

This study was undertaken to determine whether pesticide spray volumes on avocados could be substantially lowered with the use of a superspreader adjuvant and to identify an optimum spray volume and adjuvant rate to maximise spray retention Groundbased airblast applications of copper fungicide were made to 45 year old fruitbearing trees Spray retention was quantified on foliage and fruit at a range of canopy heights and positions Spray deposits on foliage were maintained or improved using reduced volume sprays (500700 litres/ha) incorporating the superspreader DuWett compared to the standard high volume treatment (2500 litres/ ha) The adjuvant maintained total spray deposits on fruit using 35 times less spray volume than is current standard practice There was no evidence of phytotoxicity on any fruit or foliage due to adjuvant sprays The study highlighted deficiencies in current spray application technology used on avocados