Adjuvant effects on the retention and uptake of spirotetramat insecticide sprays on kiwifruit

摘要

Spirotetramat (Movento~R) is a systemic insecticide that can control scale insects on kiwifruit. It must be tank-mixed with a spray adjuvant to maximise leaf uptake. This study investigated how two adjuvants, a penetrating oil and a superspreader, affected spray retention and uptake of spirotetramat into kiwifruit leaves, from dilute and concentrated spray mixes. Spray retention and distribution of airblast-applied, high volume, dilute sprays containing the oil adjuvant were good, but retention was reduced when sprays were concentrated. Concentrated sprays, containing the superspreader adjuvant, were retained and distributed similarly to the dilute sprays containing oil adjuvant. Spirotetramat uptake into foliage was generally low, but was greater with the oil penetrant than with the superspreader. Concentrating sprays and increasing adjuvant concentrations could increase insecticide uptake, as could combining the two adjuvants together in a spray. The potential of the adjuvants to maximise spirotetramat efficacy in concentrate sprays and to reduce residues at harvest is discussed.