Grape Days 2024 | Improving the outcomes of mealybug insecticide | Dr Vaughn Bell & Andrew Blakeman

Mealybugs spread grapevine viruses and generate honeydew supporting sooty mould. Due to these risks, the Bragato Research Institute funded a three-year project from 2020. The goal was to improve industry understanding and use of insecticides targeting mealybugs on grapevines. We collaborated with growers in Gisborne, Hawke’s Bay, and Marlborough.
Spray diaries (2018 to 2022) were reviewed for mealybug insecticide use, product choice, and product dose rates per unit of area. Information was linked to vine planting density and the approximate canopy size (at the time of use) to determine the point of first runoff (POR) and the likelihood of product under- or over-dosing.
We found variable compliance with labels and best practice: application timing was too early and application volumes above POR; spray timing and/or spray volumes were incompatible with the size of the canopy target; under-dosing of chemical rates; and too few insecticides were applied when circumstances warranted more use. We review the findings and provide recommendations to improve the outcomes of mealybug insecticide use in vineyards.
This presentation was at Grape Days Marlborough, 2024.