A one-year investigation into the relative abundance and species of mealybug parasitoids in Gisborne vineyards commenced last week.

The trial has been made possible through funding from GisVin via Gisborne Wine Growers Society, and NZ Wine, in partnership with BRI.

The idea for the trial arose after several Gisborne growers met and agreed that they would like to improve their understanding of what beneficial insects live in and around their vineyards and what impacts vineyard practices, such as cover cropping and spray management, might be having on these species. Mealybug is still considered a pest in Gisborne vineyards and growers have questioned why outbreaks vary between vineyards; what environmental conditions and management factors might be influencing seasonal mealy bug populations in their vineyards?

Dr Vaughn Bell of Plant and Food Research has successfully investigated what species of parasitoids are attacking mealy bugs in vineyards using sentinel mealybugs, and pheromone trapping to monitor the population of adult male mealybugs in vineyards in Hawkes Bay and Marlborough. These two methods will be used in three different Gisborne vineyards to assess parasitoid species and abundance, along with the seasonal lifecycle pattern of male mealybugs. These observations and data will help inform growers of local parasitoid and pest population dynamics.

In addition, the trial links well with other projects investigating integrated mealybug management tools. The results from the Gisborne trial could be compared with data collected in other regions, which will improve industry knowledge concerning the wider distribution of mealybug and beneficial insect species.

An improved understanding of how insecticide use may impact on the levels of beneficial insects could offer growers the confidence to reduce their reliance on broad spectrum insecticide inputs and enable a balanced, well-functioning eco-system. Enhancing vineyard eco-system functioning is a priority for many growers in Gisborne and other NZ wine regions.

Recently Len Ibbotson, BRI Viticulture Extension & Research Manager, & Dr Vaughn Bell met with a few growers in Gisborne to discuss mealybug management and deploy pheromone traps at the trial sites.

BRI & NZ Winegrowers would once again like to thank GisVin for their contribution to this project and supporting their local industry.