New research is shining a light on mealybug trends in New Zealand apple orchards, giving growers valuable information to help manage these persistent pests.
Over the past few years, mealybug detections at harvest have been on the rise, prompting NZAPI to team up with the Bioeconomy Science Institute for a closer look.
The latest study – led by Senior Scientist Vaughn Bell – ran from September 2024 to June 2025 and expanded monitoring from Hawke’s Bay to include Tasman orchards for the first time.
Bell, who specialises in Ecological Pest Management, says he hopes the research will raise awareness of this pest group.
“It’s an old saying, but it remains relevant to this issue – knowledge is power,” says Bell. “You cannot manage effectively that which is not monitored adequately. Whether talking pests or diseases – old-school, eyes open, remains important.”
Key Findings
Pheromone trapping across both regions confirmed that citrophilus mealybug remains the most prevalent species. However, the longtailed mealybug was also common in some Hawke’s Bay blocks and, notably, was the dominant species in one Tasman orchard. The obscure mealybug was largely absent from Tasman but present at low levels in all Hawke’s Bay sites.
Seasonal monitoring showed that while the expected peaks in male mealybug catches for the first two generations (spring and summer) were inconsistent, a clear and relatively consistent third-generation peak was observed in autumn across both regions.
Pre-harvest fruit inspections revealed variable infestation rates. In Hawke’s Bay, three out of seven orchards had 5–19% of apples infested, mostly with citrophilus mealybug. The remaining blocks had low or undetectable levels. Sooty mould around the calyx was a reliable indicator of mealybug presence inside the fruit. In Tasman, the longtailed mealybug was more common, with three orchards recording infestation rates between 4% and 45%. Other sites had minimal mealybug presence.
