A new project trialling the use of natural enemies for the control of a major pest in strawberries will also potentially benefit other crops where the same pest is difficult to manage.
A Lighter Touch is partnering with Strawberry Growers New Zealand in a project focusing on the control of thrips, in particular the species Frankliniella intonsa (intonsa), which continues to be a limiting pest of strawberries in mid-summer in the Auckland and Waikato regions.
The project is also being sponsored by Barker’s of Geraldine, and Bioforce is supporting the project through provision of the biological control agents (BCAs).
The project will involve landscape scouting for intonsa thrips to determine which plants the thrips population builds up on prior to migrating onto strawberry crops in mid-summer.
The second component of the project will test the effectiveness of three different predatory insects, or BCAs, in controlling pest thrips, particularly intonsa. The efficacy of a minute pirate bug, a green lacewing, and predatory mites against intonsa thrips will be investigated on strawberries in a greenhouse setting.
The two-step approach of the project reflects the acknowledgement that the release of predatory insects within the crop alone is unlikely to sufficiently control a large and rapid influx of the pest. Learning which plants in the landscape the thrips population is building up on creates the potential to introduce biocontrols in spring to host plants, preventing the later season mass migration of intonsa adults into strawberry crops.
Thrips are especially problematic for tunnel strawberry growers, with the pest arriving into the crop from the surrounding landscape, leading to a high percentage of unmarketable fruit for four months in mid to late summer.
Intonsa thrips are also known to be pests of vegetable crops, meaning knowledge from the project may provide a biocontrol option for these crops.
In addition, the biological control agents being tested are known to be generalist predators, and it is expected their testing on intonsa thrips will be applicable to other thrips species. This means the project findings will be useful for other crops with thrips pests.
Findings from the project will be shared with strawberry growers as it progresses. The project is now underway and will be complete in September 2025.
