The measures that are reviewed are based on nature-inclusive agriculture, including the application of natural enemies of thrips and other pest control measures. The objective here is to limit the damage to onion crops caused by thrips to an acceptably low level, using both above- and below-ground biodiversity.
Strategy for thrips control
In addition to a regional monitoring system, a thrips control strategy will become available that will also enable determining the damage threshold and choosing which measures and means to apply. These include any natural enemies already present or to be cultivated, and repellents (e.g. luring them away using pheromones or by applying confusing odorants). Knowledge on the lifecycle of thrips, their natural enemies that keep their population numbers low, as well as experience with applying pheromones, will result in effective thrips control methods that do not require the use of chemicals. At 10 locations in the Netherlands, the presence of both thrips and their natural enemies in onion crops are being monitored, annually.
The main research questions are:
- How do onion thrips populations develop over time (number of generations)?
- What are the conditions that determine thrips population growth (e.g. climate, temperature)?
- How can regional thrips populations be monitored?
- How is the damage threshold determined and what data are required?
- Which of the soil-borne natural enemies affect thrips population development?
- What are the measures that will support population growth in their natural enemies?
- What are the effects of nature-inclusive measures on biodiversity?
By utilising the knowledge and results from this research project, onion thrips populations can be kept under control without the use of harmful pesticides. This knowledge will become available, in the near future, as a result of the collaboration with supply companies Agrifirm and CZAV.