Thrips in strawberries

Thrips is a problem that is not to be solved quickly. We must make use of the available means and apply them sensibly. It is, as always, very important to start a new crop in as clean conditions as possible. The crop systems that allow the survival of thrips, such as continuous cropping of strawberries under plastic tunnels, present a problem. Here, the thrips can easily come through the winter and feast in the spring on the first opening flowers. Such a crop may present a danger to the other crops on that farm. It is also important to be able to monitor well a thrips population and, if necessary, to trap it with the help of blue sticky plates and blue sticky rolls. Consider also the yellow sticky rolls that are successfully used against whitefly.A weekly check of these rolls is necessary!

As regards the biological control, at present we still rely on the use of predatory mites. The best to use is the predatory mites A. cucumeris , they are the best adapted to the temperatures of the strawberry crop. By introducing them in good time, it is possible to catch the first present thrips larvae and to suppress a first explosive growth of thrips. Depending on the situation on the farm and in consultation with your adviser, you may have to repeat the procedure. Do not wait too long, you must bear in mind that A. cucumeris catches only the small larvae of thrips. It is best not to use any sulphur against mildew as it causes a lot of trouble for the present predatory mites.
We can also make use of the predatory bugs (Orius ). They are really well “specialised” in consuming thrips (adults). However, the effect of these predatory bugs is often very unstable and characterised by a very slow population growth at somewhat colder temperatures than those in the strawberries. Nevertheless, as Orius bugs can naturally ‘fly’ into the farms and be combined with the introduced predatory mites, these crops may be protected against damage from thrips.
To be continued in our next newsletter ………..