Integrated management of the onion thrips, Thrips tabaci in open field vegetables (IPMTRIPS)

The main objective of this project is the integrated management (IPM) of the onion thrips, Thrips tabaci. These tiny insects represent the most important pest in open field vegetables, including leeks, onions, sprouts and cabbage. They feed by puncturing holes in the plant cell and sucking the juice from the cell. This causes silver-grey stains, damage and growth retardation. The short life cycle and the ability to develop resistance to insecticides make T. tabaci difficult to combat. Therefore, the field vegetable sector urgently needs an integrated management strategy in which the commonly used pesticides are applied carefully and more attention will be given to prevention, pest follow-up and adapted cultural techniques that stimulate natural enemies.

With this LA-traject, we characterize the genetic structure of the onion thrips populations in Flanders and evaluate their differences in resistance to the most common insecticides. In addition, we improve the existing warning system by predicting thrips activity based on a day degree model established for the different target crops. We also assess cultural methods to control the onion thrips and stimulate the population of natural enemies. We investigate the use of natural enemies and their compatibility with chemical crop protection agents. We also aim to contribute to creating social acceptance of leeks and cabbages with limited thrips damage.

We aim to encourage the growers and the extension agents that are active in the cultivation of open field vegetables to adopt sustainable integrated management of the onion thrips. The aim is to convince growers to reduce the use of insecticides and to offer them knowledge about prevention and non-chemical control strategies such as cultural methods. As a result, the day degree model for T. tabaci in each target crop will be established and integrated into the thrips warning system. Using surveys we will evaluate the effectiveness of our public awareness campaign about the acceptability of cosmetic thrips damage on field vegetables in Flanders.