Thrips


Another pest you will typically encounter are thrips, like the western flower thrips (Frankliniella occidentalis).

In some locations, thrips can be a serious pest. When population increases, you will start seeing damaged fruits typically bronze in color (partially or fully) and not marketable. The damage seems to be from immature thrips feeding on the fruit surface. Thrips are attracted to yellow sticky cards, so using those are a good monitoring practice. Adult thrips like to hang out in the flowers, and if you blow gently on the flower, they will come out.

However, a predator of Thrips, Miniature Pirate Bug (Orius spp.) eats Thrips, and anything else its size (or smaller). Since it will feed on all the above mentioned pests and more besides, it is a good one to periodically introduce. If your crop is big enough, Orius spp. can develop sustainable populations in the crop. It can fly, so it can move around to find prey, but if pest populations drop too low, it will also leave for greener pastures. Orius is sensitive to photoperiod so it will go into a “hibernation” as the days shorten, and the critical photoperiod for short day varieties is too short to keep them awake. If however you are producing everbearing varieties, and are providing 16 hours of photoperiod, Orius should remain active.

Amblydromalus limonicus is a predatory mite that is not affected by photoperiod and stays active in the cooler night temperatures needed in greenhouse strawberry production.

There are other pests that may assail your berries. Again, the UC Davis site covers them very well. The site also covers strawberry plant diseases.

Unless otherwise indicated, all of the images in this section are from the UC Davis IPM site and are used with permission from the University of California Statewide IPM Program, Jack Kelly Clark, photographer.