A few weeks ago, this post outlined some of the insects that could be found in strawberries in the pre-harvest stage. Now, in the harvest stage, we can still see problems with some insects. Spidermites (actually not an insect) can build up quickly to numbers that can slow down the plants and keep them from producing to their full potential. The plant in the photo below has a severe infestation of mites. Feeding damage is causing the leaves to curl.
Below, this leaf is showing some yellow stippling. Another symptom of spidermite feeding damage.
The photo below shows the back side of the same leaf. They are difficult to see with the naked eye, but there are lots of spidermites on this leaf. Sometimes some webbing will be present, also.
Here is a photo of some plants with slightly more subtle symptoms. Still you can see the leaf curl.
Weekly scouting is an important part of protecting your plants from spidermites. Powell Smith, Vegetable and Small Fruit Specialist with Clemson Extension recommends the following scouting method and threshold. In a field smaller than 5 acres look at 50 leaflets. In a field larger than 5 acres look at 100 leaflets. When over 4% of the leaflets are infested, treat with an effective miticide. To see which miticides are labeled and their rates, check out pages 10 and 11 of the Southeastern Strawberry IPM Guide.
For more production information look at the Southeastern Regional Small Fruit Consortium website.