Strawberries

Vegetable and Fruit News, Volume 13, Issue 7 (October 2022). Topics in this issue are Sensor Placement and Row Cover Impact on Fruit Rotting Diseases, Common Weed Survey, Testing for Soluble Salt in High Tunnels, Changes to the Whole-Farm Revenue Protection and Micro Farm Insurance Workshop, SARE Grant information, Apple Workshop, and Upcoming UME & UMES events

The cool, wet spring weather we have been experiencing favors slugs, so be on the lookout for slug damage. Slug damage may easily be confused for sap beetle feeding, but management of these pests is very different, so it is important to correctly identify the problem. Both pests can be common in matted row production. Authors: Sankara Ganesh, Maria Cramer, and Kelly Hamby, Department of Entomology, University of Maryland, College Park

This has been a ‘mitey’ spring so far with two spotted spider mites, broad mites and now cyclamen mites (by Bob Rouse) being found. Usually cyclamen mites (Phytonemus pallidus) cause much of their damage to bedding plants, but they can cause significant problems in strawberries too. Adult cyclamen mites are usually never seen as they are only a quarter of a mm long and a 20X hand lens or dissecting microscope is needed to see them. And unlike two spotted spider mites that prefer dry conditions, cyclamen mites thrive in humid conditions and is why they are primarily a greenhouse pest.

Cyclamen mites have been found in a few mid-Atlantic strawberry fields as well as more widespread to the south of us in North Carolina. So once we start to really warm up they may become more of a problem along with two spotted spider mites.

I visited some strawberry fields over the last few days in Maryland. Most of the strawberry fields were on plastic but some were matted row production and a few in high tunnels. With the cooler weather we have had of late I was surprised to still find low levels of mites in the fields, with a few hot spots of mites in some high tunnels. There was only one species of mite found: the two spotted spider mite, Tetranychus urticae.

While visiting some strawberry fields over the last few weeks, I ran into a few areas that had two spotted spider mite (TSSM) feeding. These were mostly in fields that had been using row cover. Spider mites Tetranychus urticae are well adapted to high-temperatures and can complete their life cycle in as little as 7 days when temperatures are > 80º F. The temperatures under row covers in the early part of our season were much above normal and rainfall was below normal leaving conditions hot and dry, which permitted spider mites (if present) to develop quickly. Warm dry conditions along with the nitrogen content of leaves greatly influence TSSM reproduction rate. Applying excessive nitrogen favors spider mite outbreaks.

I visited some strawberry fields over the last few weeks in Maryland and while most of the fields were on plastic, some were matted row production. Overall I found low levels of mites in most of the fields, with a few hot spots.

With the cooler weather we have had of late I was surprised to find low levels of mites in strawberry fields, with a few hot spots of mites in some high tunnels. There were two species of mites found: the two spotted spider mite, Tetranychus urticae and the cyclamen mite Phytonemus pallidus.

Cyclamen mites have been found in a few Mary-land strawberry fields in the last few weeks. They are not much of a problem now but when we start to warm up, they may become more of a problem along with two spotted spider mites.