What are practical ways to control or eliminate russet mites (tomatoes)? We are not finding many pesticides or IPM methods that are known to be effective. We have clients in OR and other states with this issue. Thank you, Michael Lodge First Amendment Soil Company 970-901-5105
Oregon insect issues
There are two "keys" to managing any of the tiny leaf-feeding mites, namely early detection/treatment and complete coverage with miticide. Most growers unfortunately fail in both these areas, at least some of the time.
If you wait to see damage from tomato russet mite it is probably to late. You must scout in early season and apply control measures at the first sign of the mites before damage occurs, or start treating prophylactically early in the season.
Coverage is the second issue. Miticide must be applied so that you get complete coverage of both surfaces of the leaf, this is easier early season when the canopy is less dense.
Fortunately the miticides that will work are very low in toxicity and considered organic in most cases (be sure to check labels carefully). Insecticidal soap (www.livingwithbugs.com/insecticidal_soap.html) either alone or combined with neem oil insecticide (www.livingwithbugs.com/neem_oil.html) are good choices. Since both soap and neem oil have very little residual activity it is important to repeat application throughout the season. A little testing by the grower is needed to determine the best application interval but 7 days would be a good starting point. Also, test for leaf damage especially from the soaps.
These suggestions are targeted at small growers or home gardeners, large commercial growers will likely use more specific miticides.
Also, take a look at https://extension.usu.edu/files/publications/factsheet/eriophyid-mites2010.pdf for an overview of other eriophyid mites.
Thank you for your response.