A few folks are starting to spray spider mites in isolated fields, so I wanted to put forth a couple of reminders.  First, UT recommends treatment when 30-50% of plants are showing symptoms of spider mite injury and spider mites are still present.  Most experienced people recognize that managing spider mites requires a some professional judgement.  You may have a very few mites on a lot of plants, or a lot of mites in isolated areas or field edges.  Sometimes, a perimeter application of miticide can slow the spread of spider mites across the field.  A key thing to look for in deciding whether treatment is necessary is if infested areas are beginning to expand in size.  This can occur pretty quickly in hot and dry conditions.

We’ve had to do a lot of spraying for thrips and plant bugs in many fields, so this may aggravate the situation.  There are many good miticides including Oberon, Agri-Mek, Zeal, Portal and Dicofol (see complete list and suggested rates here).  Unfortunately, the price of most miticides is pretty high with the exception of abamectin products such as Agri-Mek, Abba, Zoro, etc.   Also note that some of my counterparts in surrounding states have reported less than adequate control with abamectin products.  We’ve relied heavily on these products during the last 4-5 years, so it is possible resistance is developing.  Thus, I suggest using a minimum of 6-10 oz/acre (assuming a 0.15 Lb formulation) and watching closely after application to make sure adequate control was achieved.  Please report suspected control failures after using one of the abamectin products.  Also note that bifenthrin and dimethoate products such as Brigade typically do not provide consistent control of spider mites, at least until later in the season.