Time To Spray Aphids In Wheat?

 JACKSON,   .TENN.
    I published an article about aphid management in wheat last October. In this article, I mentioned yield increases resulting from a foliar application of insecticides for aphids in mid to late February. In our testing, we’ve seen an average yield increase of about a 6-7 bushels per acre by making an insecticide application in late February (see table below). This increase was not always statistically significant, but the response has been consistent enough that UT has changed it management recommendations to the following.
   “An insecticide seed treatment such as Gaucho, Cruiser and NipsIt Inside can be used to reduce transmission of barley yellow dwarf virus. Data suggests that early planted wheat is most likely to benefit from use of a seed treatment. If a seed treatment is not used, a foliar insecticide application for aphid control during the fall (e.g., approximately 30 days after planting) or late winter (prior to March) can also reduce transmission of barley yellow dwarf virus. These applications should be applied before populations exceed 8 aphids per foot of row.”
   A couple of additional points … The most important component is to make applications before aphids have become well established in the field. The potential benefits of a foliar application may be negligible if aphids have already had the opportunity to transmit barley yellow dwarf virus.
   It is very difficult to find aphids during January and February, at least in Tennessee. They are often present in low numbers and hiding from the cold weather. However, our data has shown a substantial reduction in aphid populations several weeks after this applications (really for the remainder of the spring).
    The value of foliar insecticide application will almost certainly be less if an insecticide seed treatment was used. Our data has shown a reduction in winter- and spring-time aphid populations stemming from the use of a seed treatment.
    Pyrethroid insecticides are typically recommended for the control of aphids include including Karate/Warrior, Baythroid, Mustang Max and Declare. Other options include dimethoate, Lannate and Methyl parathion. I do not expect any problems mixing these products with herbicides or fertilizer, but you should test for mixing compatability beforehand. Δ
DR. SCOTT STEWART: IPM Extension Specialist, University of Tennessee