by Dr. Calvin Trostle, Extension Agronomy, Lubbock, 806-746-6101, ctrostle@ag.tamu.edu
Dr. Ed Bynum, Extension Entomology, Amarillo, 806-677-5600, ebynum@ag.tamu.edu
Wherever sunflowers are grown in Texas (this year mostly in the High Plains), a standard and essential part of managing the crop is controlling sunflower (head) moth. When moth pressure is moderate damage to the sunflower crop from the larval feeding alone has an economic impact, and the subsequent opportunistic Rhizopus head rot infection can devastate yields.
Sunflower moth control measures in our opinion rank in the following order: 1) timing, 2) effective spray coverage, and 3) the chemical you use. This may surprise some as there may be differences among insecticides, but any labeled product should provide good control if timing and coverage are good.
• Timing. In general, AgriLife Extension entomologists recommend that the first spray for more traditional insecticides occur when no more than 20% of the individual plants in the field are at R5.0 or higher stage of bloom. Many producers prefer to spray 1-2 days sooner. Newer chemicals on the market, primarily Dupont’s Prevathon, are often recommend to spray at initial bloom or even pre—bloom. AgriLife is testing this recommendation in the Lower Rio Grande Valley, Lubbock, and Amarillo. At this time we do not recommend pre-bloom sprays. What constitutes “bloom” on an individual sunflower head or a field? Examine the color pictures in “Sunflower Bloom Growth Staging for Sunflower Moth Control,” at http://lubbock.tamu.edu/files/2016/06/Sunflower-Bloom-Growth-Staging-for-Sunflower-Head-Moth-Control.pdf
• Coverage. Most chemicals labeled for sunflower insect control recommend three gallons per acre by air. A few though (including Prevathon) recommend only 2 gallons per acre. We believe <3 gallons/A is insufficient to achieve reliable control. In fact, AgriLife Extension suggests you spray 4 and even 5 gallons per acre carrier volume, and pay the additional cost. Ground rigs can use 10 gallons per acre or more for better coverage.
• Chemical. You may view Texas sunflower insects and a list of suggested control chemicals in “Managing Insect Pests of Texas Sunflower” (E-579, 2009, see http://lubbock.tamu.edu/files/2014/06/Managing-Insect-Pests-of-Texas-Sunflowers-2009-E-579.pdf) though there are additional chemicals on the market now labeled for sunflower including Prevathon, Besiege (a mix of Prevathon and pyrethroid), and Belt. We are testing them all for effective control of sunflower moth. For additional sunflower insect information view the online resource “Texas Sunflower Insects Summary 2016” at http://lubbock.tamu.edu/programs/crops/sunflowers/
Other resources for Texas sunflower are on our sunflower page at http://lubbock.tamu.edu/programs/crops/sunflowers/. For specific questions about sunflower consult your area IPM Extension agent if you have one, or sunflower Extension entomologist Dr. Ed Bynum, Amarillo.
Calvin Trostle
Professor and Extension Specialist
Lubbock, TX
803.746.6101
ctrostle@ag.tamu.edu