Cropping Q &A in February and March
• What is the economic advantage of utilizing Thimet 20-G for wheat stem sawfly control? Trials in Montana have demonstrated a 64-100% reduction in damage measured as stem cutting by larvae. The trials also found that farmers can attain a 5.4 bushel per acre yield recovery for spring wheat and a 6.1 bushel per acre yield recovery for winter wheat.
• How safe is Thimet 20-G? Thimet 20-G is fatal if swallowed, inhaled or absorbed through the skin. Do not breathe dust. Do not get in eyes, on skin, or on clothing. Thimet 20-G is also corrosive, and can cause irreversible eye damage. Applicators must be in an enclosed cab that meets the definition in the WPS for dermal protection. In addition, the applicator must wear a long sleeved shirt, long pants, shoes plus socks while within the cab. The enclosed cab must also provide respiratory protection equivalent to a dust/mist filtering respirator or the applicator must wear a NIOSH approved respirator with any N, R, P, or HE filter (prefix TC-21C).
• I have wheat streak mosaic in my winter wheat. How do I manage this disease? In most cases, a limited infection of winter wheat will not cause severe yield loss. Obviously the grower would need to be very attentive to their green bridge that fall. Crop termination using glyphosate will allow the mite 5-7 days (or more) to move downwind into anything green. Tillage is a better option for crop termination but is not always feasible. Swathing is an option later in the season. Spring wheat and barley are more susceptible than winter wheat, and have larger yield losses. Given the burn-down time of glyphosate and planting windows with weather, you often end up with more of a disaster on your hands when replacing winter wheat with a spring cereal. If nothing else, do not apply any additional nitrogen to the crop in order to limit spread of the disease. Any yield gain from nitrogen will be taken away by the virus, and the virus will spread more with increased mite replication on fertilized plants.
Additional cropping information is available at the Chouteau County Extension office at 622-3751. We are located in the basement of the Chouteau County courthouse
Montana State University, U.S. Department of Agriculture and Montana Counties Cooperating. MSU Extension is an equal opportunity/affirmative action provider of educational outreach.
