Written collaboratively by Adam Varenhorst, Patrick Wagner, Philip Rozeboom, Brad McManus, Jonathan Kleinjan, and Sunish Sehgal.
Originally Submitted: August 31, 2023
As winter wheat planting rapidly approaches, there are many factors that should be considered. One of those factors is choosing a planting date. For optimal yields, it is recommended that winter wheat is planted between September 10 through October 10 in South Dakota. This usually provides the developing wheat a window of 8 to 12 weeks for growth before the first hard frost. However, due to Hessian fly infestations in central South Dakota, planting in early September is likely to increase Hessian fly issues for 2023-2024 in some areas.
Based on Hessian-fly-free (also known as fly-safe) dates used in North Dakota (which are after September 15 in Northern North Dakota and after September 30 in Southern North Dakota), the recommendations would be that wheat in northern South Dakota is planted after September 30 and after October 15 for the southern half of the state. However, planting after October 15 may have negative agronomic impacts, and, for that reason, we are recommending planting after October 7 for the southern half of South Dakota and September 25 for the northern half of the state. We plan to evaluate these fly-free dates in the next few years.
The second generation of Hessian flies will begin to emerge during August and September. After emerging, Hessian fly adults only live 1 to 4 days, which is why delaying winter wheat planting can greatly reduce the success of the second generation (fall population) of Hessian flies in infesting winter wheat.
- Resistant Cultivars: Planting wheat cultivars resistant to Hessian fly can help to suppress populations. There are currently 34 Hessian-fly-resistant genes identified. However, it is important to rotate cultivars to help eliminate the chance of pests developing resistance. For South Dakota, the SDSU Winter Wheat Breeding Program has observed low resistance in the variety ‘Winner’ and moderate resistance in the new variety ‘South Dakota Pheasant’ (which is a new release for fall 2023). To purchase SDSU Foundation Seed, call of text Jack Ingemansen at 605-690-8358 or email your request.
- Fly-Free Dates: Avoid planting (if possible) until after a fly-free date. Fly-free dates have been used to determine when Hessian fly activity has ceased during the fall, and planting is considered “safe.” However, these dates can vary depending on many environmental factors.
- Crop Rotation: Hessian flies have a very limited host range, with wheat being the preferred host. Avoid planting wheat back-to-back where problems with Hessian flies have previously occurred. Rye and barley are also suitable hosts.
- Weed Removal: Remove any volunteer wheat, rye or barley prior to planting wheat to prevent “green bridges” into the new crop.