SOYBEAN SEED TREATMENT
Treating soybean seed with a fungicide or fungicide plus insecticide generally does not increase yield when high-quality seed is planted under North Dakota conditions. Seed treatment benefits seedlots that are damaged by disease, frost, excessive seed coat breakage and age. Seed treatment for soybean should be considered in these situations: 1) when poor-quality seed is used for planting (e.g. germination below 80 percent), 2) when early-season disease (bacterial blights and seedling blights) is needed, and 3) when planting early into cool and wet soils, especially in reduced tillage.
Certain fungicides may injure or kill N-fixing rhizobia bacteria which are used for seed inoculation. Thiram has no effect on rhizobia nodulation; metalaxyl has little or no effect on nodulation; carboxin reduces nodulation by about 25%; and captan and PCNB very severely reduce nodulation.
Check NDSU Extension Service circular PP-622 at http://www.ext.nodak.edu/extpubs/plantsci/pests/pp622w.htm for recommendations on current registered seed treatments.
POST-EMERGENCE WILD OAT HERBICIDE CHOICES IN WHEAT
Post-emergence herbicide choices for wild oat control in wheat include Achieve, Assert, Avenge, Cheyenne, Discover, Everest, Hoelon, Puma, and Tiller. The following is a listing of herbicide application rates and timing for wild oat and wheat, approximate costs, and additional weeds controlled.
Application rate = 7 oz WDG/acre. Cost = $14/acre. Wild oat stage = 1- to 6-leaf stage. Wheat stage = 2-leaf to boot. Do not apply on spring wheat east of ND Hwy 281 or in the following counties: Dickey, LaMoure, Stutsman, Foster, Eddy, Ramsey, and Towner. Also controls foxtail.
Application rate = 1 to 1.5 pt/acre. Cost = $10.50-16/acre. Wild oat stage = 1- to 4-leaf. Wheat stage = 2-leaf to jointing. Also controls wild mustard.
Application rate = 2.5 to 4 pt/acre. Cost = $12.50 -19.25/acre. Wild oat stage = 3- to 5-leaf. Wheat stage = prior to flag leaf emergence.
Application rate = 40 acres/box. Cost = $16.25/acre. Wild oat stage = 1- to 4-leaf. Wheat stage (HRS or winter wheat only) = 3-leaf to end of tillering (6-leaf). Also controls green foxtail and barnyardgrass, and numerous annual broadleaf weeds.
Application rate = 3.2 fl oz/acre. Cost = $15.25/acre. Wild oat stage = 1- to 6-leaf. Wheat stage (HRS and durum wheat only) = 2-leaf to emergence of 4th tiller. Also controls foxtail, barnyardgrass, and volunteer corn.
Application rate = 0.4 to 0.6 oz WDG/acre. Cost = $8-12/acre. Wild oat stage = up to 4 leaves. Wheat stage (HRS and durum wheat only) = 1- to 6-leaf. Also controls green foxtail and suppresses several other weeds.
Application rate = 2 to 2.66 pt/acre. Cost = $15-20/acre. Wild oat stage = 1- to 3-leaf. Wheat stage = up to 4-leaf. Also controls green and yellow foxtail.
Application rate = 0.66 pt/acre. Wild oat stage = 1-leaf to 2-tiller. Wheat stage (HRS and durum wheat only) = 1-leaf to 60 days before harvest. Cost = $15/acre. Also controls green and yellow foxtail, barnyardgrass, and volunteer corn.
Application rate = 1.7 pt/acre. Cost = $18.50/acre. Wild oat stage = 2-leaf to 2-tiller. Wheat stage (HRS and HRW wheat only) = 3- to 4-leaf up to 6-leaf. Also controls green and yellow foxtail, barnyardgrass, and several annual broadleaf weeds.
Refer to herbicide labels and NDSU Extension Service circular W-253 "2001 North Dakota Weed Control Guide" for required information on use and other details including adjuvant and tank mixtures.