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Early-season scouting sets stage for current and future crops

Planting time in NW MN.  Planting is both a stressful and exciting time of the year as farmers race to cover many acres in a short period of time.  Near the University of Minnesota’s NW Research and Outreach Center in Crookston, many farmers have finished planting both sugar beet and spring wheat acres and have moved on to corn and soybean.  Many fields are still occupied with tillage implements and anhydrous tanks as people work long hours to complete essential tasks before the 1.5 inches of rain forecast to start Thursday.   

Planting is just the first step.  But as most would agree, getting seed placed into the soil is just one of many milestones for the 2018 crop.  The seed will need to access enough moisture so that cells begin to swell and metabolic processes ramp up enough to allow the first root (called the radicle) to break through the seed coat during germination.  Much can happen between this initial swelling and the first hint of seedling emergence including a soil penetrating late frost, cooler soils that retard growth and development or rain followed by windy, warm conditions that causes crusting.  

Seeds and seedlings vulnerable.  Before they begin both taking up nutrients and producing sugars through photosynthesis, seeds and young seedlings rely on the nutrient reserves provided by either their cotyledons (soybean) or endosperm (corn).  Plants are stressed when they start from poor quality seed or lie in cool soils that delay emergence and growth.  This stress can often tip the balance in favor of hungry seed and seedling pathogens or insect larvae. 
Scouting can ID problems.  Scouting fields in the first weeks after planting can help to identify early-season issues such as poor, delayed or uneven emergence, seed and seedling disease or insect injury.  Should scouting identify a significant early-season issue, the next step is to determine whether to stick with the current crop or to risk replanting.  To help with this difficult decision, University of Minnesota Extension specialists have developed online tools to help weigh lost yield potential due to poor stands against costs associated with a shorter season crop and replanting.  These replant decision tools are available for both corn and soybean.
Disease losses and diagnosis.  Stand losses due to disease are an indication that a particular pathogen is present in the field.  This means that the next time susceptible varieties or hybrids are grown and conditions favor infection, your crop might be at risk.  

One resource that can help in diagnosis is the “SoybeanDisease Diagnostics Series” that was recently put together by North Dakota State University and University of Minnesota plant pathologists.  Included are pictures of root rots caused by true fungi such as Fusarium and Rhizoctonia solani and oomycetes like Pythium.  True fungi are more closely related to a grocery store’s button mushrooms while oomycetes are more closely related to plants.  Consequently, different seed treatment active ingredients provide protection against oomycetes and true fungi. 

We tend to speak less about corn seedling disease as most hybrid seed corn arrives at the farm gate treated with seed treatment fungicides and insecticides.  Soybean producers often have more seed treatment options, although depending upon the company from which seed is purchased the choices may be among no treatment, a ‘kitchen sink’ treatment package or treating seed yourself.  Even when seed treatments come ‘standard’ there can be situations in which poor germination conditions outlast the life of seed treatment active ingredients or pathogens evolve resistance to specific active ingredients.  Scouting revealed that Pythium species evolved to overcome seed treatment active ingredients in some Iowacorn fields in 2012.  

Two additional resources that might be of use when selecting seed treatment fungicides are University of Wisconsin Extension’s “What’son your seed?” and Purdue University’s “FungicideEfficacy for Control of Soybean Seedling Disease”. 

Bottom line: scouting can provide essential information of use for this and future crops.  Let’s let early-season scouting set the pace for the 2018 cropping season!

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