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!
