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Crop
condition (please send a couple weeks of warm, dry weather)
It all depends on planting date and rainfall amounts.
We were behind on planting progress and now degree days and crop development.
Crops look better than might be expected (considering the spring weather)
along the paths between Lamberton and Morris the past two weeks. There
are early planted corn fields that avoided excessive rain looking pretty
darn good with corn closing rows. Crops in other areas range from adequate
to fields with deep sprayer ruts, delayed and stunted crop. Occasional
drown outs testify to the amount spring precipitation. Spring wheat looks
adequate to unbelievably good in the fields that I have driven by. Soybean
growth has been painfully slow and has me a bit concerned. Chlorosis symptoms
have started to appear on unusually small beans (unifoliate in some cases).
Moisture influences soil chemistry and reduced root function from saturated
soils and presumably some root disease are not helping.
I have been feeling a bit optimistic lately. It is an
unfamiliar and uncomfortable feeling and I may need to take a trip south
to restore my equilibrium. The jungle telegraph reports from south of
Highway 14 indicate that conditions are worse there.
No, it's not anything like the abnormally fast start
we had in 2007 but it could be much worse. The problems in parts of Southeast
MN and neighboring corn-belt states are all over the media. Most producers
in much of south central and western MN can consider themselves fortunate.
Those of you have survived previous weather crisis of 1976, 1988 and 1993
and many other, more geographically limited, problems will find it easier
to put this season in perspective. There should even be some knee high
corn by the 4th with some good weather.
Colorful Corn
Root problems become increasingly
apparent as growing corn and soybean demands for soil nutrients increase.
Brown corn is beyond hope. Yellow and purple stunted corn plants display
nutrient deficiencies but these may be a secondary result of plants with
poorly functioning root systems struggling in saturated soils. They need
warm, dry weather. On the other hand, extreme heat would be hard on plants
in saturated soils until they develop/regenerate root systems. Supplemental
nitrogen will not help while plant roots are drowning in an anaerobic
soil soup. When it dries (oops, there's that optimism again), a row cultivation
may help aerate crusted, sealed soils. Supplemental N guidelines, as well
as other wet crop info are described in the latest Minnesota
Crop E-news.
Missing
Plants
Germ has been
lower than typical in some soybean seed lots. Based on seedling symptoms,
I suspect but cannot confirm disease as part of the equation. Struggling
emergence has been further hurt by seedling disease. There is a higher
than normal amount of damped off corn and soybeans this year and not always
in low areas. One Murray County corn field had more problems in the higher,
lighter soils in the field, indicating that temperature may have been
as or more important than soil moisture content. Damping off has been
observed in corn (typically treated with seed applied fungicides) and
soybean fields with and without seed applied fungicides. Although I haven't
done the math yet, I don't expect much, if any difference between fungicide
treated and untreated soybeans stands in a trial at the University of
Minnesota, Southwest Research and Outreach Center (SWROC). Think type,
intensity and duration of seedling disease when evaluating what went right
or wrong. In most cases stands are ok.
Miscellaneous Insects
So far 2008 has been refreshingly
low-key with respect to insect problems.
Bean leaf beetle
- Over-wintering adults are out there but in areas I have examined low
in number. Early vegetative soybeans can lose a large percentage of leaf
area (up to 50%) without yield loss.
Potato leafhopper
- We have not yet found potato leafhopper in alfalfa but did see our first
adult in soybean on 6/16/08. Pea aphids are common in alfalfa again
this spring.
In spite of the depressing
number of plants examined, I have not yet observed soybean aphids
in soybeans this spring. I will visit prime soybean aphid territory later
this week. Dave Ragsdale and crew have observed a few soybean aphids on
buckthorn.
Stand reducing insects
reports have been fairly minimal. I know of one Brown County field that
was treated for black cutworm. I received a call about odd looking/behaving
cutworms killing the growing point at the edge of a triple-stack planted
corn field. The description of damage sounded similar to hop vine borer.
When I saw the specimens, I was baffled. I am getting the Lepidoptera
specimens to more some knowledgeable types and will post pictures and
hopefully a solution.
Wheat
Winter wheat
varieties ranged from boot stage to headed on 6/13. The cool, rainy weather
has resulted in moderate to high incidence (percent plants infected) of
the foliar diseases Tan spot, Septoria, Powdery mildew
and wheat leaf rust. Wheat leaf rust was the least prevalent and
not observed on all varieties. Tan spot is typically rare in SWROC
plots but this year's winter wheat trial was planted close to a source
of inoculum (last year's winter wheat trial). I expect that the powdery
mildew will disappear with warm, sunny weather.
Spring wheat, on another
part of the SWROC, was jointing and had much less disease. I did not observe
any rust on spring wheat. I'd pay close attention to spring wheat diseases
as heading approaches.
Small grain aphids, primarily
bird-cherry oat aphid are present but have not reached threshold levels
at the SWROC.
Web Resources
Web
Resources Pesticide Labels- To obtain current labels and MSDS for agricultural
chemicals see the CDMS website.
Weather - To keep up to
date on all the crop weather details around the state during the growing
season see:
Lamberton
Morris
Crookston
Waseca
The MN
climatology working group website provides an abundance of facts.
http://climate.umn.edu/ddgen/ddgen.asp
allows you to calculate degree-day accumulations across Minnesota. The
temperatures are updated once a week on Monday.
Contrary to rumors,
I am not too busy to visit with people about crop and pest conditions.
Bruce Potter
IPM Specialist SW Minnesota
University of Minnesota
Extension Service
Department of Entomology
University of Minnesota
Southwest Research and Outreach
Center
23669 130th Street
Lamberton,
MN 56152
Ph:
507.752.5066
Fax: 507.752.5097
E-mail: bpotter@umn.edu
http://swroc.cfans.umn.edu/SWMNPEST/swmnpest.htm
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