JUNE 1996
Wheat & Barley Production Tips
By Jochum Wiersma
University of Minnesota small grains specialist
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Prairie Grains is the
official publication of
the Minnesota
Association of
Wheat Growers,
North Dakota Grain Growers Association,
South Dakota Wheat,
Inc., and the
Minnesota Barley
Growers Association.
Take time for a field day
I encourage all growers to attend the nearest experiment station plot tour or field day this summer. They usually fall between mid June and mid July. Your county extension educator will likely promote field days near you; many extension educators even sponsor their own county event. They are well worth your time. Your checkoff dollars help support this research, and there is no better way to see your support in action than to review research progress and visit with crop scientists at a summer field day.
MN yield trials and demo plots
A number of additional wheat and barley yield trials have been planted at various Minnesota sites this year; 14 trials at nine locations have been added to the experiment station yield trials and at two locations in northern Minnesota (Stephen and Roseau). The purpose of these additional yield trials is not only to gather more performance data, but also to serve as demonstration plots. All the recent releases as well as some "golden oldies" are included for you to review.
Plot locations are Comstock, Ulen, Ada, Mahnomen, Fosston, Red Lake Falls, Brooks, East Grand Forks, Argyle, Kennedy and Greenbush. Contact your extension educators for details. I encourage you to take a look at the new releases. There may be organized field plot tours at these sites, but don't hesitate to visit a location on your own. Each site will have a box with a complimentary description of the trial to help you find your way around. Keep in mind though, that these are yield trials from which crop scientists wish to extract data; so take care not to pull or trample plants in the trials, which could render plot studies useless.
Early season fungicide use on wheat
Wet soils + heavy dews will favor early infection by tan spot or Septoria fungi, especially if wheat is in wheat stubble. Wheat in the 4-5 leaf stage may benefit from use of foliar fungicides, if disease is present.
The fungicide options available include: a 1 lb. rate of mancozeb (Dithane, Penncozeb, Manzate, or Clean Crop) at about $2.75/acre - or 2 fl. oz./acre of Tilt at about $4.25/acre. Mancozeb are protectant fungicides while Tilt has locally systemic activity. Tilt received a Section 2(ee) label for North Dakota in February, 1995, for the reduced weight (2 fl. oz.) to be used on wheat, if tanspot is present early. NDSU trials across sites, years and cultivars indicate a variable response to early season fungicides. Average yield responses to mancozeb in 1992 and 1993 ranged from 5 - 7%. In 1994, responses were more variable, from 0% to a 14.5% yield increase in a north central site. Responses to a 2 oz. Rate of Tilt in 1994 also were variable, but up to a 12% response at Wishek, ND. Interested producers may mix these fungicides with certain herbicides if allowed or not prohibited by the label. Producers must consult the herbicide/fungicide labels for restrictions on mixing, and for any need or restriction relating to adjuvants.
Orange Wheat Blossom Midge
Another reminder to review the video about this tiny orange insect before your wheat crop starts heading. It is available through your county extension educator, or by contacting the Minnesota Wheat Council, 1-800-242-6118. The Minnesota Extension Service will organize roadside meetings in the evening hours this summer to help you familiarize yourself with the insect and the correct ways of scouting. Dates and locations will be announced later.
Building your own emergence traps like the ones used in the video are a good way to familiarize yourself with midge, although they do not help in determining economic threshold for spraying. That decision can only be made out in the field during dusk. There is good news in that a special local needs request for use of Lorsban 4E-SG in controlling the insect has been approved in North Dakota and Minnesota. Availability of treatment supplies should be adequate if control becomes necessary.
Preventing Herbicide Resistance
According to Bev Durgan, U of M extension weed scientist, herbicide resistant weeds are becoming more common every year. The most widespread problem is resistance to diclofop (Hoelon) and fenoxaprop (Tiller, Cheyenne) products in wild oats. Cases have been reported and confirmed throughout the Red River Valley and the beach ridge area from Clay County to Roseau County. Some wild oat populations may also have developed cross resistance to sethoxydim (Poast and Poast Plus).
Resistance of kochia to sulfonylurea (Ally, Amber, Express, Harmony Extra) and imazethapyr (Pursuit) has been reported in various locations of the Northern Plains, as well as trifluralin (Treflan) resistance in green foxtail. A primary cause of these and other examples of herbicide resistance is continuously using herbicide treatments with the same mode of action.
Growers can prevent resistance by rotating crops, using mechanical weed control practices with herbicide treatments, using tank mixes with multiple modes of action, and rotating herbicides with different modes of action. A good rule of thumb is to make no more than two consecutive applications of herbicides with the same mode of action against the same weed unless other effective control methods are included in your weed management plan.