NDSU Extension - Ramsey County


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May 3, 2010 Ag Column


It is really good to be back in North Dakota.  I had traveled to Washington D.C. last week.  I was chosen for an expense paid trip, to attend a Public Issues Leadership Development training, in Washington D.C.  It was a very memorable trip as I had never been to D.C. but thank goodness for the wide open spaces of North Dakota.  That kind of living is not my way of life.

Springs work is upon us with many varying difficulties facing producers.  The big question is “how do I get to my field this spring and how much of the field is left to plant”.  Our neighbors are in much better shape in the northeastern part of the county.  One being elevation and the other being much less precipitation during the winter season.  The fields were much drier in the northeastern part of the county.  With that being said there are still issues with 2009 Pre-vent plant acres.  Those acres went into the winter season unusually wet and will continue to haunt the farmers all spring season long.

Below is the latest information about our Winter wheat crop.  Wheat Streak Mosaic is once again a culprit in the north central part of the state.  Be watchful and vigilant about monitoring your winter wheat crop and also any new growth spring wheat growing, this spring.  Most winter wheat fields I have looked at, to this point, are in the 3-5 leaf stage and looking very good yet.



Wheat streak mosaic virus (WSMV) has been detected in early planted winter wheat and concern has arisen about this disease in volunteer

spring wheat.  Several scenarios are of concern:


SPRING WHEAT VOLUNTEERS:  Considerable areas of spring wheat volunteers that survived the winter are being observed across the state.  Though very unusual, it appears that spring wheat germinated in the fall, mostly in the warm November, and survived under the good

snow cover that came in December.     NO symptoms of WSMV or the presence of wheat curl mites were found in examination of spring

wheat volunteers from Cass, Richland and central North Dakota counties.  Most spring wheat volunteers may have germinated late enough to have broken the green bridge necessary for survival of the wheat curl mite, the transmitter of WSMV.  Although no evidence of disease has been found in these volunteers, they should be destroyed prior to planting another wheat crop, because of herbicide timing and harvest concerns.


WINTER WHEAT AND WSMV: Symptoms of WSMV have been observed in early planted winter wheat (Sept. 5) by Area Extension Specialist Dan Waldstein, in the North Central region of North Dakota.  These fields were most likely infected last fall and the warm weather this

spring has increased mite development and virus spread.  Later planted winter wheat (Sept. 25) in the same area appears symptomless and healthy at this time.


Growers with symptomatic winter wheat still have time to destroy these crops and plant another crop.  Can mites from these infected crops move into adjacent winter wheat or spring wheat crops, even after herbicide treatment to destroy infected plants?  Potentially, yes.  Spraying glyphosate on an already infected crop stimulates mites to seek a new, healthy crop.  The risk of mite dispersal and

virus spread from an infected field tends to follow an oval-shaped pattern according to prevailing winds. Research in Nebraska has

suggested possible movement of up to one to two miles, depending on mite numbers in source fields.


Distance of movement depends on several actors:  how severe the disease is in the source field and how big the mite population; the temperature (higher temperatures favor more rapid reproduction of mite and mite movement, and stresses crops); and rainfall (lack of rain increases mite movement and puts more stress on remaining crops).  The best scenario for adjacent crops would be cooler temperatures and good rainfall.



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