North Central ND (8/25/11)

Wheat Streak Mosaic Threat for Early Planted Winter Wheat:

We expect winter wheat planting to be much greater this season especially if the drier weather continues.  We are optimistic since, for the first time in many months, the NOAA forecast for the month of September is for average temperatures and average precipitation.  Our concern with wheat streak mosaic virus is that producers will try to plant in late August which will put them at a much higher risk for wheat streak mosaic virus outbreaks.  The table below reviews risk factors for wheat streak mosaic virus.  For more information on wsmv please see: http://www.ag.ndsu.edu/pubs/plantsci/smgrains/pp646.pdf. 

Soybean Aphids on the Rise:

Soybeans are in the beginning pod (R3) to beginning seed (R5) stage.  Soybean aphids are prevalent in the area and have been found in all scouted fields.  There was an average of 193 aphids per plant with about half the fields over the economic threshold of 250 aphids/plant.   When 250 aphids per plant are found on a total of 20 soybean plants (4 areas of the field, 5 plants per area), an insecticide application is recommended.  Early pod (R3) is a good insecticide timing for aphid control with a range of early bloom (R1) to beginning seed (R5).  Once soybeans are in the full seed stage (R6) it is generally not economical to spray for aphids.   

Banded Sunflower Moths a Problem in some Fields:

Sunflowers in the area are in the R4 to R6 stage.  We have observed large numbers of banded sunflower moth larvae (more than 20/head) in some fields in the area.  Most fields are too late to get good control of this pest with an insecticide application.  Early flowering (R5.1) is the best timing for managing banded sunflower moth and several other key insect pests of sunflower.  It is generally not possible to control all insect pests in sunflower with one insecticide application.

Trap Catches:

Daniel Waldstein - Crop Protection Specialist

North Central Research Ext. Center, Minot