Crop & Pest Report

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North Central ND (07/12/18)

Information from the North Central region of North Dakota

Some parts of the region continue to see decent amounts of rainfall.  Minot received about 0.45”, Bottineau 0.81”, Crosby 0.50”, Garrison 1.26”, and Rugby 0.57” of precipitation.  Soil temperatures (bare) appear to be holding steady at most NDAWN stations in the North Central region (NCREC/Minot - 83˚F, Bottineau - 75˚F; Garrison - 77˚F; Rugby - 75˚F). 

Continue to scout for populations of grasshoppers in the area as some growers are spraying for control, however, it is important to keep the action threshold in mind before making an insecticide application.  The ‘threatening’ rating is considered the action threshold and is advised whenever 50-75 nymphs per square yard are being observed in adjacent non-crop areas or 30-45 nymphs per square yard within the field. Growers can use a 15-inch diameter sweep net, taking four 180 degree sweeps to equal a square yard estimate. Always inspect ditches and field edges for nymphs.                                                                                

For small grain aphids (i.e. Greenbug, Bird Cherry Oat Aphid, and English Grain Aphid), the treatment threshold is 85% of stems with more than one aphid present or 12-15 aphids per stem, prior to complete heading.  Populations above the threshold could result in economic injury.  Additionally, aphids are being reported in pulse crops in Ward County.  Again, consider economic threshold before spraying.  Scouting should be completed by examining the number of aphid per plant tip when 50-75% of the crop is flowering.  Check at least five 8-inch plant tips from four different locations in the field.  Calculations should be taken by determining an average of the four locations scouted.  In peas, economic thresholds can vary depending on crop value, potential seed weight, precipitation, and heat stress.  As an example, the economic threshold for peas valued at $5.71 per bushel (and an average control cost of $6.73-9.25 per acre) is 2-3 aphids per 8-inch plant tips or 9-12 aphids per sweep using a 15-inch diameter net at flowering.  For chickpea, there is no recommended threshold for aphids. 

Wheat Midge continues to be detected in traps across the region with numbers now falling from a peak 10 days ago.  However, scouting should continue.  Please refer to the Crop & Pest report from 2 weeks ago for more information.

 

TJ Prochaska

Extension Cropping Systems Specialist

NDSU North Central Research Extension Center

This site is supported in part by the Crop Protection and Pest Management Program [grant no. 2017-70006-27144/accession 1013592] from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed are those of the website author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.

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