Crop & Pest Report
Populations of potato leafhoppers and spider mites are increasing in dry edible beans and soybeans in eastern North Dakota.
Scout for spider mites and corn leaf aphids in corn. Reports of corn leaf aphids have been reported in Benson and Cavalier Counties, and spider mites in Cass County. These corn insect pests also have been reported in neighboring states (South Dakota, Minnesota, Iowa).
IPM field scouts surveyed 73 wheat fields during the second week of July. The average growth stage of these fields was early milk, at least two weeks ahead of the average growth stage in 2011.
Maps detailing precipitation, temperature, and departure from normal corn and wheat accumulated growing degree days.
Field Days being held at various North Dakota sites in July are listed below.
With the hot and dry weather, grasshopper populations are increasing, especially in western North Dakota. Wheat fields in McKenzie County are reporting large numbers of grasshoppers resting on wheat heads.
White empty heads are being observed in cereal grain fields. These were likely caused by wheat stem maggot. A single maggot (larva) is responsible for causing the white head and can be found inside the stem just above the last node.
Banded sunflower moths and sunflower moths are being captured at higher numbers in pheromone traps at Mapleton, Cass County.
Early-planted soybean is now reaching the R1 growth stage in southeastern North Dakota. Although soybean aphids were detected rather early in eastern North Dakota, numbers remain low.
During the past few years we have had excessive rainfall prior to and during the growing season. One of the management strategies to reduce excess water stress on crops is to install subsurface tile drainage. This year we are experiencing a dry year.
For most regions of the state, the 2012 growing season started well, as the dry spring allowed for early planting and temperatures in May were nearly ideal for the development of high yield potential in the small grains.
IPM scouts looked at 38 wheat fields during the 4th of July week. The average growth stage for the wheat surveyed was at the end of flowering.
Goss’s wilt in corn was confirmed by the NDSU Plant Diagnostic Lab last week in a sample of corn leaves from Richland County. This disease was confirmed in five of six samples tested last year by the NDSU Plant Diagnostic Lab, and was independently confirmed in corn in 2011 by various seed corn companies.
Most years the small grain harvest, especially wheat, happens in mid-August. This week harvest will start probably the last full week of July- about 3 weeks early.
We are receiving many phone calls and e-mail messages about suspected herbicide-resistant weeds. After two herbicide applications in corn and soybean, it is quite evident that weeds are surviving various herbicides.
The first two pictures below indicate how field perimeters (corn) and other field margins (surface ditch in soybean field) should look at this time of the season and at harvest. The last two pictures indicate what field perimeters and other field margins (sloughs, surface ditches, low spots, salt pockets, IDC pockets) should NOT look like once plants begin to flower and at harvest.
Now that most herbicide applications have been applied for the season and preharvest glyphosate-applications will soon be made to spring wheat, it is time to scout fields for surviving weeds.
A Weed Science Field Day will be held on July 25, 2012 starting at 10:30 AM at Moorhead, MN (From intersection of Hwy. 75 & 15th Ave. North in Moorhead go west for about 0.5 mile to 14th St. & turn right (north on a gravel driveway by Clay County Dept. of Motor Vehicle.
Information from the south-central region of North Dakota.
Information from the southwest region of North Dakota.