VOLUME 22, NO. 15                                                                                                                                                                                August 14, 2008

GRAND FORKS COUNTY COST SHARE

The Grand Forks Weed Board will be offering cost share chemicals to registered landowners.  Chemicals will be Plateau, Tordon, Banvel, Milestone, and 2, 4-D.  For more information contact Kevin Bonham at 218-779-4709.  Chemicals will be available Monday, September 8^th through Friday, September 12, 2008 at the following address:

            Kevin Bonham
            1637 15^th Ave. NE
            (1/2 mile west of CR #5 and 32^nd Ave.)
            Grand Forks, ND 58201
            218-779-4709

UPDATED FUEL COST SPREADSHEET

Dwight Aakre, NDSU Farm Management Specialist, has updated the fuel cost spread sheet.  This spreadsheet calculates the additional cost of fuel for various field operations that should be added to the average custom rates.  The latest survey was 2007 and the approximate fuel price during that survey was $2.75 per gallon.  The fuel price per gallon is user input, so if prices listed do not go high enough, the user can change them.  The spreadsheet can be found on the farm management web page: www.ag.ndsu.nodak.edu/aginfo/farmmgmt/farmmgmt.htm.

STEELE COUNTY PLOT TOURS

Steele County Crop and Livestock Improvement Association and NDSU Extension Service will hold their research plot tours on Wednesday, August 27 starting at 4:30 pm.  The plots are located on county Road 23 east of Sharon (5 miles east from the curve).  The tour will include corn and soybean hybrid studies, two fungicide plots, and a seed treatment study by BASF.  Guests will include Tom Lilja, executive director of the ND Corn Utilization Council, and several NDSU crop researchers.  Door prizes will be given away and the tour will conclude with a supper sponsored by Steel County Crop Improvement Association.  The annual meeting of the Crop Improvement Association will be held in conjunction with the supper.  For more information contact Ayanava Majumdar at 701-789-0545.

CORN ROOTWORM MANAGEMENT

The following is an article form Patrick Beauzay, Research Specialist, NDSU Extension Entomology:

Late July through late August is the time when growers should monitor for corn rootworm to determine the potential economic injury in next year�s corn fields.  This article reviews basic corn rootworm identification, biology, causes of injury, field scouting methods, and control methods for corn rootworm.  Two species of corn rootworm beetles affect corn in North Dakota: western corn rootworm (Diabrotica virgifera virgifera) and northern corn rootworm (D.barberi).  Western corn rootworm adults are yellowish orange with three black stripes on the wing covers that do not extend all the way to the tips, while northern corn rootworm is a solid green in color.  Adults of both species are about 1/4 inch long. Larvae reach a mature length of about 1/4 inch and are creamy white in color.  One generation occurs each year and both species have similar life cycles.  Both species overwinter as eggs, which hatch in June over a period of a few weeks.  Larvae move to nearby corn roots where they begin feeding.  Larvae pass through three instars and pupate in early to mid-July. Pupation lasts for five to ten days depending on soil temperature. Adults emerge in late July and begin to reproduce. Females lay 300 to 400 eggs in the upper two to eight inches of the soil.  Corn rootworm injury is caused mainly by larval feeding on the root system.  Larvae feed on root hairs and later on main roots, which lessens the plant�s ability to take up water and nutrients.  This results in lower yield.  In heavily infested fields, root injury may be so severe that the plants lodge at ground level.  The plants are still alive and try to grow upright, which results in �gooseneck� plants.  Goose necked corn is difficult to combine and further yield loss results from not being able to harvest ears from these plants.  Adults, particularly northern corn rootworm adults, may cause injury by feeding on silks before pollination is complete.  This causes reduced seed set, which also lowers yield.  However, silk feeding by adults is usually not a problem.  Sampling for corn rootworm adults should be conducted from late July (after pollination is complete) through late August once a week over a three-week period.  This will allow the grower to determine the potential infestation in next year�s corn.  In continuous corn and first-year corn that will be planted to corn the next year, adult abundance can be determined by direct visual counts of corn rootworm adults on corn plants.  For direct visual counts in corn, sample the field in a �W� pattern.  Stop periodically and count the number of adults on the foliage and silks of two plants, and continue in this fashion until you have counted 40 sets of two plants per set.  Corn rootworm adults may be concentrated in �hot spots� in a field, so be sure to cover a large portion of the field using the �W� pattern.  After you have counted 40 sets of two plants per set, simply divide the total number of adults by 80 to obtain an average of adults per plant.  For continuous corn using the direct visual observation method, the economic threshold is 1 beetle per plant. For first-year corn using this method, the economic threshold is 0.5 beetles per plant. Be sure to sample fields once a week during August as peak adult emergence may not occur during the first sampling.  A common crop rotation in southeastern North Dakota is a corn/soybean rotation.  Soybean fields that will be planted to corn the next year can be monitored for corn rootworm adults during August by using yellow sticky traps.  Placement of sticky traps in soybean fields should be AT LEAST 100 feet away from any neighboring corn.  A minimum of four trap stations should be used, but use more traps in large fields (up to 10 total trapping stations).  At least two trap stations should be on a side of the field not adjacent to corn. Traps should be changed once every two weeks.  The average number of beetles per trap per day over the entire monitoring period provides an estimate of potential economic injury to corn the next year.  This monitoring method has not yet been studied in North Dakota.  Research from Illinois, Indiana, and Ohio suggests an economic threshold of 5 beetles per trap per day.  Sweep net sampling in soybeans for corn rootworm adults is not recommended, as daily weather conditions and beetle flight periods are too variable to give accurate estimates of beetle abundance.  Control of corn rootworm can be achieved by crop rotation, soil insecticides, and by planting transgenic Bt corn labeled for rootworm control.  Soil insecticides are typically applied at planting in a 7-inch T-band over the open furrow or directly in-furrow with the seed.  Be sure to read and follow insecticide labels.  Transgenic Bt corn is a convenient management tool in that it essentially contains a built-in insecticide that offers control of larvae.  Be sure to follow the refuge requirement to help prevent the development of Bt resistance in corn rootworm populations!  The refuge requirement for corn rootworm is 20% non-Bt corn planted within or directly adjacent to Bt corn.

SOYBEAN APHID UPDATE

Continue scouting for soybean aphids.  Soybean aphid populations have varied from field to field this year.  Aphid in-flight appear to be decreasing but they are still moving in and around the region.  Fields that were sprayed early may still be at risk due to aphid movement, impact of early spraying on natural predators, and good environmental conditions for aphid reproduction.

IRRIGATED VEGETABLE TOUR

Commercial vegetable production and the Devils Lake Irrigation Test Project will be featured on a Cando area tour scheduled for Wednesday, September 3.  The tour will begin at 11am on the Mike Johnston farm.  From the intersection of highways 281 and 17 go one mile east on 17, then � mile south.  Lunch will be sponsored by Ken Storm of KT Irrigation.  The tour will conclude at approximately 3pm.  There is no registration fee and the public is welcome to attend.  Cabbage and other vegetable crops as well as processing facilities will be viewed on the farms of Mike Johnston and Mike Parker, both Devils Lake Irrigation Project participants.  Speakers from NDSU include:  Dr. Harlene Hatterman-Valenti, Dr. David Hopkins, Mike Liane, and Rudy Radke.  Holly Mawy, Director of the Entrepreneurial Center for Horticulture in Bottineau will discuss activities at the center as well as the North Dakota Farmers Market.  For further information contact Mike Liane, 701-351-0726.