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Published June 06, 2011, 05:00 AM

NDSU experts offer late planting advice

FARGO, N.D. — Late planting issues in soybeans, small grains and sugar beets headline North Dakota State University’s June 2 crop and pest report. Farmers shouldn’t panic and replant soybeans without taking stand counts and first making sure that any reason for a poor stand is corrected, says Hans Kandel, extension broadleaf crop agronomist.

By: Mikkel Pates, Agweek

FARGO, N.D. — Late planting issues in soybeans, small grains and sugar beets headline North Dakota State University’s June 2 crop and pest report.

Farmers shouldn’t panic and replant soybeans without taking stand counts and first making sure that any reason for a poor stand is corrected, says Hans Kandel, extension broadleaf crop agronomist.

Factors: Water-saturated soil, shallow seeding or plugged planter. Evaluate uniformity of the remaining stand and yield potential, as well as weather forecast and timeliness and cost of replanting. Row gaps of more than 2 feet may lead to yield reductions. Soybean populations can vary 50 percent from recommended levels without affecting yields, “as long as missing gaps are not too large and weeds are controlled,” Kandel says.

Soybean planting information: www.soybeans.umn.edu.

Small grain planting is looking “really late,” says Joel Ransom, small grains specialist, and there are no recent studies to predict indicate the yield impacts. The general rule of thumb is that for every day of delayed planting “beyond the optimum planting date,” yield potential declines differently for various crops: wheat, 1.5 percent; barley, 1.7 percent; and oats, 1.2 percent.

Manitoba studies predict 1.3 percent yield losses: gov.mb.ca/agriculture/

crops.

“Assuming that planting can resume during the second week in June, and using a 1.3 percent yield loss per day delay, estimated yields for small grains crops would be about 55 percent of the optimum for the northern tier of the state and only 27 percent of the optimum in the southern tier of the state,” Ransom says.

Small grains planted in northern North Dakota by June 21 normally would mature by the first week of September, Ransom says, noting that’s only a week ahead of the first frost in that part of the state. Farmers should adjust nitrogen to match yield potential for late planting.

Late-planting sugar beets still is possible. Research from Prosper, N.D., in 2009 and ’10 showed yields of 20 tons per acre when planted June 21 and harvested Sept. 28.

“When planting late, aim for higher populations of 175 to 225 plants per 100 feet of row at the six-leaf stage to get maximum yield and higher sucrose content,” says Mohamed Khan, sugar beet specialist. High populations will compensate for threats from root diseases, other pests and wind, and inability to replant.

Higher populations also use the full rate of nitrogen applied earlier, Khan says. Information: Mohamed.khan@ndsu.edu

Prominent pests

Other topics for the week:

-- Soybean switches and cyst nematodes. Soybean cyst nematode is confirmed in six North Dakota counties, so keep this in mind if thinking about switching to soybeans from other crops, says Sam Markell, plant pathologist.

“A resistant variety will pay dividends twice,” Markell says, “by increasing yield in the current year and by limiting a spike in egg counts that will impact yield in future years.”

Farmers who already use resistant varieties should switch the source of resistance. There is variability within resistance sources: “Variety ‘X’ with PI88788 may act differently than variety ‘Y’ with PI88788,” he says. Information: Samuel.markell@ndsu.edu.

-- Potato blightline: Syngenta Crop Protection is sponsoring a blightline for the 17th year. It uses local weather stations to forecast occurrence of the disease, using NDAWN and the WISDOM computer program. NDSU and University of Minnesota plant pathologists Gary Secor and Neil Gudmostad will make recommendations Mondays, Wednesdays and Fridays through mid-September. This year for the first time, sentinel plots for early detection are being coordinated by Daune Preston, retired extension potato specialist. Information: 888-482-7286 or www.ndawn.ndsu.nodak.edu and click the potatoes drop down box. Or text message BLIGHTND to 97063, or go to Twitter and follow @SyngentaSpuds.

Weather and weeds

Cool weather and glyphosate activity: With cool conditions, farmers should apply the “highest single application rate of glyphosate to Roundup Ready crops, especially if lamb's-quarters and wild buckwheat are present,” says Jeff Stachler, NDSU and University of Minnesota sugar beet agronomist.

“In addition to glyphosate, include a quality nonionic surfactant (NIS) at 0.25 to 1 percent (volume to volume), depending upon the glyphosate formation. Another way to improve weed control under these conditions is to mix other herbicides with glyphosate. Apply “full-labeled” rates of the tank mix partner to small 1- to 3-inch weeds, “unless you are confident a lower rate will be effective,” Stachler says.

Use the least antagonistic adjuvant to glyphosate. Tank-mixing is “definitely the best option” if “a reduction of glyphosate activity has been observed over time” because of resistance, Stachler says. Information.

--- Callisto on corn, by air in North Dakota: The North Dakota Department of Agriculture has approved the use of Callisto herbicide to control broadleaf weeds in corn through Aug. 15. Apply Callisto at 3 fluid ounces per acre, when wind speed is less than 10 miles per hour, and allowing a 50-foot buffer between sensitive plant species.

This year, the region is two weeks behind for most “degree day” accumulations for calculating insect pest thresholds. Insect growth only occurs within a range of temperatures, with minimum temperatures required, and each species has its own thresholds. For example, degree days are useful in predicting alfalfa weevil and grasshoppers, but the predictions only are an estimate. To calculate the degree days, go to the insect section online.

Alfalfa weevil hatch is occurring in the south-central and southeast counties of North Dakota and in the northern Red River Valley. Sioux, Emmons, Richland, Cass and Traill counties could see first and second-instar larvae. Grasshopper hatch has occurred in northeast, north-central, south-central and western counties, but heavy rains and drowning portends “potentially low survival,” says Janet Knodel, extension service entomologist.

Sugar beet root maggot activity so far has been low because of cool weather, as flies are just starting to emerge, says Mark Boetel, sugar beet entomologist.

As of May 30, only a “two total flies” have been captured in St. Thomas, N.D., and Baker, Minn. Peak fly activity in current-year beets most likely is on the first calm or light-wind day to reach 80 degrees Fahrenheit after 600 air degree days are accumulated, but activity can accelerate quickly after a “major increase” in air temperatures. Growers in infestation areas should “consider applying a post emergence insecticide, especially if a low- or moderate rate of an at-plant soil insecticide was applied,” Boetel says.

“Growers preferring granular products should apply them immediately or as soon as soil moisture conditions allow.”

Information.

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