NDSU Crop and Pest Report

Plant Science

ISSUE 2  May 9, 2002



Statewide average starting fieldwork was April 25, while the normal starting date is April 15. Some seeding was accomplished in many regions of the state but very little in some east central, eastern and northern regions. Thus far looking back in history, the North Dakota Agricultural Statistics Service - USDA, reported 1979 (twenty three years ago) was a wet spring with below average temperatures and was the latest start on May 13, in recent times.

Checking back however, yields were fairly good that year, as favorable weather followed and good soil moisture was present statewide to help crops reach above average potential.

2002 could be a similar year if some sunshine and warm weather soon come our way.

Here are the state-wide results of that late year compared to a recent 5 year average.




(Late year)

(5 yr. avg.)


26.5 bu

31.2 bu

Durum Wheat

26.0 bu

26.4 bu


44.0 bu

53.6 bu


46.0 bu

51.6 bu


13.0 bu

19.5 bu


16.1 ton

20.4 ton


160 cwt

228 cwt


27.0 bu

31.7 bu

Dry Edible Beans

13.5 cwt

13.7 cwt

Grain Corn

76.0 bu

105 bu

Silage Corn

6.7 ton

8.6 ton

Sunflower (all)

1357 lbs

1341 lbs


1050 lbs

1330 lbs



Wheat and Barley

Studies on spring barley in several parts of Minnesota and Langdon showed yield losses of 0.7 bushels per acre per day for each day the crop was planted after the optimum date.

Studies in Minnesota on hard red spring wheat showed a yield loss of one percent per day by delaying seeding beyond the optimum date.

This amounted to 0.6 bushels per acre per day yield losses. Cando durum yield loss in 1984 and 1985 at Langdon averaged 0.7 bu per day when seeding was delayed from late April to early June. Typically most severe yield losses occur when planting occurs after mid May.


Higher corn grain yields will be obtained with early plantings. In most regions this means seeding between

the last week of April and May 10. Early planting is recommended because risk of fall frost damage is greater with each day planting is delayed. The risk increases rapidly after May 20 and seeding corn for grain production is not recommended after June 1. Select and plant early-maturing, short-season hybrids when planting is delayed because of wet, cold planting conditions. Date of planting studies have been conducted at Oakes, Casselton and Fargo, ND. In these studies approximately one bushel per day was lost by delay of planting during the month of May. In this northern corn growing area yield losses accumulate rapidly, from 7 percent or more through May 20, 13 percent or more to May 25, and 24 percent or more to June 1. For silage corn, later plantings can be tolerated without great yield losses but can result in frosted corn, thus lowering quality of forage.


As we get later into the planting season, its suggested that canola (a heat sensitive crop) be seeded first and then complete small grains, sunflower and beans planting later. Research has shown that canola yields drop quickly if planted late.

For canola planted acreage south of U.S. Highway 2, its suggested canola always be planted before small grains and, if possible, before May 15. For the NE and areas and growing areas north of Highway 2, canola should be planted no later than May 25.

The optimum planting date for canola is late April to mid May. Canola yields have decreased sharply across most of the state (except the northeast) when canola is planted beyond mid-May.

Canola is more sensitive to heat stress than all small grains, flax, and other cool season broadleaf crops, thus the importance to seed canola early. Canola is also quite tolerant to spring frosts.


Seed in late April to early May. Yield decreases approximately 2 bu/week for each delay in seeding. More severe yield decline occurs when planting after May 15 in northern North Dakota.

Early June planted flax was 8 bu/A less than early May planted flax at Minot averaged over 9 years. These data suggest that all flax should be planted between late April to May 15 to ensure maximum yield potential. Good seedbed preparation, adequate shallow seed placement to moisture, weed control and fertility management also will contribute to high flax yields. Yield goals of 30+ bu/A are not unrealistic for well managed flax production.


With soybeans, yield losses due to late planting of adapted varieties in the Red River Valley are usually negligible until May 20. Depending on weather, possible yield loss can be approximately 13 percent from May 26 until June 9, when late planting losses can be near 25 percent. Soybeans planted as late as mid June can have a 40 percent or more yield loss compared to more timely plantings.

Dry Edible Beans

May 12-31 is the planting window for dry edible beans in North Dakota and Minnesota. Beans will not germinate if planted in soils cooler than 51-52 F. Soil temperatures of 55 F or higher is most ideal for rapid germination and emergence. Plant shallow if planting early. One to two inches deep is ideal under most conditions.


May 15 to 25 in most years is the most ideal time to plant sunflowers in North Dakota. For more northern areas (North of highway 2) growers should consider May 10-20, while south of that line May 20-30 is most appropriate for full season hybrids. Generally its suggested that confectionary and NuSun hybrids be planted earlier than the conventional oilseed hybrids. Early planting of both confectionary and NuSun will aid in improved quality. When adverse spring planting weather forces northern location growers to plant into early June, then early maturing hybrids should be selected. Many of these early maturing hybrids can be planted up until June 10. Later plantings than June 10 would be risky in most seasons.



Recent phone calls indicate many producers are still struggling with planting decisions including the use of bin run seed. Percent germination, diseased kernels, presence of weed seed, purity, and inert material are factors that impact crop stand and ultimately production and should be evaluated before using bin run seed. Germination of seed used for planting should be high. Acceptable germination is:













To determine germination simply lay 200, or more if inclined, randomly selected seeds from your bin sample on heavy duty paper towels, role the towels up and secure the role with paper clips, wet the towel and place it in a bread bag. Then place it in a location that remains about 50 to 60E F. After two days count the germinated seed and divide by the total tested, and you have percent germination.

Discolored black, pink, grayish and shriveled seeds are general indications of disease. A diseased kernel is less likely to germinate properly and when it does seedling disease may occur. Seed from a field infected with Fusarium head blight when replanted is likely to develop seedling blight resulting in seedling mortality and stand loss.

Shriveled and low test weight seed may germinate well but the vigor of the young seedling is often considerably less than from plump seed. These weak seedlings are less competitive with weeds and less likely to recover from early season moisture or temperature stress.

Grain mechanically dried at temperatures over 110E F is probably not suitable for seed. Drying at high temperatures injures the germ.

Whenever bin run seed is used and having it conditioned or cleaned will eliminate many of the potential problems previously described and will pay dividends. Conditioning eliminates light kernels which includes most diseased kernels, weed seed and inert material.



Cold soil conditions this spring brings questions on corn seeding emergence problems. Corn should begin emerging after about 100 to 125 GDD’s have accumulated following planting. This can be anywhere from one to three weeks after planting depending on the temperature. Here’s a list of a few common things to look for if you encounter an emergence problem in corn this May.

Duane R. Berglund
Extension Agronomist

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