The Weird Weather of Summer 2012

Drought impacts corn, beans, wheat and sugar beets across the state.

Published on: Aug 6, 2012

We've been inundated, and rightly so, with reports about Minnesota farmers dealing with drought in parts of the state and what various agencies and university specialists are doing to provide assistance.

We've assembled some of that information here for your perusal.

Spider mite outbreak
Two-spotted spider mites are making the most of this year's hot, dry weather, say entomologist Ken Ostlie and integrated pest management specialist Bruce Potter, University of Minnesota Extension.

For farmers and crop advisers not familiar with spider mites, the damage they cause may be mistaken for drought symptoms. Infestations usually begin on fields edges, particularly adjacent to cut grass or alfalfa.

The Weird Weather of Summer 2012
The Weird Weather of Summer 2012

If you see a discoloration of the lower leaves on your soybeans or corn, you need to get in the field and scout for mites. To do so:

1.Start at the field edge where symptoms occur.

2.Examine leaves from the bottom upwards. Look at the underside of leaves. Note yellow spots (stippling), webbing and how far up the plant the damage has progressed.

3.Tap damaged leaves over a white sheet of paper and look for mites with a hand lens or magnifying glass. They are very small—half the size of a soybean aphid nymph. 

4.If mite presence is verified, it's time to progress into the field. Move at least 100 feet into the field before making your first stop. Walk a "U" pattern, checking at least two plants at each of 20 locations.

5.Check fields every 4-5 days if drought persists.

Treatment is recommended only if damage and mites are detected throughout the field. Edge treatments are not effective since mites are usually spreading throughout the field before any visual symptoms are noticed.

For soybean, a general guideline is that if stippling reaches mid-canopy leaves, a treatment is likely necessary. For corn, the goal is simply to keep damage from reaching the ear leaf; treat when the lower one-fourth to one-third of the canopy shows damage and mites can be seen in the middle third of the canopy.

Spider mites live on the undersides of leaves and are more concentrated lower on the plant. If you decide to spray, canopy penetration is critical. Do not skimp on water—for ground applications, use 20 or more gallons per acre; for aerial applications, use 3 to 5 gallons. Evaluate control three to five days after spraying.

If you've decided that an infestation warrants spraying, don't hold up a spray waiting for rain. Instead, if rain is unlikely to occur before the spray dries, go ahead with the spray. Reducing spider mite pressure will allow the crop to take full advantage of any moisture from the rain.

If your field is infested with both spider mites and soybean aphids, base the treatment decision on the worst problem.

Prepare for higher forage prices
At the July 24 hay auction in Pipestone, supreme quality alfalfa hay brought a high of $260 per ton, while grass/alfalfa mixed hay brought a high of $200 per ton, reports Krishona Martinson, crops educator and equine specialist, U-Minnesota Extension. Grass hay was slightly lower at $180 per ton.

To prepare for higher prices, livestock owners should consider these tips:

•Keep in mind that quality forage should be the backbone of the livestock diet. For cattle producers, corn silage, alfalfa or grass haylage, and straw can be added to the diet. However, the drought has affected the supply and price of these feedstuffs as well. For horse owners, forage (in the form of hay or pasture) should comprise a minimum of two-thirds of their diet. Few forage alternatives exist for horses.

•If purchasing drought-stressed forage (hay products or corn silage), the forage should be tested for nitrates. Nitrates can accumulate in stems and stalks of drought-stressed plants. Once livestock consume the forage, nitrates turn into nitrites, which bind to red blood cells, preventing the cells from carrying oxygen to tissues. Two cases of nitrate toxicity have recently been reported in Wisconsin cattle herds. On a positive note, drought-affected alfalfa usually has a higher leaf/stem ration, resulting in better quality.

•If possible, consider adding hay storage to reduce the effects of seasonal price fluctuations. Hay is usually more affordable when purchased during the growing season compared to the winter months.

•If purchasing hay, buy it early. Waiting for later cuttings (which are usually higher in quality) puts livestock owners at risks of limited late-season supplies and higher prices. Having a good working relationship with a hay supplier can help ensure a consistent and reliable source of hay products and/or corn silage.  

•Plan in advance. Budget for the price increases in feedstuffs and re-evaluate how many livestock you can afford to feed. Unfortunately, increases in feedstuffs are not always balanced by higher prices for livestock products. 

•Finally, try and keep the hay type (grass or alfalfa) or forage product consistent in the diet or ration. Constantly changing hay types can lead to health problems, especially with horses, and can affect production outcomes in cattle.

Comments from the southeast and the north
Extension specialist Ryan Miller, Rochester, reports that crops are more variable than normal. He spent some time last week in southern Steele and Freeborn counties. He saw fields that were considerably drier south of Highway 30; reports were that crops were drier and worse as you headed into the southwestern part of the state.

In one Freeborn County field, he said early RM corn was dented and later RM corn was showing an occasional dent. Soybeans last week were at R4 or R5. Spider mites were present in the southern Steele and Freeborn areas. "Corn could be mature in 20 days if warm weather continues," he added, asking "Could we combine some corn before beans?"

Growing degree days are a solid 3 to 4 weeks ahead of normal.

He also noted that variable reports indicated that sweet corn yield was 10% to 50% less than normal in southern Steele and Freeborn counties.

Retired Extension specialist Russ Severson, Crookston, covers the region from Mahnomen to the Roseau-Hallock area. He reports that by end of last week, the wheat harvest about 75% done.

Yield is better than earlier thought, with 55 to 65 bushels per acre as quite common. Some fields have yields as low as 20 bushels per acre on last year's beet ground.

Soybean spider mites are more of a problem than aphids.

Pre-pile beet harvest is in about a week or so.

Soil moisture still is very dry and some soybeans, beets and corn show drought stress in the heat of day.

"Crops seem to be hanging in there on minimal rain," he adds.

Severson currently works with soybean and wheat growers association out of the Red Lake Falls office.

Estimating corn yields during drought
U-M Extension educator Liz Stahl says that a recent article by Peter Thomison, Ohio State University, discusses estimating yield in drought-stressed corn.

Since the grain fill period may be reduced when corn is under drought stress, the normal "fudge factors" used in equations to estimate yield may be off, she says.

Check out the article "Estimating Yield Losses in Drought-Damaged Corn Fields" (C.O.R.N Newsletter (July 31 - August 6, 2012) at http://corn.osu.edu/newsletters/2012/2012-24/#4 for further details.

"Estimates are just that—estimates," she says. "However, they can be useful for planning purposes and to help give you a better idea of what to expect at harvest time."

Also, U-M's Extension Drought website has many valuable resources to help you deal with drought-related issues: http://www.extension.umn.edu/extreme-weather/drought-fire/ (click on "Farm" for farm-related resources).

CRP acres open for grazing, haying
Additional Conservation Reserve Program acres have been authorized for emergency haying and grazing in Minnesota due to prevailing drought conditions.

The expanded authorization includes the following practices:
CP8A, Grass Waterway—Noneasement
CP23 and CP23A, Wetland Restorations
CP25, Rare and Declining Habitat
CP27 and CP28, Farmable Wetlands Pilot (FWP) Wetland and Buffer
CP37, Duck Nesting Habitat
CP41, FWP Flooded Prairie Wetlands.

Emergency haying and grazing of CRP is now open in 71 of the 87 Minnesota counties where the severity of the drought has at least reached the "D0" level, Abnormally Dry, according to the U.S. Drought Monitor as of July 19, 2012, or later.

To initiate emergency haying and grazing of CRP, producers must first contact their local FSA office to apply. Producers must sign a modified conservation plan to allow haying and grazing.  No more than 50% of a CRP field may be hayed, and haying must be completed by August 31, 2012. No more than 75% of a field may be grazed, and the grazing must end by September 30, 2012.  Haying or grazing cannot occur within 120 feet of a stream or other permanent water body, or on acres devoted to trees.

For more information, contact the Minnesota FSA State Office at 651-602-7702.

BWSR okays RIM acres for grazing, haying, too
The Board of Water and Soil Resources also authorized emergency haying and grazing of Reinvest in Minnesota acres for 70 counties affected by drought conditions.

Many RIM easements are enrolled jointly with a federal program, such as the Conservation Reserve Program or Wetland Reserve Program.

For these joint easements, BWSR will defer to federal guidelines, requiring landowners to comply with federal provisions.

For state RIM easements only, BWSR established the following policy:
•Landowners who are interested in emergency haying and grazing must contact their local soil and water conservation district office to file a plan amendment before haying or gazing RIM acres.
•At least 50% of each easement area will remain undisturbed for wildlife.
•Tree plantings, food plots, water control structures, wetland basins and stream banks shall be excluded.
•Where practical, mowing will begin in the center of the area to be harvested and commence inside out to allow wildlife escape routes.
•Haying/grazing will be limited to August 2 – September 30, 2012 to protect ground nesting wildlife.
•Haying/grazing grasses should be harvested no shorter than 6" in height to ensure regrowth.

Compiled by Paula Mohr