Crop rotation, often among corn, soybeans, and other crops, is one means for breaking costly pest cycles in the field. (Photo by Brett Hampton)

July 16, 2004

Bacterial diseases widespread

Bacterial diseaes of soybean and corn are much more common this year, due to several weeks of rain and below normal temperatures. Field scouts found bacterial blight of soybean (above) and holcus spot of corn (below).

Holcus spot of corn appears as small round to oval light tan to white lesions which have a light brown border on the leaves. In some instances the border is not evident and in most hybrids lesions will appear bleached white. Holcus lesions can be confused with para-quat drift and eyespot. Eyespot is a fungal disease of corn which has more evident margins on the lesions and usually will have a “halo” of chlorotic tissue around the lesions. The “halo” is not present with Holcus spot lesions.

Bacterial blight on soybean will appear as angular lesions, which begin as small yellow to brown spots on the leaves. The centers of the spots will turn a dark reddish-brown to black and dry out. A yellowish-green “halo” will appear around the edge of water soaked tissue that surrounds the lesions. Eventually the lesions will fall out of the leaf and the foliage will appear ragged.

Both of these diseases are favored by stormy conditions which provide wounds on the leaves for entry and wet conditions with milder temperatures. The optimum temperature for both is around 75^oF. Infections usually start in the lower portion of the canopy. Remember that these are associated with wounds, so in soybeans sometime the lesions are not in the lower leaves of the canopy which are more protected during stormy conditions.

These diseases should go away as temperatures heat up and move out of the optimum range for bacterium growth. If conditions remain cool, avoid any cultivations or other traffic in affected fields because equipment can track the disease through the field and worsen the condition. Fields with reduced tillage will tend to have more of these disease problems as the bacterium resides in the residue.

Recent precipitation has helped supplement some irrigation; however, fall rains are going to be needed to maintain crop growth to maturity, especially for those without an irrigation well. Although there has been some hail associated with the rain storms, most irrigated crops are looking good. Plant stands are somewhat variable in both density and crop height due to the extreme dry conditions during emergence that caused germination to be delayed in portions of the fields.

Acreage to be harvested for grain is estimated at 1.80 million acres, 20,000 acres less than last year. “After the near record yielding crop of a year ago, this season has turned into a real disappointment for many Nebraska wheat producers due to the continued drought conditions in western counties and a mid-May freeze which damaged the crop,” said Mark Harris, director of Nebraska Agricultural Statistics. Wheat harvest started the third week of June and has kept a near normal pace.

Oat production is forecast at 3.65 million bushels, down 44% from last year’s record yielding crop. The number of harvested acres -- 50,000 -- is down 44% but yields are similar to last year.

USDA Nebraska Agricultural Statistics Service

At this point in the season, you should be able to see aphids by scouting the undersides of the uppermost soybean plant leaves. When deciding whether to treat, check the forecast temperatures for the next week. Generally, soybean aphids prefer temperatures in the 70s and 80s. Given the right conditions, aphid populations will grow rapidly in a matter of days. Population growth would be expected to slow when temperatures reach the mid 90s, although beneficial insects would likely continue feeding.

“By attending the Soybean Management Field Days, growers will take home unbiased, research-based answers,” Glewen said.

Each day’s program will include a tour of demonstration plots, speakers, lunch and Q&A. Topics include: growing soybeans with higher oil/protein, putting more soybean dollars in your pocket, new and emerging disease and insect problems, and the secrets of making no-till work.

Presenters include university specialists, educators and industry consultants.

The field days begin at 9 a.m. and end at 2:30 p.m. at each site. Free registration is available the day of the event. Dates and locations are:

• Aug. 10 – Fairmont, Paul Bettger farm, go to intersection of U.S. Highways 6 and 81. Go half mile east on Highway 6 to Sixth Avenue. Follow Sixth Avenue (Main Street) south through Fairmont. Field site is just outside of Fairmont on the west side of the road.
• Aug. 11 - Stella, Steve Kean farm, located 7 miles north of Dawson or 11 miles south of Auburn on U.S. Highway 75. Or, from the intersection of Highways 75 and 62, go 2 miles east on Highway 62 and one-fourth mile south. Field site is on the west side of the road.
• Aug. 12 – Hooper, Vernon Brandert farm; from Fremont, from U.S. Highways 30 and 77, 7.25 miles north on Highway 77 to County Road L (just north of weigh station), 1 mile west on County Road L, and 1/2 mile north on County Road 21.
• Aug. 13 – Lindsay, Randy and Larry Sueper farm, from Lindsay, 2.5 miles east on U.S. Highway 91 to 400th Avenue, go 1.5 miles north on 400th Avenue and three-fourths mile east on 497th Street (blacktop road through St. Bernard). Field site is on east edge of town, south side of road.

For more information or to register, visit the 2004 Soybean Management Field Days Web site at http://ardc.unl.edu/soydays.htm, contact the Nebraska Soybean Board at (800) 852-BEAN or Glewen at (800) 529-8030. The field days are sponsored by the Nebraska Soybean Board and Cooperative Extension.

One of the meetings will be held from 9:30 a.m. to 2 p.m. Wednesday, July 28, at the Holiday Inn Express in Fremont. This meeting is jointly hosted and sponsored by the Nebraska Soybean Association and the American Soybean Association and conducted in cooperation with USDA. Additional sponsors include: BASF Corporation, Bayer Crop Science, Dow Agrosciences, John Deer, Spicam Agro USA, and Syngenta Crop Protection.

I encourage producers and anyone involved in commercial agricultural advising to attend this meeting. One of the featured speakers will be Glen Harman of USDA, who has many years of experience with soybean rust. Other speakers will include representatives of USDA’s Animal and Plant Inspection Serviceand other scientists and industry experts.

“With possible yield losses of 80% or even 90%, rust is one of the most pressing issues facing U.S. soybean farmers,” said ASA President Ron Heck, a producer from Perry, Iowa.

Topics will include: an overview of the disease and what government and industry are doing to address it; a Brazilian grower’s story of battling it; recommendations on detecting rust; application methods and equipment; and fungicide availability and efficacy.

Tom Dorn, Extension Educator in Lancaster County: Pastures are looking the best they have in five years. Small grains: Wheat harvest is essentially complete and oats for grain will be harvested soon. Corn: Outside of the storm-damaged area, both irrigated and dryland corn looks good. Most corn has tasseled and fields are pollinating now. Soybeans: Most soybean fields have closed in the canopy and are blooming. In a brief survey of a few fields in western Lancaster County on Monday, I found a very small number of soybean aphids. Hay: The frequent showers have made hay production a nightmare. Some alfalfa fields that should have been cut for the second time are in full bloom and beyond but the farmers have not been able to cut because of wet soil. Other fields have been windrowed but have been rained on several times and the hay is rotting in the windrow.

Del Hemsath, Extension Educator in Dakota, Dixon and Thurston counties: Heat units finally made it to this area of the state and are helping the corn development. Bacterial rot is appearing in corn, especially where hail occurred earlier in the year. Low numbers of soybean aphids are beginning to appear in spotty areas. There is still some second cutting alfalfa laying in the field because of untimely rains with regrowth is 4 to 6 inches high. Soybeans are looking better and beginning to have canopy closure on the narrow rows. Pastures look great at this time.

David Baltensperger, Extension Alternative Crops Breeder at the Panhandle REC: We’ve seen a dramatic shift to hot and dry conditions in the Panhandle — especially a shift to hot. This is rapidly speeding up wheat maturity and should end most of our rust problems. Wheat that was potentially going to sprout should be able to be harvested without additional problems. Until it is in the elevator and checked we will have limited idea on how much of the Panhandle has sprout problems, but it should not be increasing at this stage.

Andy Christiansen, Extension Educator in Hamilton County: We have had quite a bit of rain generally across the county and about the only irrigation that has occurred has been quite a few pivots made a round a month ago. Wheat harvest has been delayed by rain. Western bean cutworm has been above threshold in many fields throughout the county. I believe quite a few will treat this week. Soybean insects have been very minor so far this season.

Corn condition improved and rated 2% poor, 14% fair, 51% good, and 33% excellent, above last year and average. Irrigated fields rated 86% good and excellent while dryland fields rated 81%. This compares to 81% and 74%, respectively, a year ago. Silking was 18% complete, ahead of last year at 9% and average at 14%. A few fields in east central and southeast Nebraska had reached the dough stage.

Soybean condition rated 1% very poor, 3% poor, 19% fair, 58% good, and 19% excellent, above last year and average. Forty-four percent of the acreage had bloomed, about a week ahead of last year at 11% and average at 25%. Three percent had set pods, ahead of last year at zero, but the same as average.

Sorghum condition rated 1% very poor, 3% poor, 34% fair, 49% good, and 13% excellent, below last year but above average. Heading had not yet begun, although last year was at 1% with average rated at 2%.

Wheat was ripe on 77% of the acreage, a few days ahead of last year at 68% and average at 74%. Harvest progressed to 45% completed, ahead of last year at 38% but behind the 53% average. Sprout damage was being reported in a number of counties.

Oat condition rated 12% very poor, 12% poor, 25% fair, 37% good, and 14% excellent. Harvest was underway with 9% cut, behind last year at 17% and average at 23%.

Dry beans had bloomed on 6% of the acreage, behind last year at 20% and average at 14%. Condition improved and rated 11% poor, 25% fair, 53% good, and 11% excellent.

Alfalfa conditions rated 5% very poor, 15% poor, 21% fair, 44% good, and 15% excellent, below last year but above average. Second cutting activities were 48% harvested, behind last year at 50% and average at 56% Wild hay condition rated 15% very poor, 12% poor, 25% fair, 40% good, and 8% excellent.

Nebraska Agricultural Statistics Service

USDA Nebraska Agricultural Statistics Service

Planting conditions during April and May across much of the Corn Belt were near ideal. Above-normal temperatures and light rainfall allowed planting to progress well ahead of the normal pace. Similar conditions were experienced in the northern and central Great Plains. However, planting progress slowed after mid-May as heavy rains fell in many areas of the Corn Belt. Growers in Michigan, Ohio, and Wisconsin experienced the most rainfall which prevented them from planting some of their acres originally intended for corn.

The 2004 soybean planted area is estimated at 74.8 million acres, up 2% from last year. If realized, this will be the largest planted area on record and a rebound from the three-year decline in acreage. Area for harvest, at 73.7 million acres, is also up 2% from 2003. The planted area is down 602,000 acres from the March Prospective Plantings report. Area planted increased or was unchanged from last year in all States except Illinois, Iowa, Minnesota, South Dakota, and Wisconsin. Growers in Illinois and Iowa showed the largest decreases in soybeans planted from 2003, but showed comparable increases in acres planted to corn.

All wheat planted area is estimated at 59.9 million acres, down 3% from 2003. Harvested area is expected to total 50.7 million acres, down 4% from last year. The 2004 winter wheat planted area, at 43.5 million acres, is 3% below last year, but up fractionally from the previous estimate. Of this total, about 31.0 million acres are hard red winter wheat, 8.3 million acres soft red winter wheat, and 4.2 million acres white winter. Acreage planted to other spring wheat for 2004 is estimated at 13.7 million, down 1% from 2003. Of this total, about 12.9 million acres are hard red spring wheat. The Durum planted area for 2004 is estimated at 2.74 million acres, down 6% from last year.

Carefully controlled tests in midwestern and western states have shown that intensive conditioners reduced drying times around 10%, which translates into about two hours earlier baling. Two hours versus two days -- why the difference?

Much of it may be due to lack of maintenance of conventional rolls. Often, clearance on farmer's conditioning rolls is much greater than the recommended 1/16 to 3/32 of an inch. Many times it’s more than a quarter inch. Why does this happen?

Part of it is due to wear over time and loss of material from roll surfaces. Vibration also can cause settings to slip, widening the roll clearance. Since it can be difficult to check or adjust roll clearance, especially on older machines, over time the gap gets wider and wider until little conditioning occurs at all.

Take the time to check and adjust your conditioning rolls. Set them as close as recommended by the manufacturer. This may be a nuisance, but it’s one of the better ways to hasten hay dry-down while keeping your current system.

For most folks, the best choice will be a summer annual grass, such as sudangrass, sorghum-sudan hybrids, pearl millet, foxtail millet, forage sorghum or cane, and even corn. If any of these grasses are selected, though, be sure chinch bugs aren't a problem. They can be especially troublesome following wheat or when planting near a previous wheat field. If chinch bugs are numerous, an insecticide treatment may be needed. Solid-seeded soybeans also are an option, especially if chinch bugs or other factors limit the potential for success with summer annual grasses. With just a few more timely showers, all these options can produce a couple tons of good forage yet this year. All of these crops can be grazed or cut for hay, but I prefer pearl millet or sudangrass for grazing and the others for hay.

Summer annual grasses will be ready to graze about five weeks after planting, but growth will stop after a freeze or when cold nights occur in September. If you would be better off with high quality grazing during fall and early winter, plant oats or turnips in early August instead. Both are cheap to plant and produce a lot of high quality feed in a short time with just a few timely rains.

Most importantly, do not turn hungry animals into sudangrass or sorghum-sudan pastures. They may eat so rapidly that they could get an overdose of prussic acid.

Secondly, since the highest concentration of prussic acid is in new shoots, let the grass get a little growth on it before grazing to help dilute out the prussic acid. Begin grazing sudangrass at about 18 inches in height, but wait until sorghum-sudan hybrids are 20 to 24 inches tall before grazing because they usually contain a little more prussic acid. If you planted pearl millet there is no need for these grazing precautions because it does not contain prussic acid. So let your animals graze pearl millet when it reaches 12 to 15 inches tall.

Summer annual grasses respond best to a simple, rotational grazing system. Divide fields into three or more smaller paddocks of a size that permits your animals to finish grazing each paddock within 7 to 10 days. Graze plants down to about 8 or so inches of leafy stubble before moving to the next paddock. Repeat this procedure with all paddocks. If some grass gets too tall, either cut it for hay or rotate animals more quickly so grass doesn't head out.

A well-planned start, a good rotation and a little rain will give you good pasture from these grasses the rest of the summer.

Integrate red cedar control measures

Eastern redcedar can be a serious problem on grasslands where it competes very effectively with pasture species for light and nutrients, reducing forage production. Heavy tree infestation interferes with livestock handling too. These adverse effects often lower rental rates or sale prices of infested grassland. On many sites complete coverage by eastern redcedar can be expected, resulting in total loss of production.

Control measures should be initiated as soon as possible, both to improve effectiveness and reduce total costs. In most cases, a single control measure can’t provide long-term management of this species. However, if the control practices are integrated in a systematic manner, significant advances can be achieved. Control methods should be based on an integrated management approach, which includes a combination of manual, mechanical, cultural, biological and chemical methods.

Manual control involves pulling or digging trees. It can be very effective for small areas and is most efficient on trees up to 2 feet tall. Mechanical control methods such as cutting or mowing involve use of various hand held or motor-powered tools. Mowing of short trees can be also utilized as part of the regular cutting and haying process. The overall key to success in cutting or mowing is to cut the tree at the soil surface or below the lowest branches. Red cedar trees that are cut low should not regrow. In addition, if the goal is to just reduce overall number of trees and reduce further spreading (eg. management of wildlife habitat), it is recommended to cut only female trees (the trees that produce berry-like fruits).

Biological weed control or bio-control is the use of natural enemies to reduce weed populations to economically acceptable levels. In the case of red cedar control, goats can be utilized as an effective bio-control agents for trees that are up to 3 ft tall. Goats are known browsers, whose diet consists 75% of non-grassy species, which means they will not compete with your cattle for grass. They are also alternative tool for control of many noxious weeds, especially for leafy spurge. Keeping several goats at your pasture can help control many non-grassy species including red cedar trees.

Prescribed fire can be also used. This method is inexpensive and effective against smaller trees. However, its effectiveness declines as tree size increases. Adequate fine fuel (usually, last year’s dead grass) is necessary for satisfactory results. Safety also is a concern since many managers lack experience with fire and the equipment required to conduct fires.

Chemical control should be also considered. Herbicides should be viewed as just another tool in the integrated approach tool box. Herbicides can be used for both ‘individual-tree’ spraying and broadcast application.

Individual tree treatments Currently there are several herbicides suggested for individual tree treatments in spring or fall. Examples include Tordon 22K, Velpar-L and Spike 20P. Tordon 22K can be used as a spot gun application of soil around the tree before rainfall. Rainfall will help uptake the chemical. The recommended rate is about 1 cc (ml) per foot of tree height. Cost of Tordon 22K is about $85 per gallon. It would costs about $65 per acre plus labor ($15 /hour) to spray 1500 trees that are about 2 feet tall. Velpar-L can be also used through a spot gun in Spring at the rate of 4 cc’s (ml) per every inch of tree diameter. Cost of Velpar is about $65 per gallon. Spike 20P is another alternative but only in non-crop areas as a total vegetation control at the rate of 0.5 oz per every inch of stem diameter. Cost of Spike 20P is about $9 per pound of product.