Warmer days this week pushed corn development toward maturity. (Photo by Brett Hampton)

September 3, 2004

Soybean aphids linger past expected demise

Since soybean aphids were mostly gone by late August 2003, this may indicate that plant maturity has a strong influence on how long aphids will stay. Recent cooler weather with little rainfall has been ideal for aphid buildup.

Many fields had not reached potential economic threshold levels until last week. This means that up until last week, those fields had probably not incurred any yield damage from the aphids. Now, as the beans mature and aphid populations should (we hope) begin declining, it is a very difficult decision regarding treating a field with insecticide. If fields are still in the R5 stage and aphids number 1000 per plant or more, an economic return is still possible but not guaranteed. Either way, the yield effects of treating or not treating will likely not have a major impact this late in the year.

Irrigated beans in the R6 stage likely will not receive a yield response from a treatment at this time and it is highly questionable whether dryland beans (even those under stress) will benefit. Much more information needs to be gathered in Nebraska since these aphids do not act quite the same as in other areas of the soybean belt. Hopefully growers who treated fields have left untreated areas to take yield checks so we will be able to refine our economic thresholds in the coming years.

While production, including seed production, was affected, it does not appear that seed quality for 2005 will be diminished. There’s been a thorough clean out of problem seed to achieve a high quality seed lot, said Steve Knox, manager of the Nebraska Crop Improvement Association. In wheat seed they’ve tested for certification average germination has been 93%, well above the 85% germination required for certified seed.

That’s a good sign for producers in the midst of ordering and planting wheat seed for 2005.

Seed selection While producers can’t control the weather or continuing drought, they can select seed to address potential yield and pest problems. With the “designer seeds” currently available to address a variety of production systems, growers can do a little research and select those seeds best suited to a particular field and farming system, said Knox. He recommends selecting wheat seed that is certified and well suited to the field’s soil and moisture conditions, expected disease pressure, and the farming operation. Producers should also consider treating their seed. On-farm wheat trials have shown that buying treated seed or treating it on-farm will pay benefits, especially this year, said Bob Klein, Extension cropping systems specialist.

When selecting seed, there is no single “perfect” variety, but selecting several complementary varieties can help balance potential weaknesses in one variety with the strengths of another variety. This compensation improves the opportunity for yield stability and profitability of the entire wheat production system.

The 2004 Fall Seed Guide, written by UNL Extension crop specialists, recommends four steps for balancing wheat seed selections to reduce risk while trying to achieve maximum yields:

1. Identify your workhorse variety -- one with reliable and proven yield records.
2. Complement production needs and limits. Select varieties with qualities matched to your production system and pest pressures.
3. Complement with a range of maturities. Select varieties that mature both before and after your workhorse to allow for non-normal years.
4. Complement with different genetics. Select varieties with 50% or less similar parentage to the workhorse variety and to each other. Varieties with similar genetic backgrounds often can be susceptible to the same disease and production risks.

It’s as simple as that, although that’s really not the “big picture” for producers who receive the benefits of years of research and development when they buy PVP seed. The Plant Variety Protection (PVP) Act requires that protected seed not be sold except through an authorized dealer. Seed saved from last year’s PVP crop can only be planted by the producer who originally purchased it. That means you can’t cash in on the hard work of the company who developed the seed, even to help a neighbor running short of seed.

It can take up to 10 years to develop an enhanced seed line and companies will be less interested in pursuing this work if they can’t get a return for their investment, said Steve Knox, manager of the Nebraska Crop Improvement Association. He said to expect companies and agencies to become more aggressive about reporting and prosecuting infringements.

Contact the Department of Agriculture at 402-471-2394 for more information about your rights and responsibilities. The department is responsible for enforcing the PVP Act.

Nebraska conditions range from severe drought in the west to dry or normal in the east, according to the National Drought Monitor, a product of the Drought Mitigation Center at the University of Nebraska and USDA.

This year some corn is tipping back due to the cooler conditions and yields will be affected. Tipping back reduces the number of kernels per ear. A reduction from 18 to 16 rows of kernels per ear will result in an 11% reduction in kernel numbers per ear. Ears that tip back one-half to three-quarters of an inch also will have an 11% reduction in kernels per ear.

”This tip back would amount to three to four kernels per row on an ear,” Elmore said. “I would not be surprised to see irrigated yields up to 10% less than those we saw last year in south central Nebraska. Yields, though, will still range above average because this was such a great production year.”

Delroy Hemsath, Extension educator based in Dakota, Dixon, and Thurston counties: The cool conditions have delayed corn development. We need about 800 more GDDs to reach maturity. That seems rather difficult to acheive considering the long range forecast. It has not rained here for five weeks and the crop has pretty well mined out any moisture and some fields are beginning to show moisture stress. The impact of tillage is notable compared to reduced till fields where there was more moisture longer.

Soybeans on the hills are actually turning yellow, likely due to a lack of water and the recent hot temperatures. In addition, these areas will be the first to mature because of poorer soils. Disease also could have an impact. Corn silage is being harvested for the feedlots. Alfalfa harvest is being completed and the regrowth is going to be rather poor because of the lack of water. Soybean aphids are still present in some fields but they aren’t expected to have much impact on soybean yield based on the development stage.

USDA Nebraska Agricultural Statistics Service: As of Sunday, August 29, corn condition declined and rated 2% very poor, 6% poor, 21% fair, 45% good, and 26% excellent, above last year and average. Irrigated fields rated 80% good and excellent while dryland fields were 55%. This compares to 76% and 10%, respectively, a year ago. Ninety-two percent of the acreage had reached the dough stage.

Soybean condition declined and rated 3% very poor, 11% poor, 27% fair, 46% good, and 13% excellent, still well above last year and average. Fourteen percent of the acreage was turning color, ahead of last year at 12% but behind average at 20%.

Sorghum condition declined and rated 2% very poor, 11% poor, 41% fair, 39% good, and 7% excellent, still well above last year and average.

Keep that cool water coming Soybeans may seem like they are shutting down when they start turning yellow, but they still need about two inches of water to reach maturity.

By this point in the season in many years, corn irrigation may be winding down or ending, while soybean irrigation should likely still be underway for several weeks. Remember that the peak moisture needs for soybean usually follow those of corn by about three weeks.

Most of the soybean crop’s water needs are during pod fill. To achieve the greatest yield, irrigation should be scheduled to meet this need. Often producers are surprised at how many inches of water are needed to finish out the soybean crop. Shutting off too early reduces bean size, greatly reducing yield. Use this worksheet to determine timing of the last irrigation.

Scheduling the last irrigation

In many areas of the state corn farmers are in the midst of picking up pipe or eagerly preparing for the last irrigation. In southeast Nebraska, however, where rains have been limited or anywhere soybeans were planted late, irrigation may need to continue.

Determining when to apply the last irrigation for the season is an important water management decision for any crop. While shutting off too early could potentially reduce yield, running later than necessary reduces room for storing off-season precipitation, increases the potential for leaching nitrogen, and adds to production costs. Balancing between the two requires knowledge of how much water is available in the root zone and how much more water the crop will need to reach physiological maturity.

Following are some tips on preparing grain bins and equipment to help you maintain all the value you put in storage. Most farmers with on-farm grain drying systems will begin harvest when grain moisture content is in the low 20s. There is some risk in binning high moisture grain. A bin of 21% moisture corn with a starting temperature of 75^oF, can lose a market grade in only three days if the aeration system breaks down. To reduce the risk of a breakdown after you have filled the bin, always check electrical systems for corroded connections and frayed wiring before harvest. Mice like to nest inside electrical boxes where they are safe from predators. They will strip insulation from wires for nesting material and their urine causes corrosion. While inspecting control boxes, be sure to seal any openings where mice could get in.

Alfalfa needs about six weeks of uninterrupted fall growth to become fully winterized. This winterterizing generally begins about three weeks before the average date of first frost. The last harvest can occur anytime before or after winterizing; however, harvest during the winterizing process can be risky, depending on the level of crop stress.

When determining when to take the last irrigation, first cosinder the number of cuts already taken. Fields cut four or five times are more susceptible to winter injury than fields cut three times or less. Also, young stands of winterhardy, disease resistant varieties are less stressed and can be harvested during winterizing with less risk than older stands of disease susceptible varieties that are only moderately winter hardy.

Also consider your need for extra alfalfa or its value as a cash crop. Dairy hay is priced high, so if you cut dairy hay from this final harvest it may be worth the risk of lowering next year’s yield. But, stock cow or grinding hay appears plentiful and reasonably priced. So it may be better to buy rather than risk another cutting. And remember, you can cut after winterizing with less risk.

Harvesting alfalfa during its winterizing period is risky, but by reducing total stress, you can control that risk.

Alfalfa grows best in soils with a neutral pH of about 7. When soils are acid, with pH of 6.2 or lower, alfalfa will not grow as well. At a low pH, alfalfa roots are less able to absorb nutrients from soil. The root nodules that convert nitrogen from the air into a form that plants can more readily use can’t work as efficiently in an acid soil.

Most sandy, low organic matter soils as well as heavier ground that has been tilled and fertilized with nitrogen for many years have become acid. These soils, which may have a pH as low as 5-5.5, need lime to rectify this problem. It takes time for lime to neutralize much acidity so I recommend applying lime at least four months before planting. That means that if you expect to seed a new field of alfalfa next spring, lime needs to be applied this fall so that it has time to work. The application is an investment, but is less costly than a stand failure or several years of low alfalfa yields.

Keeping the soil moist in fall and winter offers some advantages and can help limit winter desiccation, the most common cause of winter kill. Cold, dry winter winds dry out the soil and plant roots in that soil. When you have moisture in the soil as winter begins, less drying injury will occur. Of course, it also is nice to already have some moisture ready to support next spring’s growth.

So, how do you balance too much with too little irrigation? Ideally, seek to have four to five inches of moisture in your soil by Labor Day so that it’s available for regrowth after your late August or early September harvest. Then let the plants dry down naturally until winterizing is complete in mid-October or plant tops are fully killed by a hard freeze. Then, if soils are dry, add up to another three inches of water for extra protection from winter drying.

In fields where soils are very tight and absorb water slowly, you might even exceed this three-inch limit by continuing to irrigate until freeze-up to build soil water reserves for next year.

“Many alfalfa fields have quite a few blister beetles,” said Bruce Anderson, forage specialist. “When blister beetles end up in hay and are eaten by horses, they can sicken or even kill the horses. If your alfalfa might be fed to horses, take precautions to protect these animals.”

Although blister beetles appear in Nebraska alfalfa fields every summer, populations usually aren’t high enough to cause problems, Jarvi said. Adult blister beetles rarely are found in first cut or October cut alfalfa, but they can be numerous in late summer, Anderson said. They congregate, or swarm, in small areas of the field and feed on blossoms or leaves if blossoms aren’t available.

“Fortunately blister beetles do not travel far, so they usually are not found beyond the first 50 yards of the field margin,” Anderson said.

There is no sampling method to detect toxic levels of blister beetles in cured hay, he said. Insecticides like Sevin or Warrior can be used, particularly around field margins, but this increases costs and often kills beneficial insects like honeybees. Anderson said one of the best ways to reduce blister beetle problems is to mow alfalfa and swath without mechanically conditioning it. Since blister beetles often swarm, a large group can be crushed and killed by rollers used for mechanically conditioning.

“As a horse eats this hay, it may consume more than 100 beetles from a single flake of hay,” he said. “However, if a conditioner is not used, the beetles will crawl out of the swath and simply fly away.” Blister beetles produce a chemical -– cantharidin -– to which horses are especially susceptible. Cantharidin remains toxic even in dead beetles, Jarvi said. Even a small amount can cause discomfort and colic in horses, he said. Small doses can reduce milk production and weight gains of cattle and sheep. In people, a crushed beetle causes blistering of the skin, hence its name.

In horses, cantharidin can cause inflammation, frequent urination, straining, elevated temperature, depression, increases heart rate and respiration, dehydration, sweating and diarrhea. Since animals can die within 72 hours, it is imperative to contact a veterinarian as soon as blister beetle poisoning is suspected.

Cantharidin concentration varies with the beetle species and sex. In Nebraska, the three striped, gray and black blister beetles are most common, Jarvi said. The striped blister beetle contains five times more cantharidin than the black blister beetle. It takes more than 120 striped blister beetles to kill a 825-pound horse but 1,700 of the less toxic black blister beetles.

Sandi S. Alswager
IANR News Service

If you do use an inoculant, make sure it contains live bacteria – at least 100,000 colony forming units per gram of wet forage when applied at the recommended rate.

Plastic protection. A producer invests time and money to produce high quality silage, but can lose a good part of that investment if the silage isn’t protected. Even after silage has been chopped, piled and packed correctly, it still can be damaged by air and moisture slowly penetrating the outer 3 to 4 feet. In fact, good silage can lose 15-20% of its feed value from fermentation and spoilage under normal conditions. This loss can be cut in half, or even less.

Cover freshly chopped silage with black plastic immediately after you finish filling the trench, bunker, or pile. Then cover the plastic with something to hold it down. Old tires often are used because they do a good job of keeping the plastic from blowing away, but a tire only keeps the plastic in direct contact with the silage directly under it. In between the tires, air can circulate and cause spoilage.

A better choice would be a solid cover, like freshly chopped forage or weeds or a 6-inch layer of manure.

You spend a lot of time and expense to make good silage. Isn’t it worth it to spend just a little bit more to protect that investment?

The clinics offer individual and confidential information and education on farm finances; the laws, regulations and policies governing Farm Services Agency (FSA); debt restructuring and other legal options; and how the mediation program can help work with lenders to find an agreeable and workable solution. The Farm Hotline (1-800-464-0258) must be contacted to make an appointment and to learn the clinic location in the town where individuals wish to make an appointment.

The contact for the Farm Mediation program at the Nebraska Department of Agriculture is Marian Beethe (402-471-6890) or marianjb@agr.state.ne.us

1. get the greatest economic value from a farm’s manure resources,
2. assure compliance with state and federal regulations, and
3. use worksheets and software to simplify planning and record keeping.

The program at each site will cover: Interpreting soil and manure test reports, NDEQ rules and record keeping, developing a manure application plan, manure and soil sampling, applicator calibration, stream setbacks, plus special local topics, as outlined with the meeting announcements below.

• Neligh: Monday, September 20; Antelope County Extension office, County Courthouse Annex, Hwy. 275, Neligh. Contact: Phil Steinkamp CNMP coordinator, at 402-370-4061; special topic: Value of Manure as a Fertilizer Source.

• Ohiowa: Thursday, October 7; At Mid-America Feedlots on the old Bruning Air Base, From Hwy. 82 south of Bruning, 7 miles east on Hwy. 4. Contact: Paul Hay, Gage County Extension, 402-223-1384; special topic: Composting of Solids and Pivot Application of Liquids.

• West Point: Wednesday, October 27; City Auditorium, 237 N. Main St. Contact: Larry Howard, Cuming County Extension, 402-372-6006; special topic: Reducing Phosphorous in Rations, Foliar Toxicity of Effluent.

These workshops are sponsored by Cooperative Extension in the University of Nebraska Institute of Agriculture and Natural Resources and the Nebraska Environmental Trust.

For more information contact Phil Steinkamp, CNMP coordinator, University of Nebraska Lifelong Learning Center, Norfolk, 402-370-4061. (Note: Producers who attended the UNL Comprehensive Nutrient Management Planning (CNMP) winter classes have met the NDEQ requirement.)

“We’ll have representatives from the commercial seed companies on hand to discuss field performance on their plot entries,” said Simonsen, board president and plot coordinator. “Farmers will be able to see and compare hybrid performance for themselves.”

A barbecue beef sandwich meal, featuring sorghum cookies, will be served at 7 p.m.. Rob Heyen of Milford, a sorghum producer and crop insurance consultant, will discuss new lower-cost crop insurance options and how it may benefit a producers’ bottom line.

Dave Morgan, Extension safety specialist, will demonstrate grain entrapment to show the force necessary to remove a victim buried in various levels of grain. He’ll discuss the use of lifelines and safety harnesses when entering bins, grain carts and trucks.

The event also will include a yield guessing contest and door prizes.

Location: From the west edge of Ruskin on Hwy 136 go 4 miles south and 2.5 miles west. From Hardy go 5 miles north and 0.5 mile east. (The site is across the road north of the TV tower.)