When the winter wheat greens up and the Sandhill cranes return to the central Platte Valley, spring can't be far behind. Check the contents for more on both. Photo by Brett Hampton

March 21, 2003

Winter wheat producers will want to be scouting for the army cutworm (bottom) and pale western cutworm (top).

Growers need to be evaluating this situation as winter wheat begins to break dormancy. Eggs are laid throughout the fall, and larvae begin to feed later in the fall or winter when conditions are warm enough. These larvae will develop through the winter and be half grown in the spring when conditions become consistently favorable. The army cutworm is really the only cutworm of significant size likely to be present this early in the spring. The larvae are pale gray with a lighter broad band on the upper surface and a narrower light band along the side. Insects will grow to 1 ½ to 2 inches in length. At any one time a cutworm population would likely include insects of greatly varying sizes.

Wheat (and alfalfa) should be monitored at green-up to determine if army cutworm populations are high enough to cause concern. Larval densities of four or more per square foot may warrant treatment. If the plants are stressed and regrowth is slow, lower cutworm densities (two or more per square foot) may warrant treatment. In determining the need to treat, consider the stress level and vigor of the plants, their ability to regrow, and the yield potential in the absence of insects. Often these insects have a spotty presence in the field with higher populations on the edges or other areas. These infestations may best be handled with spot or border treatments to eliminate problems before they spread further in the field.

Nebraska's winter wheat is greening up and insect problems may not be far behind. Entomologists recommend scouting fields and being alert to the potential for increased insects problems in early spring. Photo by Brett Hampton

A related insect that tends to be much more problematic during consecutive years of dry conditions is the pale western cutworm. Pheromone trapping in the southern Panhandle has indicated that moth populations have been increasing the last few years and are at levels of concern. This insect is much more damaging than the army cutworm as it feeds at the crown and cuts tillers off below the soil line. Because the pale western cutworm overwinters as an egg and hatches early in the spring, its development is delayed compared to the army cutworm. The pale western cutworm is pale gray and does not have distinct striping or markings. It will grow to be about 1 1/4 inches in length.

Normally, serious damage (cutting of tillers) will begin a few weeks after spring regrowth begins and continue into early to mid May. Cutworms tend to be more serious in dry and loose soil areas (e.g. hillsides, hilltops) and can result in serious stand losses in these areas or in very serious cases across the whole field. Wheat growers are urged to be diligent in looking for this insect across western Nebraska this spring. Cutworm densities of one to two per square foot can result in serious reduction in tiller density. Again, plant conditions and density will impact the potential for significant damage.

If economically justified, both species of cutworms are best controlled with pyrethroid insecticides. For more information on management and control of these cutworms, refer to the:

A UNL researcher crosses two wheat cultivars to develop a third with the sought after attribute. Hundreds of crosses will be made and tested in the development of a single new variety. Photo by Brett Hampton

In any breeding program, there are three main phases. The first phase, which usually takes one to two years, is the introduction of genetic variation. This is done by crossing two or more wheat lines. The parental lines can be varieties, but often are experimental lines or even exotic lines that have useful traits. For example, no variety currently released has wheat streak mosaic virus resistance so our crosses for this trait involve experimental lines.

Once the cross is finished, the second phase is inbreeding and selection. Inbreeding is done by selfing (wheat is a naturally self-pollinated plant) so the inbreeding process consists of simply growing the plants and harvesting their seed. We use a breeding method know as bulk breeding in which the progeny are planted and harvested in bulk. The advantage of bulk breeding is that it allows nature to do some of the breeding work. The bulks are initially grown at Mead because it has a harsh winter and will kill winter-tender plants. Also, because it is out of the main wheat-growing region, we can infect plants with stem rust and select for resistant plants. The inbreeding and selection process takes six to seven years. We begin with over three million plants but by the end of this process, we have less than sixty lines. Each of these lines will have winter hardiness, stem rust resistance (thanks to researchers in the NU Department of Plant Pathology), an indication of high agronomic performance, and acceptable bread making quality (thanks to our NU Wheat Quality Laboratory).

The final step takes five years and is known as the evaluation phase. Extensive testing is conducted to provide enough information to decide whether the lines should be released as a variety and, if so, where the new variety would be best grown. Our main breeding nursery locations are Mead, Lincoln, Clay Center, North Platte, Sidney, and Alliance. We formerly also tested at McCook and Grant, but current budget restrictions prevented testing at these sites, although we hope to include them again in the future.

We wanted to test in the major wheat growing regions of the state (east, south central, southwest, and the Panhandle) and at NU farms because we test seed from other states and it is important to make sure we do not bring diseases into Nebraska and and to farmers' fields. Seed from these trials is composited and baked in the Wheat Quality Laboratory. The first trials are in our breeding nurseries. The intermediate trials include regional testing across the Great Plains which is coordinated by the USDA-ARS based in Lincoln. The final trials include the State Variety Trials. The latter trials are very important because they have twice as many locations as our breeding nurseries and are used for field days so producers can see which lines may be released in the future. Before a line is released, it is tested in more than 100 location-years to provide the diverse growing conditions that it may experience at different times and places in Nebraska.

In summary, it takes a minimum of 12 years to create a variety, with over 700 crosses every year. Over three million plants are planted in segregating bulks and 15,000 yield plots are harvested yearly. At the end of his process, if we are very successful, a new vari-ety will be released. As plant breed-ers we know the odds are not in our favor, but the impact a good variety can have is well worth the effort.

Following last year's drought producers who farm dryland or fields with limited irrigation water may be asking themselves whether they should plant grain sorghum or corn To better address this question, University of Nebraska researchers have conducted side-by-side hybrid trials for the last six years in south central and for five years in southeastern Nebraska.

Sorghum has looked very good in these trials, having the highest single yielding hybrid at 177 bushels per acre and outyielding corn four of the last six years in south central Nebraska. The same conclusion can not be drawn from the southeast Nebraska trials, in part due to less data. However, sorghum clearly outperformed corn in 2002 in both southeast and south central Nebraska. Following is a synopsis of the 2002 trials and conclusions drawn from the multi-year trials.

2002 Trials

The 2002 trials were conducted in Harlan and Gage counties. In Harlan County, where it was extremely hot and dry all summer, 20 corn hybrids were planted in the same field with 17 sorghum hybrids. Both crops were planted no-till into wheat stubble that had minimal subsoil moisture. Corn yields ranged from 1 to 39 bushels per acre with an average of 14 bushels per acre. Sorghum yields ranged from 45 to 84 bushels per acre with a 63 bushel per acre average.

In Gage County, which also was hot and dry much of the summer, 60 corn hybrids and 19 sorghum hybrids were no-tilled into bean stubble with very little subsoil moisture. None of the corn hybrids produced grain. Several of the sorghum plots had poor stands. All sorghum hybrids averaged 34 bushels per acre and ranged from 12 to 72 bushels per acre. The top 10 sorghum hybrids averaged 46 bushels per acre with a range of 32 to 72 bushels per acre.

1997-2001 Trials

Multi-year Nebraska trials indicate that sorghum often equals or outyields dryland corn, especially where water resources are limited.

In 1997 the NU dryland sorghum and corn hybrid test plots were planted in the same Nuckolls County field to provide for better comparison. Similar comparisons were made at two other locations from 1998 through 2002. The two crops were compared in the same field, using cultural and management practices appropriate to each. The plots have been in productive soils and the growing conditions have ranged from very poor to excellent. In 1997, 27 commercial sorghum hybrids were compared with 38 commercial corn hybrids in Nuckolls County. Both crops were surface planted after disking. The field had been planted to wheat the previous three years. Average corn yields were 80 bushels per acre with a range of 61 to 107 bushels per acre. This compares to average sorghum yields of 108 bushels per acre with a range of 77 to 124 bushels per acre. The top 10 hybrids of each crop are compared in Table 1 above.

In 1998 similar comparisons were planted in Otoe and Webster counties. In Otoe County, 55 corn hybrids were planted in the same field with 17 sorghum hybrids. Both crops were planted without tillage into soybean stubble. Average corn yield at the Otoe County site was 125 bushels per acre. Individual hybrid yields ranged from 99 to 154 bushels per acre. This compares to an average 133 bushels per acre for sorghum with a 115-158 bushels per acre yield range. Cool and wet conditions during plant emergence and early growth and soil compaction slowed development and emergence of both crops and contributed to poor stands. Corn was yellow after emergence due to excess moisture. In Webster County in 1998, 29 corn hybrids were compared to 17 sorghum hybrids. Both crops were no-till planted into wheat stubble. Average corn yield was 134 bushels per acre with yields ranging from 113 to 172 bushels per acre. This compares to an average yield of 154 bushels per acre for sorghum with a range of 125 to 177 bushels per acre. Conditions were excellent at this site.

In 1999 the trials were conducted in Nuckolls and Gage counties. The Gage County site had over 40 corn hybrids and 21 sorghum hybrids. The plot was planted into soybean stubble and had excellent growing conditions through late summer when it became fairly dry. Most of the corn plot was lost because of a herbicide problem, however comparing the hybrids that were not damaged and the producer's corn in the rest of the field, the corn yielded About 150 bushels per acre. The sorghum averaged 144 bushels per acre with yields ranging from 122 to 170 bushels per acre. The Nuckolls County site was no-till planted into wheat stubble and contained 30 corn hybrids and 18 sorghum hybrids. The growing conditions were fairly wet early and very dry late in the summer. Average corn yields were 88 bushels per acre, ranging from 73 to 110 bushels per acre. The sorghum yields averaged 108 bushels per acre and ranged from 92 to 121.

The 2000 growing season plots were in Nuckolls and Lancaster counties. The Lancaster County field was hailed and the grain sorghum was not harvested. The hail storm was on July 27 before the sorghum had headed. The damage to the top of the plant caused trapping and disease which seemed to prevent the heads from emerging. The corn had already pollinated, and the ears were much more protected than the sorghum. A total of 73 corn hybrids were harvested averaging 76 bushels per acre with a range from 51 to 95 bushels per acre. In Nuckolls County the plot was no- till planted into wheat stubble with 13 sorghum and 23 corn hybrids. The growing conditions were very dry and hot all summer with some rain and cooler conditions in July and a very hot and dry August-September. The sorghum averaged 127 bushels per acre with yields ranging from 113 to 136 bushels per acre and the corn averaged 123 bushels per acre, ranging from 90 to 149 bushels per acre. No-till planting into wheat stubble was the key to these excellent yields. The corn fields on ether side of the plot, which were not in wheat stubble, had yields of less then 20 bushels per acre.

The 2001 trials were in Webster and Lancaster counties. In Webster County, where it was extremely hot and dry during late summer, 18 corn hybrids were planted in the same field with 19 sorghum hybrids. Both crops were planted no-till into wheat stubble. Corn yields ranged from 108 to 160 bushels per acre with an average of 138 bushels per acre. Sorghum yields ranged from 108 to 148 bushels per acre with a 135-bushel per acre average. In Lancaster County, which also was dry much of the summer, 52 corn hybrids and 20 sorghum hybrids were no-tilled into bean stubble. Corn yields averaged 129 bushels per acre and ranged from 104 to 171 bushels per acre. Several of the sorghum plots had a stands below 30,000 plants per acre . They also suffered from added weed pressure form velvet leaf. All plots averaged 95 bushels per acre and ranged from 46 to 137 bushels per acre. However, the top 10 plots averaged 109 bushels per acre with a range of 99 to 137 bushels per acre. The top 14 corn entries in Lancaster County outyielded the highest sorghum entry in 2001 wile only the top 6 sorghum entries yielded better than the worst of the 52 corn entries.

Summary of trial results

When we started this project, we expected that sorghum would outyield corn in dry years, corn would outyield sorghum in wet years, and they would have similar yields in average years. The hybrid trial data show that the corn and sorghum yield comparison was uncertain in the range of 20 to 24 inches of rainfall. Where moisture conditions were less favorable, sorghum was usually the better yielding crop and corn was the better yielder with good rainfall. It also appears hybrid selection is more important with corn than with sorghum because of a wider yield range for corn observed particularly in the south central plots. Data in Table 1, which shows the sorghum and corn yield ranges by year for the south central trials, indicate the yield range for the top 10 hybrids is consistently higher for corn. Table 2 provides data for the southeast Nebraska trials.

Other related results

A study conducted at Mead from 1984 to 2002 compared corn and grain sorghum following soybeans and provided similar results. When May-September precipitation was below 14.5 inches, sorghum outyielded corn over 70% of the time for an average of 5.5 bushels per acre. When precipitation was in the 14.5-20.0 inch range corn outyielded sorghum 70% of the time for an average of 22.8 bushels. Corn outyielded sorghum over 90% of the time when precipitation was over 20 inches in May through September with average corn yields exceeding sorghum by 42 bushels per acre.

Rainfall differences

Whether a producer should expect to have sufficient moisture for corn depends on subsoil moisture and where the farm is located. More than 40 years of weather data is summarized in Table 3. As the table indicates, May through September precipitation has been below 15 inches nearly 70% of the time in McCook. If subsoil moisture were below normal at the start of the season and 5 inches of rainfall could be expected to make up the deficit, one would have to expect 20 inches or more rainfall in the growing season to make up for the subsoil moisture deficit and have the 15 inches or more required to be better off planting corn. McCook has received 20 inches or more only 6.8% of the time (3 in 44 years). The odds look better in Minden and Geneva, but one would have to be as far east as Wymore in Gage County before there would be better than a 50% chance of receiving 20 inches or more.

In on-farm situations, dryland corn may have appeared to yield better because it was usually planted on the best land (most fertile, best subsoil moisture, and most residue cover) while sorghum was planted on the poorer land (eroded hillside with less subsoil moisture and less residue cover). The data reviewed here suggest that when both are planted into the same conditions, sorghum will outyield corn when growing season rainfall is less than 15 inches and corn could be expected to outyield grain sorghum when growing season rainfall is 25 inches. Subsoil moisture levels at the beginning of the growing season also would influence the rainfall needed to favor planting corn. Also the timing of rainfall would influence the amount needed.

Figuring the economics

In addition to yield differences, typically there also are differences in price and production costs. Over the last 10 years, grain sorghum prices in Nebraska have averaged about 25 cents per bushel below the corn price. However, grain sorghum prices actually have exceeded corn prices on several occasions in recent years and the loan rates are the same under the current farm program. (In mid-March grain sorghum prices were quoted in Aurora at a 5 cent premium above corn.) Since production costs are lower for sorghum, by as much as $12 per acre for seed alone, sorghum generally requires less than a 10% yield advantage to net more than corn. For example using 10-year average prices received by Nebraska farmers, 107 bushel grain sorghum at $2.10 per bushel (107 x $2.10 = $224.70) would be more profitable than 100 bushel corn at $2.35 per bushel at a $12 per acre higher production cost (100 x $2.35 -$12 = $223). If yields are below 40 bushels per acre, corn must yield more than sorghum to be the most profitable alternative at $2.35 corn, $2.10 sorghum and an additional $12 per acre cost of growing corn. However, at these yield levels, sorghum typically outyields corn.

Crop insurance

Crop insurance coverage may be an additional consideration in choosing between corn and grain sorghum, particularly when beginning the year with low subsoil moisture. For farms that have a higher proven yield for dryland corn than grain sorghum, it might appear an insured producer would be better off in case of crop failure to have planted corn. However, this conclusion is not necessarily correct, since multiperil premiums are generally higher per dollar coverage for corn. Consider an actual example in Clay County where one could buy 70% coverage on a 100-bushel sorghum yield with a $2.10 per bushel price election or 60% coverage on a 120-bushel corn yield at $2.20 per bushel price election for a premium of $2.24 per acre. The corn coverage would generate an indemnity of .60 x 120 x $2.20 = $158.40 per acre in case of complete crop failure and would realize $143.96 per acre net of premium and an additional $12 per acre growing costs.

The sorghum would generate a maximum indemnity of .70 x 100 x $2.10 = $147 per acre or $144.21 net of premium in case of complete crop failure, slightly more than corn. Further, if you were to raise some sorghum (but corn would have failed completely) and the market price is above the indemnity price, you would gain even more from having planted sorghum even though in our example the yield guarantee on the sorghum, .70 x 100 = 70 bushels, is slightly less than the yield guarantee on the corn, .60 x 120 = 72 bushels and the insurance premium on sorghum is slightly higher. Producers are encouraged to ask their insurance agent for help in making their own comparison.

Conclusion

There are several good reasons to produce dryland corn, including better herbicide selection and better maximum yield potential in excellent years; however, sorghum appears to be a better bet if you are in an area expected to have less than 15 inches of available moisture net of any beginning subsoil deficit. In better moisture conditions planting both corn and sorghum would help diversify the risk. Limitations of the comparisons we have provided include not incorporating beginning subsoil moisture in the analysis of the trials examined and failure to consider the effect of adjusting plant populations (particularly in corn) under drier conditions.

Various colors are used to distinguish soybean seed treatment products.

This decision may be even more important in a year with low moisture as seed applied fungicides will affect overall root health in some instances. In many instances we will see increased plant height, which also reflects increased root growth with seed applied fungicides. This does not always translate into yield advantage, but it could be more important in moisture limited years.

One of the key factors in whether seedling disease problems develop is how much moisture there is at planting. If fields have a history of stand problems and you get that "timely rain" right after the seed is in the ground, history may repeat itself. While general state predictions may be for a drier weather pattern, localized precipitation at planting could cause problems. It would appear to be prudent to go ahead and put the seed applied fungicide on if you have any of the following conditions:

1. History of seedling/emergence problems: if you have a field with a history of stand problems, treat the seed with a good combination product this year.
2. Early planting: if you're considering early planting, fungicide seed treatments are a necessity. Cool, wet soils are very conducive to poor stands without treatment. No-till fields will have cool soils later in the season than tilled fields. These will more commonly have seedling disease problems.
3. Phytophthora history: fields with a history of Phytophthora will need additional metalaxyl or mefenoxam treatment. Even with resistant varieties, treat fields because those with Phytophthora will generally favor Pythium.

Begin by evaluating current alfalfa stands. For maximum production, alfalfa fields should come out of the first winter with 10 to 25 plants per square foot, depending on production potential. Thicken only those areas within the field that need it and skip over those that don't. Drill new seed as early as possible in the spring. Any delay can be detrimental to the new plants by increasing the risk of weeds and competition.

Drill new seed only about a 1/4 inch deep, using a drill that can cut into untilled soil. A grain drill with a box for small seeds will usually work, but sometimes a more rugged no-till drill is needed. Use five or six pounds of seed per acre for fields with at least half a stand. For fields with less than a quarter of a stand, use a full seeding rate.

Take the first cut extra early to help open the canopy so new seedlings can get more sunlight. To kill moisture-robbing weeds, use Poast, Select, Buctril, Pursuit, Raptor and Butyrac. They can selectively control grassy or broadleaf weeds with out harming new alfalfa.

Several herbicides can help control winter annual grasses and weeds in alfalfa. They include Karmex, Sencor, Velpar, Sinbar, Pursuit, and Raptor. They all control mustard and pennycress. Karmex and Pursuit do not control downy brome very well, but Karmex has enough residual soil activity that can help control a few summer annual grasses like foxtail and barnyardgrass. To be successful, though, you must apply most of these herbicides soon -- before alfalfa shoots green-up this spring -- to avoid injuring alfalfa. If alfalfa shoots are green when you spray, growth may be set back two or three weeks.

The 2002 Farm Bill authorized the use of certified technical service providers (TSPs) from private industry to help meet a growing demand that is expected to exceed current staffing capacity of NRCS and conservation districts. Individuals from the private sector, non-profit organizations, and public agencies can be certified for planning, design, layout, installation, and checkout of approved conservation practices. NRCS and conservation districts have traditionally provided these technical services, and will continue to do so; however, funds will now be available to reimburse producers who choose to use certified TSPs.

Individuals wanting to be TSPs may work through professional organizations - such as the American Society of Agronomy and the Society for Range Management - or they can prove privately that they meet the required qualifications. can prove their experience and education andthrough other routes. (The process is relatively streamlined for certified crop advisors in the ASA program with credits in the appropriate categories for which they're seeking TSP certification.)

An NRCS Web site (see box) provides further information on the steps to becoming a TSP, the 35 technical service categories and criteria options for certification in each category. One of the first steps in the process is applying for an on-line electronic government account at your local USDA Service Center. This will provide access to resources and forms, many of which can be filed on-line. An American Society of Agronomy Web site (see box) also provides information on how CCAs can be certified as TSPs.

For information on CCA programs in Nebraska, contact Dee Peterson, Nebraska CCA coordinator, at the Nebraska Agri-Business Association at 476-1528.

Management tip

• The six-month notice policy that applies to annual cropland leases does not apply to pasture leases in Nebraska. A 1955 Nebraska Supreme Court decision stated that pasture leases may be terminated without giving six months notice if the pasture lease is for less than 12 months. The pasture lease period in Nebraska generally is from May through October. Tenants should contact their landlords to make sure their pasture lease is going to be renewed.

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