August 17, 2001
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Insects Wheat Diseases Resources Alfalfa Other AgNews
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Rains, some heavy and some slow and steady, provided relief to the state's field crops this week, following weeks of above normal temperatures. Unfortunately the relief may have come too late for fields which became vulnerable to disease infection during the periods of high heat, high humidity, and high plant stress.
While individual pest outbreaks may not be enough to limit yields, often the plant becomes weakened and vulnerable to other challenges. Eventually, depending on the overall damage, harvest may be more difficult and yields may be affected. Jim Stack, Extension plant pathologist at the South Central REC, has identified fusarium wilt in soybean fields in a widespread area of south central Nebraska, often in irrigated fields.
"When you look at the field it looks like moisture stress, but when you examine individual plants, their vascular systems are plugged. While there is no treatment at this point, it is important to have the problem correctly identified. If soybeans are to be planted to the same field next year, it will be important to select a variety resistant to fusarium wilt."
The fungus which causes this disease will remain in the field and spread to new soybeans next year.
Stack said he also had received several calls by midweek about what may be another disease developing in corn in south central Nebraska. Samples are expected to provide further information.
Check the Stack's Plant Disease Central Web site for further updates on these developing diseases.
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Two generations of bean leaf beetles develop in Nebraska. The second generation over winters as adults and are the beetles seen early in the year feeding on seedling soybeans. These beetles feed, mate, lay eggs and die in early-mid June. There is usually a distinct period from mid June to early July when few if any beetles are present in the field, before the first generation emerges.
Total developmental time from egg to adult can range from 25 to 40 days. Because of this range of development, it is common to see adults from the first generation and the second generation in the field at the same time. Because the generations can overlap beetles can be present at some level from mid-July until the end of the growing season. Because of this overlap it is important to monitor beetles regularly to determine shifts in population, which will aid in management decisions.
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Bean leaf beetles will feed on soybean leaves throughout the season, but leaf feeding seldom causes yield loss. Most damage (economic yield loss) occurs when beetles feed on the developing pods. This yield loss can occur in several ways. Pods may be clipped from the plants, however this is not the primary cause of yield loss. Many flowers and pods are aborted naturally and to blame pod loss on bean leaf beetle feeding may be a costly mistake.
There are no thresholds that consider pod-drop. Beetles normally injure soybean pods by feeding on the outside layer of the pod, leaving a thin layer of tissue covering the seed. They do not usually eat into the developing seed, although this may occur on very small pods. Fungal pathogens may enter the pod from the feeding sites, causing seeds to appear shrunken, discolored, and moldy, which can result in dockage. After full pods are formed and seeds begin developing, soybeans are most susceptible to yield loss from pod feeding.
The best time to sample is before significant pod feeding occurs, but after second generation beetles have emerged. Second generation bean leaf beetles are emerging now and beetles numbers will be approaching their highest levels for the summer. Beetle numbers will slowly decline as beans continue to mature and move to over wintering sites. Economic thresholds have been developed for two sampling methods: drop cloth (beetles per foot of row) or sweep net (beetles per sweep).
Sampling methods
Perhaps the most accurate way to sample beetles is with a drop (or shake) cloth. A drop cloth is a 3 x 3 ft piece of muslin or plastic attached on each side to dowel rods. Hold one rod against the base of the plants and lay the cloth between the rows. Shake the plants against the cloth to knock off the insects, and count the beetles. Remember to estimate the number per row foot, so if you use a three-foot cloth divide your total by three. Also, sample through the field in several areas to get a good estimate of the population. In narrow row beans you can still sample with a drop cloth, but the procedure is slightly different. Set the rod at the base of the row of plants you want to sample and lay part of the cloth on the ground and hold the rest of the cloth upright or over the opposite row to be sampled. Shake the soybeans against the upright cloth, and then count the beetles knocked down on the bottom of the cloth.
If the beetle counts are below the economic threshold, scout the field again about five days later. Stop scouting when the beetle counts begin to decline, the soybean pods begin to yellow (R7), or the field is sprayed. Thresholds are based on the number of beetles per foot of row, which varies according to total management cost and the crop value per bushel.
The tables show economic thresholds for beans in 30-inch and 7-inch rows. To use the tables find the number that fits both crop value and application costs. For example, if you set the value of your soybeans at $6.00 per bushel and your application costs at $9.00, you would need 6.8 or more beetles per foot of row to justify an application in 30-inch row beans, or 1.6 or more beetles per foot of row in 7-inch row beans.
Sweep at least five randomly selected sites. Walk through the field at an even pace, performing about 25 sweeping arcs. The best sweeping action for bean leaf beetle is a consistent upward motion through the foliage, using as much force as needed to move the net smoothly through the foliage. Bean leaf beetle activity varies during the day. Activity patterns suggest the best times to sample are around mid-morning or in the afternoon. Try to maintain a similar sampling time in each field to eliminate variability.
Economic thresholds for reproductive stage soybeans other than R6 are probably higher (more beetles are needed to justify a treatment). This is because pods on plants past R6 are maturing and there is less green pod tissue available for beetle feeding, and plants in earlier reproductive stages have greater yield compensation potential than those in R6 or older. Several insecticides can be used to control bean leaf beetles. Be aware that most have pre-harvest intervals of 14 or more days. Information on insecticide selection and use can be found at the Entomology web site.
Tom Hunt
Extension Entomology Specialist
Haskell Ag Lab, Northeast REC
Keith Jarvi
Integrated Pest
Management Assistant
Northeast REC
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Tom Hunt is an assistant professor of entomology and Extension entomology specialist based at UNL's Haskell Agricultural Laboratory near Concord. The lab is part of the Northeast Research and Extension Center. He received his B.S. in horticulture, M.S in entomology, and Ph.D. in entomology at UNL. He worked as UNL sorghum entomology technologist in southeast Nebraska in the mid 90s and joined the faculty at Concord in 1999.
Hunt's research and extension projects focus on corn and soybeans, but also include some alfalfa and potato projects. His work falls in the general categories of economic threshold development, resistance management, insect pest biology and behavior, emerging problems, and product efficacy. Collaborators or cooperators are included on most of the projects and include farmers, industry, commodity groups, and researchers and extension personnel from UNL, other universities, and the USDA. Some of his current projects are:
Corn related research
Soybean related research
Alfalfa related research
Potato related research
Hunt participates in a variety of extension programs including Crop Protection Clinics, Crop Management and Diagnostic Clinics, and various other workshops. He contributes to the Crop Watch and NEREC IPM and Crop Production newsletters, and has authored/co-authored various NebGuides and NebFacts. He is a member and collaborator on several regional research committees related to pest management in corn, soybean and alfalfa.
"We have a solid entomology team at HAL/NEREC," Tom said. "I work closely with Keith Jarvi, the IPM assistant stationed at Norfolk, and I have an experienced technologist, Jerry Echtenkamp. Our goals are to develop and provide comprehensive insect management recommendations, be responsive to the current needs of our clientele, and anticipate new needs and problems that will be experienced by Nebraska farmers."
Hunt can be reached at the Haskell Agricultural Laboratory, NEREC, 57905 866 Road, Concord, NE 68728; by phone: (402) 584-2863 or via email.
| Compare varieties University of Nebraska wheat variety trial results are available on the Web or in a booklet available from your local Cooperative Extension Office. (The latest version is due out in early September.) |
As producers review this year and look forward to planting next year's wheat crop, consider how implementing some of the following Best Management Practices can affect your operation and potential yields and income in 2002.
Seedbed preparation
This is of utmost importance. Try to do everything possible to have a firm moist seed bed at planting. Disc drills used in a loose seed bed almost always guarantee root and ground rot problems. Hoe drills are better able to reach firm moist soil. Hoe drills with wider row spacing are preferred under dry conditions because they can build a bigger furrow and plant deeper. Remember that with wider row spacings you'll give up crop competitiveness and have more weed problems.
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Planting date
Try to plant your wheat as close to the suggested planting date for your area as possible (see Figure 1). Earlier seedings are more subject to root and crown rot and many other diseases and insects, for example wheat streak mosaic and Hessian fly. If you seed more than a week or 10 days after the recommended seeding date, it is important to use row-applied starter fertilizer. This is important even if your soil tests high in phosphorus. Also with later plantings, since less tillering occurs it is usually desirable to increase seeding rates. Seeding rates should be increased to about 1.4 million seeds dryland and 2.0 million seeds irrigated because of reduced tillering. With late seeding also adjust row widths -- narrow rows of 7 2 inches for dryland and 6 inches or less for irrigated are preferred.
Dry soil
When the soil's dry, should producers seed or wait? Most recommend that once you get close to or just past the suggested seeding date (e.g. when seeding after another crop), the crop should be seeded as soon as possible. There are several reasons for this:
As with all situations there are exceptions to the rule. If your seed bed is very loose and you cannot do a good job of placing the seed in the soil, your best option is to wait until after a rain to get firmer soil. Good judgment can help guide your assessment of your field.
Variety selection
Selecting a variety is one of your most important decisions and, if not well made, can negate all the other right decisions you make. Generally, seeding several varieties with different attributes is beneficial. No wheat variety is perfect and seeding several spreads the risk.
When selecting varieties make sure they have different pedigrees and are not too closely related. Also consider the variety's yield and resistance history in field conditions similar to yours. The University of Nebraska Variety Evaluation Program is a good source of information on how various varieties fared under recent conditions. Contact your local Cooperative Extension Office for variety results.
In 2000-2001 there were two tests -- one in Furnas County and one in Perkins County -- where winter wheat was seeded no-till after field corn. This was the second year for this test, which found that many of the wheat varieties responded differently to these conditions. Producers who are seeding in these conditions may want to look closely at this information before selecting varieties to plant next year.
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The two nutrients that winter wheat responds to on most fields are nitrogen and phosphorus. Anhydrous ammonia continues to be the least expensive form of nitrogen. The only way to get a good idea of your soil's need for nitrogen is to take soil samples down to at least three feet and test for residual nitrate. A topsoil sample 6 to 8 inches deep will provide information on the phosphorous level.
There are many different application methods to apply fertilizer. Whichever method you choose, be careful not to loosen the seed bed. Avoid applying anhydrous ammonia with shanks after mid-June because it's difficult to firm a seed bed in dry years. Anhydrous ammonia can be applied until shortly before planting when using an applicator like a rod weeder.
For each bushel of wheat to be produced, 2 pounds of nitrogen is needed. This nitrogen can be provided by residual nitrate in the soil profile (which can be determined by soil sampling and analysis), the soil organic matter, manure and organic material, legumes, irrigation water, and fertilizer.
Weed management
If downy brome has been a problem in wheat, rotation may be the best solution. Another option may be the use of Maverick, a new herbicide introduced in 1999 for downy brome control. It should be applied shortly after the downy brome emerges and before it tillers in the fall. It has been very effective especially if a rain occurs after application. Producers should check their fields shortly after wheat emergence to determine whether downy brome is a problem to provide for timely herbicide use, if necessary. Pre emergence and latepost emergence applications have not been nearly as effective as earl post eemergenceapplications.
Winter annual broadleafs. Also in the fall check your fields for winter annual broadleaf weeds like field pennycress. Timely spraying is necessary to save moisture and nutrients for the winter wheat crop. For more information check the UNL publication, 2001 Guide For Weed Management In Nebraska, EC01-130, which is also available from Cooperative Extension offices.
For more information on wheat production see the revised Wheat Production Systems Web site and click on the link to the Handbook.
Robert Klein
Extension Cropping Systems Specialist
West Central REC
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The Wheat Production Systems web site brings all of the University of Nebraska's Extension information on wheat to you with just a click of your mouse. NebGuides, Extension Circulars, and other materials are available on wheat-related topics such as plant development, freeze injury, variety selection, fertility, planting, stand evaluation, weed, insect, and disease control, irrigation, harvesting, equipment rental rates, current and historical cash prices, marketing, livestock feeding, and fallow management. The site is updated several times a year, with new links frequently being added. It has never been easier to access the latest wheat production information from UNL Cooperative Extension.
For the latest fertilizer recommendations for wheat production in Nebraska, check the 176-page NU Extension Circular EC155, Nutrient Management for Agronomic Crops in Nebraska.
The manual contains two components - a section outlines nutrient management principles and key information on macro and micro nutrients and a section containing fertilizer needs, strategies and recommendations for specific crops. The manual costs $25 and is available from your local Cooperative Extension office. Further information about the publication and sample chapters are available on the web at http://cropwatch.unl.edu/nitrogenissue/ec155.htm or from your local extension educator.
The following is excerpted from the USDA Wheat Situation and Outlook Yearbook for 2000-2001, which is available on the Web at the Economic Research Service site. The article, The Effects of the Federal Crop Insurance Program on Wheat Acreage, is by Monte Vandeveer and C. Edwin Young, both ERS Ag economists.
"The Federal crop insurance program insured more than 45 million wheat acres in 2000/01, roughly 73% of planted acres. Catastrophic (CAT) coverage is declining in importance, while revenue insurance has become prominent in just a few years. The changes in premium subsidy rates established by the Agricultural Risk Protection Act of 2000 (ARPA) are likely to reinforce the trend toward using higher insurance coverage levels and revenue insurance. Wheat ranks third, behind corn and soybeans, in terms of acreage insured and premiums collected.
"Among wheat producers, yield insurance products accounted for most of the insured acres in previous years, but revenue insurance products appear set to take the lead for the 2001/02 crop.
"Analysis indicated that wheat acreage under the ARPA premium subsidy structure is about 0.5% higher than total acreage in the absence of any insurance program. While subsidies tend to increase acreage, the resulting higher production dampens wheat prices slightly and limits the acreage shift."
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The pests were mainly early instars mixed with some later instars. Several generations of garden webworms develop each season, the last of which may overwinter in the soil in the pupal stage. Larvae feed on a wide variety of low plants, including alfalfa, clover, beans, soybeans, sugarbeet, maize and cotton.
Garden webworms, which are not common pests in Nebraska field crops, are pale green or yellow-green caterpillars with rows of strong, somewhat elongate, black spots on the upper half of the body, and rows of lighter (gray) spots on the lower half of the body (below the spiracles). The head is whitish-tan with brown speckles and has a distinctive black spot on each side near the thorax.
Garden webworms have been especially problematic in areas of Kansas this year. Kansas State University entomologists reported they were webbing the foliage of alfalfa, some weeds – particularly pigweeds – and less frequently, soybeans. Leaf surfaces take on a brown, netted appearance as green matter is stripped, leaving only the network of leaf veins to dry and curl inside the webbing.
This is a multiple generation pest which may persist until late in the year. Alfalfa producers may face particular problems with webworms in newly planted seedling fields. Growers are urged to pay close attention to the new growth for signs of webworms, especially if they've been a problem in the area. That new growth should help recharge some of the stored carbohydrate reserves that the crown and taproot depend on.
The best control method in alfalfa is to harvest the crop, if possible. KSU entomologists suggest that treatment may be needed in alfalfa if significant defoliation involves 25% to 30% of terminals. A variety of foliar insecticides should provide good control of webworms. See the Entomology web site for a list of insecticides labeled for use in alfalfa.
Bob Wright
Extension Entomologist
South Central REC
Keith Jarvi
Extension IPM Assistant
Northeast REC
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Waging a low-flying battleA crop duster sprays a field in Custer County in central Nebraska last week. With the variety and number of insect outbreaks this summer, demand has been high for aerial applicators. The Nebraska Department of Agriculture has licensed 303 aerial applicators, 74 of whom are from outside Nebraska, according to Buzz Vance, NDA certification specialist. The profession of crop dusting often requires a pilot to be fairly mobile and migrate to where the work is, following the maturing crops from Texas north as the season progresses. (IANR Photos by Brett Hampton) |
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To correctly identify charcoal rot in soybeans, it is critical that plants be examined within a small window of time immediately after plant death. With the current dry conditions in many parts of the state, charcoal rot may be developing in soybean fields. Charcoal rot is a fungal disease favored by hot, dry weather at this stage in crop development. This is why the disease is also known as "dry-weather wilt". Early symptoms are a wilting or flagging of soybean leaves during the midday heat with plants recovering in the evening.
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With wet conditions in much of the state earlier in the season, wet spots in fields may now appear to have Charcoal rot symptoms. In some cases, the distribution can help differentiate these problems. Charcoal rot symptoms usually begin in the driest areas of the field. Look in sandy or compacted areas, terrace tops, or along tree lines where moisture is generally less abundant. Charcoal rot also can appear in lower, wetter field areas, but in these instances, plants usually have symptoms of root rot from a previous infection of Pythium, Phytophthora or Rhizoctonia.
The root system damage, which resulted from early season seedling disease fungi, places added stress on the plant, putting it under moisture stress. In these situations the charcoal rot fungus is a secondary invader that finishes killing the plant, in some cases. In other cases the wilt and death can be due to early season root injury which has compromised the plant so that it cannot gather enough moisture to survive the hot, dry conditions.
Cultural practices that conserve soil moisture are the main management tool for charcoal rot. As the fungus forms microsclerotia, tillage will have no effect on disease levels with this pathogen. Conservation tillage methods, which conserve moisture, will benefit production in fields with this problem. Other cultural practices which can reduce losses to charcoal rot include earlier planting to provide canopy cover of soil and avoiding high plant populations.
Loren J. Giesler
Extension Plant Pathologist
Hot, windy days cause alfalfa fields to dry up quickly. Irrigation helps, but it can stimulate weeds and actually weaken alfalfa stands if not done properly.
Alfalfa uses a lot of water - up to 40 inches a year and sometimes over .33 inch a day. To keep up with this need, sometimes producers irrigate from the moment hay is removed from the field until the next cutting starts. Constant watering, however, has costs besides fuel and depreciation.
Constant watering encourages grassy weeds like foxtail and perennial grasses like bluegrass to invade alfalfa. Constant watering also weakens alfalfa plants by encouraging root diseases and by reducing oxygen content of the soil. Irrigation management in alfalfa should encourage deep rooting of alfalfa and dry surface soils during harvest.
Stop irrigating a couple days before harvest to allow the surface to dry out and become firm. Heavy wheel traffic on soft, moist ground can severely damage alfalfa crowns. After harvest, don't irrigate until alfalfa regrowth is three to four inches tall. That way, shallow rooted weeds like foxtail and bluegrass will be unable to grow until the alfalfa has a head start. To be sure the alfalfa regrows rapidly, irrigate so that deep water will be available to alfalfa roots rather than the shallower weeds. By putting on a little more water a little less frequently, your alfalfa can be cleaner, healthier, and more productive.
Bruce Anderson
Extension Forage Specialist
If you have manure to spread during summer, sometimes the only place available is an alfalfa field, however this can cause problems for the alfalfa.
Liquid manure can burn leaves due to salt injury, and dry manure can smother plants if it is applied too heavily or in large chunks. Manure can spread weed seeds, and the nitrogen in manure can stimulate grasses already in the alfalfa to become more competitive. Also, manure application equipment can damage alfalfa crowns and compact soil. If you have other fields where the manure could be applied, do. If it is you only option, follow these suggestions:
Bruce Anderson
Extension Forage Specialist
Heat and drought have caused dryland corn to mature or dry up very rapidly the past couple weeks. Many fields are now ready to chop.
As I noted in the story two weeks ago, moisture content at chopping is the most critical factor influencing corn silage fermentation. Wet silage will run or seep, carrying away valuable nutrients. Often it will have a sour, smelly, unpalatable fermentation. Dry silage is difficult to pack and allows more oxygen to remain embedded in the silage. Often this will heat and mold, lowering energy value and protein digestibility.
Adding water to dry silage is impractical. It takes about seven gallons of water for each ton of silage to raise moisture content just one point. It would take 700 gallons of water to increase 10 tons of chopped corn from 55% moisture to a more desirable 65% moisture level. A more practical solution is to blend a wetter feed, like fresh alfalfa, forage sorghum, or green soybeans with dry corn. If you get the right combination it can produce excellent silage.
Most importantly, you need to minimize oxygen in your silage. As silage gets dry, adjust knives to cut finer. This makes it easier to pack tightly. Be sure to do some extra packing even if it seems to spring right back up at you. Putting a foot or two of really wet silage on top also will help. The extra weight aids packing and the wetter silage seals out air better. Always cover dry silage with plastic.
To get the best silage: harvest at the right moisture level, chop fine, pack well, and cover with plastic.
Bruce Anderson
Extension Forage Specialist
The Women in Agriculture: The Critical Difference Conference will bring together women from across Nebraska and surrounding states to learn about their agricultural profession. The Sept. 13-14 conference will be held in Kearney and is sponsored by University of Nebraska Cooperative Extension It offers a "broad, broad spectrum of farm/ranch management education," said Deb Rood, NU agricultural economics programs coordinator.
Keynote speakers include Ruth Patterson, project officer for Tasmania (Australia) Women in Agriculture; motivational speaker Jolene Brown of West Branch, Iowa; cowboy poet R.P. Smith of Broken Bow, Neb.; and humorist Lynette Brown of Oxford, Neb.
The conference offers 17 workshops, designed to fit different types of agriculture. Topics include major tax law revisions, income tax management, using new technologies such as handheld computers and cellular telephones, identity theft, labor issues, contract farming, water law, estate and retirement planning, rental contracts, computerized financial record-keeping, basic and advanced marketing, Initiative 300, value-adding products, livestock diseases, and marriage and family communications.
Presenters include specialists in NU's Institute of Agriculture and Natural Resources, consultants, farm and ranch women, and individuals from the private sector and industry.
One of the conference's biggest assets, Rood said, is in providing a support network for participants and recognizing the critical role they play in Nebraska agriculture. "Women need to understand the value they bring to the operation. Many times the family recognizes the role but does not always express their appreciation for the many things women do to make the business and family work," Rood said. "If you don't love the way of life, the business will fail," Rood said, "but you can't stay (in the business) just because you love the way of life -- it has to make a profit, too. They're so intertwined you can't pull them apart."
Women, Rood added, "are the critical difference in many families" because they play a major role in providing a foundation for both the way of life and the business. The cost for registration, meals and materials for the two-day conference is $65 before Sept. 7 and $75 after. To register or for more information, contact Rood at (800)535-3456 or check http://wia.unl.edu on the Web. Lodging reservations may be made by calling the Kearney Holiday Inn at (800)248-4460.
IANR News Release
Livestock producers need to update or get a new Nebraska Department of Environmental Quality livestock permit after changes in the law went into effect in 2000. Doug Jose, University of Nebraska agricultural economist and host of the broadcast discussion, "Market Journal", will discuss the change with guests Rick Koelsch, NU livestock bio environmental engineer, and Larry Howard, NU extension educator in Cuming County.
Before legislative changes in 1998 and 1999, the law focused on engineering issues, however the new law emphasizes livestock management issues. All Nebraska livestock producers must update their permit to be in compliance with the new laws or have the NDEQ check their operations to see if a permit is required.
"It's a multiple step process," said Koelsch, an NU manure management specialist. "Producers are required to maintain records of the utilization of manure and how they managed facilities over a period of five years."
The Aug. 23 edition of "Market Journal" will be webcast from 8 to 9 p.m. CDT at marketjournal.unl.edu. It also will be aired on Nebraska satellite channel 107 Friday, Aug. 24 from 9 to 10 a.m. CDT.
"Market Journal" is produced by NU Cooperative Extension and the Department
of Agricultural Economics on the second and fourth Thursdays of each month. For
more information, visit the Market Journal web site.
Paul Hay , Extension educator in Gage County: A Sunday afternoon storm damaged a mile wide swath across the county with mild to severe hail. We have had a significant hatch of wooly bear caterpillars in the past week, but they have largely been killed soon after emergence by a fungus disease. Devoured by hyphae, what a way to go!
Gary Hall , Extension educator in Phelps and Gosper counties: A major hail storm tore through central and southern Gosper County, destroying corn and soybean fields. Producers will probably harvest the crops for feed in that area. Recent rains will make irrigators consider when to schedule their last irrigation, if they haven't already done so.
Bob Wright , Extension entomologist at the South Central REC, Clay Center: Numbers of yellow wooly bear moths have increased greatly in our light trap since last weekend, with 244 found Aug. 13, and 247 over the weekend. I have received similar reports from other light traps in the area. We have the potential for large numbers of wooly bear caterpillars as we saw last year. On the bright side, the fungus disease which killed many caterpillars in soybeans the last few weeks also attacks wooly bears, and may help reduce numbers. UNL light trap data is available on the web. We also are seeing high numbers of green cloverworm moths in our light trap. These dark moths often are found gathering around homes, especially in rural areas, and may be a nuisance if abundant. Monitor fields for possible development of caterpillars. On soybeans treatment would be recommended if defoliation reaches 20% and caterpillars are actively feeding.
Jim Stack , Extension plant pathologist at the South Central REC, Clay Center: Downy mildew has been identified in at least two pivots of a forage soybean (maturity group 6). Based on distribution of symptoms on the plant, infections probably occurred in mid July during a period of relatively cool (75 - 85F) weather. The pivots provided the necessary moisture and humidity required for this disease to develop. The gray brown growth of the fungus often can be seen on the underside of the leaf lesion. The fungus can be identified microscopically by the production of its reproductive structures: the sporangiophores and sporangia.
Jennifer Chaky
, coordinator of the UNL Pest and Plant Diagnostic Clinic: The following diseases were diagnosed July 30 - Aug 10:
Corn -- Bacterial leaf blight (Holt County), Bacterial stripe and leaf spot (Holt County), Northern corn leaf spot (Cuming, Dodge and Holt counties), Northern corn leaf blight (Holt County);
Soybean - Fusarium (Butler, Cedar, Holt, Lancaster, Madison, Pierce, Platte, and Saunders counties), Phytophthora (Cedar and Kearney counties), Pythium (Holt, Kearney, Pierce and Saunders counties), Rhizoctonia (Butler, Lancaster, and Pierce counties).
Nebraska Agricultural Statistics Service: As of Sunday, corn condition rated 4% very poor, 9% poor, 26% fair, 43% good, and 18% excellent. Irrigated corn was 75% good to excellent while dryland corn declined to 41% good to excellent. Sixty-nine percent of the fields had reached the dough stage, compared with 72% last year. Twenty percent had dented, which compared to 27% last year.
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