More than 25 years ago, Fred Below witnessed 300-bushel corn and that motivated him to research the specific factors that affect crop yield. A professor of Plant Physiology in the Department of Crop Sciences at the University of Illinois, Dr. Below recently launched a new website that makes his findings readily available at www.7WondersOfCorn.com.
Each management practice has been categorized into a “wonder.” The higher up on the list, the more control that factor exerts over the Wonders that follow, Below explains in a recent Hoard’s Dairyman article. When combined, Below says all of these factors contribute to big-yield gains:
On the new 7WondersOfCorn.com website, Dr. Below narrates video segments dedicated to each Wonder. The “News” section provides updates on Below’s real-world plots at the upcoming Farm Progress Show in Decatur, Ill. In addition, there is a 7WondersOfCorn Facebook page where growers can share their own photos and experiences.
Goss’s Wilt, which has plagued Nebraska corn fields since 1969, has been spotted in Iowa this season. Iowa farmers are searching for ways to protect yield potential yet this season, as well as avoid the problem in 2012, says ISU Plant Pathologist Alison Robertson.
There are three products that Robertson says she’s heard Iowa corn growers are trying to treat Goss’s Wilt: Procidic, Kocide and Intercept. Procidic is advertised as a broad spectrum fungicide and bactericide. However, Robertson isn’t aware of any published data for the effect of Procidic against bacterial diseases or use on corn. Kocide is not labeled for use on corn to manage Goss’s Wilt, so Robertson said it should not be used. A third product that Iowa growers are reportedly trying is Intercept. There is very little information available on this product, but it’s reportedly been used in Florida to control citrus canker, which is also caused by a bacterium.
Robertson is monitoring a corn field in Gilbert, Iowa, that had an application of Procidic, as well as an earlier application of Stratego YLD. She says she also will be evaluating fields where Intercept has been applied. At the end of the growing season, ISU researchers will study the effect of both products on Goss’s Wilt disease development and general plant health of the corn.
“Continuous corn production together with minimum tillage practices have in part contributed to the epidemic of Goss’s wilt we are witnessing in 2011,” says Robertson in a recent Wallaces Farmer article. “Other factors include susceptible germplasm and stormy weather.”
To avoid Goss’s Wilt in 2012, farmers should keep recommended management practices in mind. Best practices include growing resistant corn hybrids, using crop rotation and crop residue management.
Some people “paint the town.” At Latham Hi‑Tech Seeds headquarters in Alexander, we’re painting the corn fields!
Research Technician Gary Bennett and I used ½-inch paint brushes to apply nearly 500 earworm larvae to approximately 70 ears each of seven different Latham® hybrids. These hybrids featured various technologies and trait packages, including Agrisure Viptera™ 3111 and Genuity® VT Triple PRO™.
Our research objective is to record the level of corn earworm protection offered by the different hybrid traits and technologies. We’ll be taking field notes to record feeding and crop damage every couple weeks. Watch for photo updates soon!
Farmers across the state are starting to see “tipping back,” where kernels aren’t filling all the way to the end of an ear of corn. In this video report, Latham’s Corn Product Specialist explains why high temperatures for prolonged periods during key corn developmental stages have attributed to the amount of tipping back that’s evident this season.
Stress can result in tipping back, agrees Iowa State University (ISU) Extension Corn Agronomist Roger Elmore. Kernels may not have pollinated in the first place or pollinated kernels may have been aborted around milk stage or blister stage. For more information on what causes tipping back, click here to read a related Wallaces Farmer article. To read how tipping back affected yields in 2010, click here.
Night-time temperatures after silking greatly impact yield. Cool night-time temperatures after silking in 2009 resulted in the highest average statewide corn yield ever recorded in Iowa. On the contrary, warm night-time temperatures contributed to lost yield in 2010.
Symptoms of Goss’ Wilt were reported earlier this growing season in Nebraska and Iowa. With all of the storm damage in these areas, including hail and straight-line winds, it’s no wonder that we’re receiving even more reports now of Goss’ Wilt. Stalk bruising and leaf shredding provide ways for pathogens to enter the corn plant. High night-time temperatures, which we’ve also experienced recently, favor the spread of Goss’ Wilt.
Goss’ Wilt causes large lesions that start on the leave’s margins and eventually encompass the entire leaf. These lesions look very similar to Gray Leaf Spot injury. One simple, but not fool-proof, way to diagnose the difference is that Goss’ will have a waxy appearance due to the different
Note the waxy, shiny appearance to the lesions caused by Goss' Wilt
pathogens that cause the disease. Gray Leaf Spot is caused by a fungus while Goss’ is caused by a bacterium, which means Goss’ Wilt cannot be controlled by a fungicide. Effective control measures include crop rotation, tillage and hybrids that show genetic resistance. Latham’s 2012 lineup has a number of hybrids with excellent disease packages, so keep this in mind as you make your seed decisions in the coming months.
The bacterium responsible for Goss’ Wilt may infect the xylem, or water-conducting tissues of the plant, which results in wilting and death.
Seed selection is most likely going to play an even more important role as Goss’ Wilt becomes more prevalent. Bacterial wilt was first reported in Nebraska more than 40 years ago, and the list of states affected keeps growing. Goss’ Wilt has been identified in Kansas, Colorado, Wyoming, South Dakota and Iowa. The disease has also been confirmed in Illinois and Wisconsin, according to a NebGuide article, “Goss’s Bacterial Wilt and Leaf Blight of Corn,” published by the University of Nebraska—Lincoln Extension.
Sudden Death Syndrome (SDS) typically appears during the last week of July or the first week of August in Latham Country, so farmers are being advised to keep their eyes open for this yield-robbing disease. Cool, wet conditions at planting time can contribute to the severity of SDS.
“Although we do not expect SDS to be as widespread or as severe as the 2010 growing season, there have been some Iowa counties that have received higher-than-normal precipitation,” said ISU Plant Pathologist Alison Robertson in a recent Wallaces Farmer article. “We expect the risk of SDS in these counties to be higher since the development of this disease is favored by wet conditions.”
Scouting for SDS is important for several reasons:
Identifying fields or parts of fields with SDS can help with future management practices. These management tactics include reducing soil compactionsince the disease has been associated with compacted soil; planting fields with a history of SDS towards the end of a planting schedule when soils may be warmer and drier; and testing for the presence of soybean cyst nematodes.
Cyst nematode is usually, but not always, associated with SDS. You may see more severe cases of SDS in soybean varieties that are SCN-susceptible. When selecting soybean seed, it’s best to read through the SDS score rather than judge a bean solely by SCN tolerance.
Planting resistant varieties, or avoiding very susceptible varieties, is the most effective way to reduce losses from SDS. Keeping good field records from year-to-year will help determine which characteristics are most crucial when selecting soybean varieties to plant in a given field in a given year. The following Latham® varieties carry excellent scores for SDS tolerance:
As you prepare to walk your fields, these videos shot last season by Soybean Product Manager Mark Grundmeier will explain what symptoms of SDS to look for in your fields. You might also enjoy watching Mark’s brief, but informative, videos on SDS management and prevention.
Soybean fields are entering the critical reproductive stages and yields hang in the balance. While there are several yield-determining factors that are beyond a farmer’s control, insect pressure can often be managed.
Now is the time to intensify your soybean scouting efforts, advises Iowa State University Extension Entomologist Erin Hodgson. Scout every field right now to see if there is any type of pressure, and keep a watchful eye to see if conditions warrant treatment. We could see outbreaks in late July or early August.
With the predicted market value of soybeans so high, farmers may be tempted to spray aphids at low populations. ISU recommends a threshold of 250 aphids per plant, although some agri-businesses are suggesting that aphids be sprayed when populations are lower. Click here and listen to Hodgson discuss whether research confirms the value of such lower thresholds. In this podcast, she also discusses whether it makes a difference to spray with generic or labeled compounds.
Peter Bixel, Seed-2-Soil powered by Sci Max Team Leader
The effects of this past’s week heat wave on this fall’s corn yields is a main topic of conversation in the countryside. Farmers are wondering if consecutive days of excessive heat will cut yield. It’s true that stress during pollination and silking may result in shorter ears, increased tip back and fewer kernels per ear – all of which contribute to less yield potential. Sometimes.
Fortunately, the availability of pollen is usually not a problem with modern hybrids for a couple of reasons:
At its peak, a plant produces 500,000 pollen grains per day! There is usually more than enough pollen to go around.
Most pollen shed occurs during the morning when temperatures are cooler and moisture stress less evident.
Breeding efforts have significantly improved the stress-tolerance of today’s hybrids. The time between pollination and silking – also known as the anthesis-silk interval (ASI) – is very short with modern hybrids. This shorter ASI results in few barren plants. In older hybrids, however, silking always followed initial pollen shed by at least several days.
The good news iscurrent soil moisture conditions are excellent throughout much of our territory. Likewise, the crop moisture index shows that all of Iowa sits at the midpoint, “Slightly dry/ Favorably moist.” A good share of our soils have high water holding capacity. As the heat spell continues, the differences in mid-afternoon corn leaf rolling between soils with better moisture holding capacities than others will be evident.
High temperature impacts on corn
This heat wave may have a double impact on the crop. The first is the increase in rolling of corn leaves in response to moisture deficiency. By rule-of-thumb, the yield is diminished by 1 percent for every 12 hours of leaf rolling – except during the week of silking when the yield is cut 1 percent per 4 hours of leaf rolling. Unfortunately, most of our crop will be silking next week. The second impact is less obvious initially.
When soil moisture is sufficient, as it is for the most part this July, the crop doesn’t have a measurable yield response to one day of temperatures between 93 F to 98 F. The fourth consecutive day with a maximum temperature of 93 degrees or above, however, results in a 1 percent yield loss in addition to that computed from the leaf rolling. The fifth day there is an additional 2 percent loss; the sixth day an additional 4 percent loss. Data are not sufficient to make generalizations for a heat wave of more than six days, however, firing of leaves becomes likely and very large yield losses are incurred. Generally a six-day heat wave at silking time is sufficient to assure a yield not to exceed trend (Iowa trend yield is near 174 bushels per acre).
Hopefully, this hot-weather trend will end soon! Everything – plants, people and pets – could use a break.
Last week Latham’s Corn Product Specialist Nick Benson posted a video, urging farmers to walk their fields as Corn Borer infestations were spotted in Northeast Iowa. Today he focuses again on European Corn Borer as infestations have risen well over economic thresholds for many producers in the area. His follow-up video further explains why it’s important to catch these pests before they move down the corn stalk.
Click the video link for tips on how to scout beyond the whorl. Make sure you catch your fields before pests move down the plant and “past the point of no return” for foliar-applied control methods.
With foliar-applied insecticides, growers are able to acheive nearly an 80% kill rate. However, when corn borers burrow into the stalk, foliar applications are no longer affective. Growers are then left to rely merely on careful harvest and season management approaches to fight against stalk lodging, ear drop and repeat infestations.
Post-infestation management procedures for harvest and for next season are also included in today’s video by Nick Benson. For more information on scouting for and managing European Corn Borer, contact Latham’s Corn Product Specialist on Twitter @lathamcornguy or contact us directly at this link.
Latham Corn Product Specialist Nick Benson is seeing above-average pressures of corn borer in his northeast Iowa territory. If your acres aren’t protected by a corn borer trait, Nick advises you to check fields as soon as possible for corn borer larvae and consult with an agronomist about treatment if thresholds are met.
Click the video below for information on how to scout your fields for corn borer.
Female moths have dull, buff colored wings while males have brown colored wings.
Corn Borers damage plants when their “boring” tendencies disrupt the plant tissues and interfere with water and nutrient uptake and transfer. Boring into plants creates a wound providing opportunity for infectious disease to enter the plant. Lastly, corn borers can cause weakened stalk and ear strength leading to lodging or ear drop. It’s important to catch these pests early on in the infestation stages to prevent severe damage to the integrity of your plants.
Late-stage larvae commonly tunnel into the earshank of corn.
Management approaches differ according to generation of corn borer, stage of growth in the corn plants and the cost analysis in your field. Iowa State provides these guidelines, but it’s advisable to run an individual analysis and consult with your agronomist for recommendations to suit your unique situation.
For more information on corn borer or management approaches, don’t hesitate to ask questions in the comment box below, or contact us directly.
More than 25 years ago, Fred Below witnessed 300-bushel corn and that motivated him to research the specific factors that affect crop yield. A professor of Plant Physiology in the Department of Crop Sciences at the University of Illinois, Dr. Below recently launched a new website that makes his findings readily available at www.7WondersOfCorn.com.
