Newsletter- June 2022
Corn Fungicide Application After Damaging Storms
The last two weeks we have seen some intense weather events, from 2” hail, to straight line winds flattening fields across the heart of Central Illinois. I encourage growers to not take your foot off the gas with this crop. We have potentially the highest valued crop in history, and you deserve to get every bushel. It has been a couple of days since high winds and buckets of rain came through, and most of the corn is standing back up. Some will be goosenecked this fall and others will hardly be noticeable.
With the severity of the winds, we experienced there will be a lot of corn leaves that got tattered or torn. Those openings in the leaves will give diseases a perfect entry point into the plant to wait for the right time to start causing damage and robbing yield. Many diseases are soil born and live on plant residue. When we get heavy rains like we have experienced this spring, dirt splashes up on the plant and exposes the plant to the pathogen. According to the disease triangle, you need you need 3 things. A host, a pathogen, and the right environment.
When these three things come together, you have the formation of a disease, and there is good chance we will see heavier than normal disease pressure just from the amount of damage that has taken place so far, this growing season.
I feel this year we need to make sure we are planning at least one fungicide pass with a preventative and curative mode of action. Ideally, I am recommending two passes of fungicide, one with a preventative and a second trip with both modes of action. Many stalk diseases start early by water splashing dirt which is carrying the pathogen into the whorl of the plant or splashing up on the leaf and water carrying it down the leaf and entering at the leaf sheath. Stalk diseases typically do not show their presence until grain fill. At that point it is too late to treat. ProHarvest Seeds has put together a great article about corn diseases including management tips.
Disease Triangle
Corn Leaf Diseases
Leaf diseases may exhibit similar symptoms or have multiple diseases present at once, and laboratory culturing or microscope examination may be required for diagnosis.
Stewart’s Bacterial Wilt
Symptoms of Stewart’s wilt or Stewart's disease are long, green-gray, water-soaked lesions that roughly follow leaf veins with wavy margins. Systematically-infected plants may be stunted and showing signs of wilt, which can lead to plant death during the seedling stage. Cavities may form in the stalk near the soil line. The leaf blight phase is more common and appears after tasseling. Leaves are streaked with gray-green to yellowgreen lesions (Figure 1), noted by the presence of a flea beetle feeding scar toward the base of the streak. Streaks are long and irregular, turning tan as the tissue dies. Flea beetles are the primary vector, and incidence of the disease is relative to the size of the beetle population.4
Goss’s Wilt
Seedlings can be systemically infected, which may cause wilting and death. Vascular bundles may be discolored. More common later-season infections of leaves produce dull gray-green to necrotic lesions often with irregular margins (Figure 2). Small, water-soaked “freckles” appear within developing lesions. Bacterial droplets may ooze from infected tissues early in the morning leaving a shellac-like appearance when dried on leaf surfaces. Plant injury, such as hail or wind damage, can increase infection.5
Anthracnose Leaf Blight
Oval to irregular-shaped water-soaked lesions on the youngest leaves turn tan to brown often with yellow to reddish brown borders (Figure 3). Small, black hair-like structures may sometimes be visible in the middle of lesions.1 Heavily infected leaves can wither and die. This disease thrives in warm, humid weather. The same fungal pathogen is responsible for both anthracnose leaf blight, top die back, and stalk rot; however, the presence of leaf blight does not indicate that stalk rot will be a problem later in the season. The stalk rot phase is often more damaging than the leaf blight phase.2
Eyespot
Small (less than 1/4 inch), circular, translucent lesions surrounded by yellow to purple margins that visually produce a halo effect. Lesions occur early or late in the season, on leaf sheaths and husks. The disease is favored by cool, moist weather.3
Physoderma Brown Spot and Node Breakage
Small yellow spots appear first at the base of the leaf and over time turn brown in color. As infection progresses, spots can often be found occurring in bands across the leaf. Spots in the mid-rib of the leaf become reddish to brown in color and combine to form irregular blotches. Infected stalks may break at a node (Figure 5).6 This fungus is favored by warm, wet weather.
Northern Corn Leaf Blight
Long (up to 6 inches), elliptical to cigar-shaped, graygreen lesions that eventually become tan-brown are symptomatic of infection by this fungus. Infection begins first on lower leaves and as the season progresses the disease can be found in the upper canopy of the plant. Lesions may form in bands across leaves as a result of an infection in the whorl. The disease is favored by high humidity and moderate temperatures. Under humid conditions, lesions may appear dark, and fuzzy because the fungus is sporulating on dead tissues (Figure 6).6
Southern Corn Leaf Blight
Small, elongated (0.25 to 0.75-inch long), parallel-sided lesions that are tan with brownish borders are typical, although symptoms vary considerably on different corn products, often requiring microscopic examination of the fungal structures to confirm diagnoses. Blight primarily attacks leaves, and will overwinter in corn residue. This disease favors high humidity and warm temperatures.6
Common Rust
Small, cinnamon-brown, powdery, circular-to-elongated pustules occur on upper and lower leaf surfaces often in bands across leaves. As infections mature, pustules become surrounded by necrotic tissues (Figure 8). Rust pustules rupture the leaf surface (epidermis) and powdery rust spores can be rubbed off. Pustules become dark brown to black late in the growing season. The fungus is favored by moderate to cool temperatures and high humidity. The fungus does not overwinter in the Corn Belt, but arrives each season from crops grown in more southern regions.6
Southern Rust
Small, circular, orange-colored pustules occur on upper surfaces, leaf sheaths, and husk leaves. Pustules often are very dense in areas of infected tissues. Pustules break the leaf surface (epidermis) less frequently than common rust. This organism is favored by warm, humid weather. Under severe infection, pustules are common on leaf sheaths and husk leaves.6
Gray Leaf Spot
Gray to tan, rectangular lesions on leaves, leaf sheaths, or husks. Spots are opaque and long (up to 2 inches). Lower leaves are affected first, usually not until after silking. Lesions may have a gray, downy appearance on the underside of leaves where the fungus sporulates.6 The organism thrives in extended periods of warm, overcast days and high humidity. Gray leaf spot has become more prevalent with increased use of reduced tillage and continuous corn.
Management
Regular and timely scouting is important to help prevent corn disease outbreaks. Since much of the energy from photosynthesis is produced by corn leaves immediately surrounding the primary ear, it is important to protect those leaves from foliar diseases especially under conditions that result in high disease pressure. Fields containing foliar diseases should also be scouted for stalk health as the reduction in photosynthesis can predispose corn plants to stalk lodging. Identification of foliar diseases can help determine the need for changes in management practices such as tillage, crop rotation and the selection of more resistant corn products to help reduce disease occurrence next season.
Sources: 1 Brouder, S.M., Camberato, J.J., Casteel, S.N, et al. 2014. Corn and soybean field guide, 2014 edition. ID-179. Purdue University. 2Kleczewski, N. 2014. Anthracnose leaf blight and stalk rot of corn. University of Delaware. 3 OMAFRA. Eyespot (Aurobasidium zeae). Diseases of field crops. Agronomy Guide to Field Crops. Pub 811. p 364. 4 Jackson, T. and Wright, B. 2012. Nebraska corn at elevated risk of Stewart’s wilt and flea beetle damage. University of Nebraska Extension. UNL—Crop Watch. 5 Jackson, T.A., Harveson, R.M., and Vidaver, A.K. 2007. Goss’s bacterial wilt and leaf blight of corn. University of Nebraska –Lincoln. G1675. 6 Physoderma brown spot and stalk rot. Integrated Crop Management. Iowa State University.4 Sweets, L.E. and Wrather, S. 2008. Corn diseases. University of Missouri Extension. Web sources verified 07/21/18. 140706080202
What’s New at Rohrer Seed Solutions? InGrained Micronutrients.
Rohrer Seed Solutions has recently started offering InGrained Micronutrients to our lineup of product offerings. InGrained Micronutrients is a micronutrient package offered by Tracer Minerals. Tracer Minerals made its name in the animal feed market through their feed mineral package offered for livestock. Tracer Minerals recently entered the row crop and small grains market in 2020. They found using their amino acid chelating technology to create a foliar applied micronutrient package started to gaining their customers tonnage and yield.
For the past 17 years, I have always supported making a micronutrient package part of your program. Foliar micronutrients are not designed to fix major deficiencies in the soils of your fields but are formulated to be able to supplement your crop with a boost just when it is needed. This allows us to be able to manipulate the plant into thinking it is having a great day at key developmental stages in the plant’s life cycle. If a foliar micro pack application is part of your business plan, we can do things like add rows around to the ear on corn, adding kernel length, and help with pollination, in times of stress like the damage to the plants in the last hail and wind events. With soybeans micronutrients can help minimize chemical burn, recovery time, adding nodes, and helping the soybean plant hold on to flowers and pods during times of stress. It is the little things that can gain 5-15 bushels. The best plan in using a micronutrient pack like InGrained is to make it part of your plan, and not a knee jerk reaction.
Important Micro Application Periods in a Plants Lifecycle
Corn
(V5 – V8) – number of kernel rows are being determined.
(V10-V15) – number of kernels per row are being determined.
(V14-Tassel Emergence) – stress can majorly affect the length of the ear.
(R2 Blister stage) – stress at this stage can cause the plant to abort kernels.
Soybeans
(Post App) – good time to add a micro and a PGR to aid in recovery from herbicide application and promote additional nodes
(R1 Flowering) - important time to make sure the plant isn’t stressed and had good nutrition.
(R3 pod formation) – Time to spray fungicide, insecticide, along with Micronutrients and PGR. Aids plant to hold on to pods and add additional nodes at top of the plant.
Rohrer Seed Solutions Upcoming News and Updates!
Cover Crop and Small Seeds Update:
As of 6-21-22 the pricing for wheat, barley, and other cover crops are still in a holding pattern. Chris at ProHarvest Seeds, told me they are hoping to release prices for cover crops by the end of the month or early part of July. Wheat prices could drag out to the end of July / early August. Do expect to see a price increase in Cereal Rye, Barley, Rape Seed, and any blend that contain those components. This is a great time to discuss your cover crop needs and placing an order to make sure your needs are covered before supply gets tight. If you ordered last year, you will be hearing from me soon.
Dealer News:
Prairietown Feed Service has recently joined the Rohrer Seed Solutions team as a ProHarvest Seeds cover crop dealer! Prairietown Feed Service is a three-generation family-owned company located in Prairietown, Illinois. They offer Purina feed, fertilizer, seed, crop insurance, and excellent customer service. Give them a call at 618-888-2255 for any of your cover crop needs. Last summer, Cook Farms located in Eldred, IL over by Carrollton also join Rohrer Seed Solutions as a ProHarvest Seeds Cover Crop dealer. Tim Cook along with his son Aaron Cook are local farmers in the Eldred and Carrollton communities where they are known for their love of family, willingness to help their neighbors, and their amazing home cooked customer appreciation breakfasts. If you are needing to talk to someone about your cover crop needs in the Greene County areas, give Tim a call at 217-430-1053.
On A Personal Note:
I want to thank everyone for your business and support in our first year. It has been a huge learning curve adjusting from corporate life to small business entrepreneurship, but it has been a challenge I have accepted head on gratefully. I have been busy with sales, soil testing, operations, planting plots, and now expanding into offering micronutrients. Our families transition to owning our own small business has been busy but I am thankful to not be traveling as often and have more time spent together with my wife, Mandy, and our two kids, Lily, and Hank. Speaking of kids, it has been a blast to get to bring them along with me. It is very fulfilling to hear them ask questions and want to learn about agriculture just as I did with my dad and grandpa on the farm. Firsthand experience is undeniably one of the best avenues to learning I am so glad that I get to do the same with my kids finally.
This past year I have seen success for my customers with the addition of soil testing and Ag recs to assist in improving their soil health and overall operation. RSS held a Cover Crop informational meeting on soil health which was informative and helpful for our customers. We received a lot of positive feedback from that meeting, and we look forward to hosting more informational meetings in the future. It is nice to see so many people looking for ways to improve their soil health and looking for new ways to update their operation with less tillage. It has been my pleasure talking to new farmers, friends, and loyal customers this past year to see how ProHarvest corn and soybeans fit into their operations and provide room for improvement. I have to say, I have my “who we are” speech down pat to the point I may say it in my sleep. I want to assure folks that we are here, and we are going to keep asking to earn your business as a trusted partner on your farm. Fields planted in ProHarvest Seed are looking phenomenal. I am trying to get around and get them all signed so you can look and see that ProHarvest Seeds has a great lineup to fit your farm.
