Drought conditions experienced during grain fill often increase the potential for stalk rot and lodging problems in corn. When stalk rot occurs late in the season as it often does, it may have little or no direct effect on yield. However, stalk lodging, which results from stalk rot, can have such an impact on harvest losses that many plant pathologists consider stalk rots to be the most significant yield limiting disease of corn.
For a corn plant to remain healthy and free of stalk rot, the plant must produce enough carbohydrates by photosynthesis to keep root cells and pith cells in the stalk alive and enough to meet demands for grain fill. When corn is subjected to drought stress during grain fill, photosynthetic activity is reduced. As a result, the carbohydrate levels available for the developing ear are insufficient. The corn plant responds to this situation by removing carbohydrates from the leaves, stalk, and roots to the developing ear. While this "cannibalization" process ensures a supply of carbohydrates for the developing ear, the removal of carbohydrates results in premature death of pith cells in the stalk and root tissues, which predisposes plants to root and stalk infection by fungi. As plants near maturity, this removal of nutrients from the stalk to the developing grain results in a rapid deterioration of the lower portion of corn plants in drought stressed fields with lower leaves appearing to be nitrogen stressed, brown, and/or dead.
Other plant stresses which increase the likelihood of stalk rot problems include: loss of leaf tissue due to foliar diseases (such as gray leaf spot or northern corn leaf blight), insects, or hail; injury to the root system by insects or chemicals; high levels of nitrogen in relation to potassium; compacted or saturated soils restricting root growth (recent flooding); and high plant populations.
Most hybrids do not begin to show stalk rot symptoms until shortly before physiological maturity. It is difficult to distinguish between stalk rots caused by different fungi because two or more fungi may be involved. Similarly, certain insects such as European corn borer often act in concert with fungal pathogens to cause stalk rot. Although a number of different fungal pathogens cause stalk rots, the three most important in Ohio are Gibberella, Collectotrichum (anthracnose), and Fusarium. For more information on stalk rot in corn, consult the OSU Plant Pathology web site "Ohio Field Crop Diseases" (http://www.oardc.ohio-state.edu/ohiofieldcropdisease/) for more details and pictures of the disease symptoms associated with these pathogens.
The presence of stalk rots in corn may not always result in stalk lodging, especially if the affected crop is harvested promptly. It’s not uncommon to walk corn fields where nearly every plant is upright yet nearly every plant is also showing stalk rot symptoms. Many hybrids have excellent rind strength, which contributes to plant standability even when the internal plant tissue has rotted or started to rot. However, strong rinds will not prevent lodging if harvest is delayed and the crop is subjected to weathering, e.g. strong winds and heavy rains.
A symptom common to all stalk rots is the deterioration of the inner stalk tissues so that one or more of the inner nodes can easily be compressed when squeezing the stalk between thumb and finger. It is possible by using this "squeeze test" to assess potential lodging if harvesting is not done promptly. The "push" test is another way to predict lodging. Push the stalks at the ear level, 6 to 8 inches from the vertical. If the stalk breaks between the ear and the lowest node, stalk rot is usually present. To minimize losses from stalk lodging, avoid harvest delays. Identify fields which are at greatest risk and harvest these fields first. Fields which experienced drought stress, defoliation due to hail, foliar disease injury, etc. would be prime candidates for early harvest.
The week of September 11 calls for above normal temperatures and below normal rainfall. Normals highs are in the 70s and lows in the 50s. Expect most of the week to see highs in the 80s and lows in the 50s and 60s. The next chance for a little rain will come late Friday or Saturday but most places will see less than 0.25 inches. Normal rainfall is about 0.7 inches.
The week of September 17 calls for a return to more typical weather with some rain early to mid week and temperatures turning below normal by about 2-5 degrees. Rainfall will be near to below normal in the 0.4 to 0.8 inch range.
The rest of September will average slightly warmer than normal with normal to below normal rainfall.
The National Weather Service Ohio River Forecast Center has an update on Stress Degree Days for Corn for Ohio.
Year SDDs % of trend line yield
1936 471 74%
2012 374 ??%
1934 373 76%
1988 358 66%
2002 259 65%
1983 249 80%
100% of trend line are forecast at SDDs of 140.
Clearly, other things like drought versus non-drought, disease etc play a role but high maximum temperatures play an important role in corn crop results. Generally speaking when SDDs are 100 degree above 140, crop production is typically 60-80% of normal. We may have not seen as much loss in the Great Depression years due to factors such as technology was not as much of a factor and yields were much lower so the spread may not have been as much. It seems reasonable to conclude with today's conditions every 100 degrees above 140 means a reduction of 10-20%. A more in depth study could provide a more detailed relationship.
Corn, soybeans and hogs are important to farmers in the western part of Ohio, and so are the research and development projects arising from OARDC's Western Agricultural Research Station. The Western Agricultural Research Station is a 428-acre research facility located 4 miles north of South Charleston, Ohio, that was established in 1958. The predominant soil types include Brookston silty clay loam, Crosby silt loam, Miami silt loam, and Celina silt loam, which are typical of western Ohio. The Western Station is unique in the fact that it supports an intensive agronomic and specialty crop program and maintains a farrow to finish swine facility: http://www.oardc.osu.edu/branches/branchinfo.asp?id=9.
The Ohio Agricultural Research & Development Center (OARDC), Ohio State University Western Ag Research Station, S. Charleston, OH is accepting applications for a Research Assistant 2 and Agricultural Technician I. Job description, qualifications and application online: www.jobs.osu.edu.
· Research Assistant 2 #366327
· Ag Tech I #370432
Requires successful completion of a background check. To build a diverse workforce Ohio State encourages applications from individuals with disabilities, minorities, veterans, and women. EEO/AA employer.
Ohio State University Extension , The Ohio Department of Agriculture (ODA), and USDA’s Farm Service Agency (FSA) will host a series of meetings throughout the state in September to provide crop and livestock farmers with livestock feeding and agronomic information as well outline access to available relief resources.
In July, Governor John R. Kasich signed Executive Order 2012-11K, instructing state agencies to work with Ohio’s farmers to minimize the potential environmental and economic impact of an agricultural drought. As part of the order, ODA was instructed to hold a series of educational meetings to discuss forage management, water availability, heat stress on livestock, mitigation strategies and other drought-related topics.
The meetings will include officials from ODA, livestock and crop specialists from Ohio State University Extension and FSA personnel. The public will have the opportunity to talk with experts and ask questions at the following meetings:
September 10, 2012 5:30pm – 8:00 p.m., Ohio Department of Agriculture – Bromfield Administration Building (Auditorium), 8995 East Main St., Reynoldsburg, Ohio
September 12, 2012 5:30pm – 8:00 p.m., Heidelberg University – Campus Center Building (Room 120 and “The Great Hall”), 310 E. Market St., Tiffin, Ohio
September 17, 2012 5:30pm – 8:00 p.m., OARDC Wooster Campus– Fisher Auditorium, 1680 Madison Ave., Wooster, Ohio.
September 20, 2012 5:30pm – 8:00 p.m., Greenville High school–Cafeteria (Room106), 100 Green Wave Way, Greenville, Ohio 45331
September 25, 2012 5:30pm – 8:00 p.m., Ohio University Zanesville & Zane State College
– Campus Center Building (Rooms T430 and 431), 1425 Newark Rd., Zanesville, Ohio
September 27, 2012 5:30pm – 8:00 p.m., Hocking College– John Light Hall (Room 195), 3301 Hocking Parkway, Nelsonville, Ohio
Additional meetings will be announced as they are scheduled.
The OSU Extension Agronomic Crops Team will again this year offer the FSR CCA College so that those CCAs attending or working at the Farm Science Review can earn continuing education credits. Again this year the FSR CCA College will be a little different and will not be just one day, but all three days of the Farm Science Review is a CCA College. There are several CEU opportunities all over the grounds and all three days – September 18, 19 & 20:
· At the Gwynne Conservation area will be Soil & Water CEUs
· We’ll have Crop Production CEUs at the Small Farm Center
· At the Agronomy Plots between the East End of the Exhibit Area and the public parking is this years display of Crop Management, Soil & Water and Pest Management demonstration plots – all available for CEUs. Agronomic Crops state specialists and county field specialists will be on hand to discuss this year’s problems and talk about opportunities for future crop yield increases – for crop consultants and for growers
Watch for the “Are You Good Enough to be a CCA?” clipboards posted at each venue. On the clipboard will be sign in sheet; sign in at the time and date of your program and CEUs will be awarded.
· See all the FSR CCA College opportunities on the Agronomic Crops Team website under links or: http://go.osu.edu/2012FSRCCACollege.
· Buy Farm Science Review tickets at your local County Extension office for $5 or at the gate for $8. For more information on the Farm Science Review: http://fsr.osu.edu.
· Also, there is a new Farm Science Review application for your smartphone, search the iTunes app store for Farm Science Review. This includes maps, schedules, speakers, times – it’s all there!
- Mike Gastier (Huron),
- Glen Arnold (Nutrient Management Field Specialist),
- Rob Leeds (Delaware),
- Rory Lewandowski (Wayne),
- Sam Custer (Darke),
- Tony Nye (Clinton),
- Debbie Brown (Shelby),
- Nathan Douridas (FSR Farm Manager),
- Ron Hammond (Entomology),
- Andy Michel (Entomology),
- Ed Lentz (Hancock),
- Adam Shepard (Fayette),
- Matt Davis (Northwest ARS Manager),
- Rich Minyo (Corn & Wheat Performance Trials),
- Bruce Clevenger (Defiance),
- Mark Loux (Weed Science),
- Suzanne Mills-Wasniak (Montgomery),
- Amanda Douridas (Champaign),
- David Dugan (Adams, Brown, Highland)