Detecting late season corn diseases ASAP will help you prioritize fields for harvest. Hybrid maturity and crop residue management should take a backseat to weak stalks. Start by harvesting fields with the weakest stalk to help preserve the quality and quantity of grain that goes into your hopper.
At this time of year, the biggest concerns are stalk rots or fusarium. Warm, moist weather with extended periods of overcast skies and high humidity makes conditions ideal for stalk rot. Later in the season, you might see stalks break or bend below the ear.
Walk fields now and note what you believe is the cause of stalk rot or lodging: fertility, hail, high wind, amount of rainfall, or the genetic predisposition of a hybrid. The cause of stalk rot could affect the seed you purchase or your management practices in 2014. There’s no better time than the present to plan your next crop! Get your seed ordered while the availabilities of all products are at their highest.
Two months ago I posted a blog, encouraging farmers to scout every field for rootworm. Because of the wide variance in planting dates in 2013, it’s important to continually inspect every field – regardless of seed selection – for insect pressure.
With adult corn rootworm becoming active during silking this year, we highly recommend keeping an eye on fields in order to protect yield. Now it is a good time to assess corn rootworm activity: score injury caused by larvae, and monitor adult activity in corn. Late-planted fields or late-flowering hybrids are generally attractive to adult corn rootworm beetles. Silks will still be developing in these fields when older fields have brown or drying silks. Adults may migrate and aggregate in this later-maturing fields.
Also evaluate root injury to better understand the efficacy of your management program. Monitoring over several years will help establish a historical record of how larvae respond to management tactics (e.g., crop rotation, Bt corn, soil insecticides, etc.). One common outcome of severe larval feeding is lodging of corn plants. However, it is important to confirm that feeding from corn rootworm was the cause of lodging and that it did not results from other factors such as strong winds.
To help assess injury, ISU Entomologist Aaron J. Gassmann developed an Interactive Node Injury Scale. Injury assessment made now and field notes taken will help you select seed products for 2014. To prevent corn rootworm damage from reaching devastating levels, plant a portfolio of products.
Continued use of the same rootworm-resistant trait in corn hybrids, an increase of corn-on-corn areas, plus a lack of refuge acres, has caused rootworm resistance to become an issue in some areas. Best management practices to reduce corn rootworm pressure in the future include: crop rotation, trait rotation and respecting the refuge.
Farmers have a chance to see Latham’s new 2014 products this Saturday, Aug. 24, when we host the 5th Annual Latham Freedom of Independence Ride. This year’s ride begins and ends in Lewis & Clark State Park in Onawa. It’s free and open to motorcycles, classic cars and even pickup trucks. For more details, visit our company website lathamseeds.com. Then click on the Freedom Ride icon. Pre-register today, and we’ll see you Saturday on the open road!
Iowa farmers, agronomists, crop consultants and others wanting to get the scoop on corn rootworms are invited to participate in a corn rootworm field day on Thursday, Aug. 8, in Boone, Iowa, at the ISU Field Extension Education Laboratory (FEEL). There is no attendance fee, but preregistration is required as attendance is limited to 50.
Between 8:00 – 10:00 a.m., ISU Extension specialists will perform tissue testing and do rootworm injury assessments on samples brought in by attendees. Receive one-on-one training on using the corn rootworm injury rating scale, as well as discuss corn rootworm (CRW) management options with ISU specialists.
Even if you don’t attend next week’s field day, it’s a good time to be scouting for rootworm beetles and other insects that are actively feeding on corn silks. If silks are clipped to a length of ½” or less, pollen has a hard time landing on the silks and uneven pollination occurs.
Gray leaf spot (early symptoms). (photo from Alison Robertson)
Corn diseases will likely be more prevalent this season due to an excessively wet spring followed by humid summer weather. Plentiful moisture or dew is ideal for most fungal corn diseases. Watch for Gray Leaf Spot, Southern and Common Rust, Northern & Southern Leaf Blight and Eyespot.
Later planted crops can get stressed more easily, which also makes them more prone to insect pressure. It’s likely we’ll see different insect and disease pressure now than we typically would because our corn is not as far along in its development as it would be in late July.
Corn rootworm are strongly attracted to corn during pollination and can trim back silks to the husk. Photo by Marlin E. Rice.
Watch for these insects now that corn is silking: adult corn rootworm beetles, Japanese beetles, western bean cutworm, aphids, corn flea beetle, corn borer and grasshoppers. Consider infection levels, potential economic damage and weather conditions before determining a treatment strategy.
Take good field notes to help you select the right seed for the future. For example, fields with confirmed Goss’s Wilt should be planted to a hybrid that is more resistant to Goss’s wilt in subsequent years. Tillage and crop rotation can also help reduce corn rootworm. Tillage and crop rotation also can help reduce the amount of residue that can harbor bacteria for the next corn crop. For additional information about managing disease or insects, click on the related links below.
With most of the 2013 crop in the ground, it’s time to walk fields. Crops should be scouted within 3 to 5 days of planting and then regularly throughout the growing season. Be on the lookout for: (1) crop emergence; (2) nitrate leaching and (3) insect and disease pressure
It’s a good idea to walk fields within 5 days of planting. Evaluating current stands can indicate whether to replant portions of the field. Notes you take now also could impact your seed buying decisions this fall. Plus, evaluating current stands can help determine if adjustments should be made to your equipment or planter speed next spring.
When checking fields where the corn is more developed, look for signs of nitrogen loss. Iowa State University Nutrient Management Specialist John Sawyer says the best options for sidedressing, in order from most to least preferable, include:
injected anhydrous ammonia, UAN or urea,
broadcast dry ammonium nitrate, ammonium sulfate or urease treated urea,
surface dribbling UAN solution between rows,
broadcast UAN, and
broadcast urea.
Also walk every field for signs of corn rootworm (CRW), regardless of what traits they planted. The corn rootworm hatch is underway, so larvae will soon begin feeding on roots if they aren’t already doing so. Corn development, although delayed, still provides plenty of plant material for the CRW larvae to feast upon. Severe infestation can destroy nodes 4-6, which effect water and nutrient uptake.
Because of the wide variance in planting dates this year, rootworm beetles can move between fields in search of the best “buffet.” A late maturing corn field may attract a large numbers of beetles if neighboring corn stopped producing pollen, for example. Beetles may also move into corn and/or soybean fields that have an abundance of pollen-producing weeds, including volunteer corn, ragweed or foxtails.
Weed control is important for several reasons. Crops have a better chance of reaching optimal yield when they’re not competing with weeds for sunlight, water and nutrients. Plus, controlling weeds helps control corn rootworm populations. The rootworm hatch is underway; expect 50 percent hatch between 684-767 degree days. Click here for current degree day accumulation for corn rootworm provided by the Iowa Environmental Mesonet, ISU Department of Agronomy.
Expect 50 percent hatch between 684-767 degree days. Click here for current degree day accumulation for corn rootworm, courtesy of Iowa Environmental Mesonet, ISU Department of Agronomy.
Cool, wet spring weather delayed corn planting and the corn rootworm hatch, which is largely dependent upon soil temperature. When soil temperatures accumulate between 684-767 degree days, 50 percent of the rootworm hatch occurs.
Although corn is not as far along in its development as it normally is at this time of year, there is still plenty of plant material available to provide a feast for the CRW larvae. It won’t be long before newly hatched larvae begin feeding on corn roots. Severe infestation can destroy nodes 4-6, which effect water and nutrient uptake.
Shortly after larvae begin feeding on roots, adult beetles begin to emerge from fields and begin feeding on pollen, green silks and leaves. The males emerge first, and the females follow about 5 to 7 days later. Mating takes place, and then females will lay eggs toward the end of July through August.
Because of the wide variance in planting dates this year, it will be important to inspect every field – regardless of seed selection. Rootworm beetles can move between fields in search of the best “buffet.” A late maturing corn field may attract a large numbers of beetles if neighboring corn stopped producing pollen, for example. Beetles may also move into corn and/or soybean fields which have an abundance of pollen-producing weeds, including volunteer corn, ragweed or foxtails.
Note areas where corn rootworm damage is the highest and create a plan of action if root injury is high. To help assess injury, ISU Entomologist Aaron J. Gassmann developed an Interactive Node Injury Scale. To help develop an action plan, keep best management practices in mind.
Field notes from 2013 will help you select seed products for 2014. To prevent corn rootworm damage from reaching such devastating levels, plant a portfolio of products. Remember, that in 2104 Latham® Hi‑Tech Hybrids, will offer Agrisure DuracadeTM as another option in the fight against corn rootworm.
Continued use of the same rootworm-resistant trait in corn hybrids, an increase of corn-on-corn areas, plus a lack of refuge acres, has caused rootworm resistance to become an issue in some areas. Best management practices, including rotation, are key to effectively controlling corn rootworm populations.
Northern Corn Rootworm
However, rotation isn’t as simple as it used to be. Farmers can no longer merely rotate between corn and soybeans asthe only effective management strategy. Both the Northern Corn Rootworm and the Western Corn Rootworm have developed methods to counteract the effects of rotation on their life cycles. The Northern species uses a tactic called Extended Diapause that allows its eggs to lay dormant during the time fields are in soybeans. The eggs will then hatch after the field is planted to corn, and the young worms will feed on the corn roots. Adult females of the Western species have actually learned to lay their eggs in soybean fields, thereby allowing them to hatch the following spring when the field is planted to corn. With these changes in what used to be considered the “normal” life cycles of rootworms, managing CRW today requires increased diligence.
Western Corn Rootworm Beetle
Rotating rootworm-resistance traits developed by Monsanto, Syngenta and Dow will help CRW resistance from developing if farmers actually rotate modes of action. One advantage of working with family-owned and independent Latham Hi‑Tech Seeds is that we can help you select the trait packages needed to change up your modes of action. Latham offers the industry’s broadest, deepest seed lineup – which makes it more convenient for farmers to get all their seed needs met.
Using hybrids with more than one rootworm trait like Genuity® SmartStax® may offer another line of defense against CRW. The recent approval of Agrisure Duracade from Syngenta provides another trait in the arsenal to fight CRW; hybrids with Agrisure Duracade are expected to be commercially available in 2014.
Additionally, refuge acres must be planted. Refuge-In-the-Bag (RIB) hybrids available from Latham Hi‑Tech Seeds make compliance simple. Respect the refuge® and it will greatly increase our likelihood of keeping rootworm traits viable for years to come. Rotation helps reduce the risk of resistance. However, planting refuge alone is not enough.
Corn rootworm management is a complex issue and the solution is more than just traits. There are many factors and management options that must be considered:
While perusing some ag chat sites this week, we came across the following questions posted by a Midwest farmer. Today Latham Product Manager Mark Grundmeier answers questions that are top-of-mind with farmers.
Q: Is treating seed corn with VOTiVO® enough to protect the crop from nematodes throughout the growing season? Extremely high numbers of nematodes have been confirmed on one of our farms. We have ordered our corn seed for 2013 treated with VOTiVO. What else should we do to eliminate nematodes, if possible? This is by far the biggest yield robbing problem I have ever seen. I thought Gray Leaf Spot was a big yield robber, but it’s nothing compared to the damage done last year by nematodes. It was deceiving because symptoms all showed signs of drought, even under full irrigation and compaction.
A: One reasonnematodes are difficult to control is because stunted, yellowing, wilting corn is often mistaken for something else, such as drought in this case. Therefore, nematodes often go undetected and the yield-robbing situation multiples – literally.
Nematodes are a growing problem across the Midwest, most likely due to trends of no-till farming. Nematodes are sensitive to soil disturbance, so they tend to thrive in no-till situations. Crop rotation isn’t an effective form of management as corn nematodes also feed on soybeans and grasses. So what is an effective way to manage corn nematodes?
A new management option is using a seed treatment that moves onto the roots to provide early season protection against nematode feeding, says Dr. Greg Tylka from Iowa State University. Poncho®/VOTiVO® seed treatment protects young plants from pests during critical early development stages, leading to healthier root development and stronger stands.
VOTiVO seed treatments act like a barrier, preventing nematodes from attaching to corn roots. Applied directly to the seed, it helps prevent damage to early-season seedlings and roots before pests can strike. Nematicides on the other hand, actually kill the nematodes on contact. Avicta® from Syngenta Seedcare is a nematicide seed treatment that moves on the surface of the root.
Immediate Protection – Systemic agent protects valuable seed from the moment it’s planted
Pest Control – Biological agent creates a living barrier of protection against a wide range of nematodes, including Soybean Cyst, Root Knot and Reniform nematodes
Yield Potential – Promotes healthier root systems and a more vigorous and uniform crop, positively impacting yield
Benefits of Avicta® Brand Seed Treatments:
Avicta Complete Corn is a combination of Avicta nematicide and CruiserMaxx® Corn 250 (Cruiser® 5FS insecticide & Maxim® Quattro fungicide). It is also available with a higher rate of thiamethoxam for enhanced insect protection (0.5 mg ai/seed and 1.25 mg ai/seed respectively).
Provide instant protection against a wide variety of damaging nematode species
Consistently protect against a broad range of early-season insects and disease pathogens
Proven to help increase plant stand, vigor and yield potential
Much of the corn plant’s yield potential is determined in the early growth stages. Avicta Complete Corn provides immediate protection from day one.
The higher the population of nematodes, the greater the chances are that nematodes will break the barrier created by VOTivO. So when extremely high populations of various species of corn nematodes are present, it may be beneficial to use both a seed treatment and a planter-applied nematicide.
Studies by Iowa State University show nematode management products may have a more pronounced beneficial effect in fields with very damaging nematode species and in fields with much greater plant-parasitic nematode population densities.
Managing corn rootworm has become increasingly important as the number of corn-on-corn (c-on-c) acres rises. University research data confirms the real strategy for dealing with high corn rootworm pressure is to use rootworm-traited genetics in addition to other strategies.
Yield is often lost in c-on-c situations due to increased pressure from insects and disease, plus issues related to residue management and soil drainage. Farmers must manage continuous corn acres differently than corn-following-soybeans.
Helping farmers better manage their c-on-c acres is the reason Latham Hi‑Tech Seeds developed the Gladiator group of products. These products combine the best genetics and traits available in the market today to help farmers maximize yields from corn-on-corn acres.
Latham Hi‑Tech Seeds’ 2013 product guide features 33 hybrid seed corn products with 6 different trait combinations for rootworm control in various maturities. Last year we sold out of nearly every bag of our best corn-on-corn products, so order now while supplies last!
We’re also pleased to offer more refuge-in-a-bag (RIB Complete) options than ever before. If you order a Latham® Genuity® SmartStax® hybrid, you’ll receive Poncho 500 and VOTiVO for free. This is a $20 per unit value and will only be offered while supplies last!
Contact your local Latham® representative or call 1-877-GO-LATHAM (1.877.465.2842)
Choose your region:Iowa- Central and Eastern: Kevin MeyerIowa- North Central: Latham HeadquartersIowa- Northeast: Nick BensonIowa- Northwest: Glenn FullerIowa- Central: Nick ColemanIowa- Western: Bart PetersonIowa- Southwest: Larry KrapflMinnesota- Southeast and Iowa Northeast: Craig HaalandMinnesota- South Central and Iowa- North Central: Ryan OhrtmanMinnesota- Southwest: Greg BrandtNebraska- Eastern: John ToftNorth Dakota- Southeast: Gary GeskeSouth Dakota- Notheast: Scott StadheimSouth Dakota- Southeast: Bill EichackerWisconsin- Southwest: Steve Bailie
Corn Rootworms have arrived in Northeast Iowa nearly three weeks prior to normal years. Farmers are urged to be diligent in scouting fields and monitoring pressures in the coming weeks. For more information, tune into Nick Benson’s most recent YouTube video:
