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.
Walking fields and noting where there is weed and insect pressure will help you determine what you select seed products in the future.
“Be prepared” is the Boy Scout motto. Like a good Scout, farmers across the Midwest should be prepared for the unexpected this season as pests aren’t following their typical developmental patterns. Corn and soybean plant development is later than normal, so they could be more susceptible to insect and disease pressure as pests prey on weaker plants.
We haven’t seen much insect pressure yet this year, and that could be for a couple of different reasons. First of all, the wet spring delayed planting and spraying. Many farmers have gone straight from planting and tillage to spraying and haying. Not many people have had the time to walk their fields and really take a close look for signs of insect and disease pressure. Secondly, just as crop development is delayed, so is insect development. We know the corn rootworm hatch was delayed. We also know Japanese Beetles have been delayed.
Just because the weather slowed them down, don’t count them out! The Japanese Beetleis becoming a more common pest for both corn and soybean crops. These voracious eaters literally eat anything that’s green. They seem to prefer the leaf tissue between the veins of soybean leaves and the soft silks of corn plants. Both activities can result in significant yield loss, so it’s important to scout for Japanese Beetles.
Also watch for Bean Leaf Beetles, which have adapted to winter by protecting themselves in leaf litter. Although overwintering beetles rarely cause economic damage, their presence may be an indicator of building first and second generations later in the season. While feeding on young soybean seedlings, these beetles have been known to infest them with disease that leads to Bean Pod Mottle Virus.
Another insect that could do some damage this season are corn rootworm. Because of the wide variance in planting dates in 2013, rootworm beetles may 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. Rootworm beetles may also move into corn and/or soybean fields that have an abundance of pollen-producing weeds, including volunteer corn, ragweed or foxtails. Controlling weeds will also help control corn rootworm populations.
In addition to corn rootworm, black cutworm could a larger problem this year as they’re known to cause more damage in fields where corn is planted later. Fields of higher risk also include those that are poorly drained and low lying; those next to areas of natural vegetation; and those that are weedy or have reduced tillage.
Walking fields and noting where there is both weed and insect pressure will help farmers determine an action plan for the future, too. It will help you determine if you need to change modes of action in future years. Remember, family-owned Latham Hi‑Tech Seeds offers the industry’s broadest product portfolio. New for 2014 planting are Latham® Hi‑Tech Hybrids featuring Artesian and DroughtGard technologies. We also will offer a complete portfolio of Refuge Made Simple products including corn hybrids with Genuity® SmartStax, VT2 and VT3, plus Agrisure 3122 E-Z Refuge. For more details, contact your local Latham® representative or call the Latham office at 1-877-GO-LATHAM.
This spring has been anything but normal. We are currently sitting at 67% of corn planted and 39% of soybeans planted. With the higher-than-average number of unplanted acres, we could be looking at a contender for 2013 prevent plant numbers. Although this has been tough for many of our farmers and dealers throughout the growing season, there has been a positive response for corn and soybean markets. With a few more days of drier weather, Latham Country could make a lot of #plant19 progress.
We have received many questions this spring about when it is time to switch soybean varieties. The good news is soybeans are not as picky about maturity and delayed planting as corn. The typical maturity range for your area can be planted up to Mid-June without any worries. For those in the northern part of the territory, that date is closer to Early June. Its not a good idea to jump down more than 0.5 maturity group for your area. Remember soybeans mature based on night-length and not heat units, so they will make it to maturity, but the full season maturity encourages them to accumulate more nodes (i.e. more pods) before fully switching to seedfill.
Rules of Thumb on Later Planting:
Each 4 days later in planting date causes 1 day later maturity. One month later planting causes 1 week later maturity.
Farmers should not switch to a soybean variety that is out of their maturity zone.
For later planting, use narrower rows and slightly higher seeding rates whenever possible. We need to get canopy coverage as soon as possible.
When planting between June 1-10, expect a yield loss of one half bushel per day. When planting between June 11-20, expect an additional yield loss of one bushel per day.
Yield predictions for planting July 1 or later are extremely variable depending on growing conditions and frost date.
Early Season Tissue Sampling Helps Detect Deficiencies
Tissue sampling has become very popular in recent years as it more accurately represents plant nutrition. That’s why tissue samples should be taken as early in the season as possible to properly detect nutrient deficiencies and make adjustments during the growing season.
For accurate results, avoid testing plants that show severe signs of stress from factors not related to nutrients. This includes damage from insects, drought or flooding, temperature, chemicals or machinery. Also be sure to test normal plants in addition to affected plants in the same stage of growth.
When testing alfalfa plants from beginning stages until the first flower, it’s important to sample from the top six inches of the plant. Collect about 35 samples. When sampling alfalfa closer to or at harvest for comparison, test about 25 whole plants. Collecting soil samples simultaneously can be helpful when paired with the plant analysis to identify nutrient deficiencies, toxicities and imbalances. Take soil samples, at a six- or seven-inch depth, from the same areas where plant samples were collected.
Once samples have been collected, remove foreign particles like dirt but do so without washing the plant. Place the samples in a paper bag or a large envelope to help prevent them from developing mold during shipping. Soil samples also may be placed in a waterproof container with a correlating label to the field and tissue sample with which it was taken.
Depending on the lab you use, some reports for plant samples will reveal the concentration of N, P, K, Ca, Mg, S, Zn, Mn, B, Cu, Fe, Al, and Na within the plant. Soil samples submitted with the plant sample will be analyzed for pH, organic matter, P, K as well as special soil test results. Nutrient levels will also be interpreted for soil and plant samples to identify any nutrient issues and potentially offer recommendations. It’s important to note that nutrients can then be soil, seed and foliar applied.
The ability to apply timely nutrition and reach new yield levels is so exciting! Experiment on your farm.
While some Midwest farmers will get the opportunity to reenter their fields this week, there won’t be much rest for the weary. With some seed already in the ground, it’s important to start scouting those fields now.
Post-planting is an ideal time to begin scouting one’s crops. Many soilborne pathogens strike as soon as the seed begins to take on water; others strike young seedlings. Because seeds can germinate quickly and emerge in 3 – 5 days, it’s not too soon to start walking your fields.
Check plant populations, evaluate stands and be on the lookout for early summer diseases. Is there a germination problem? Do you see effects of chilling or crusting?
Assessing your situation ASAP will allow you to formulate a plan while there’s still plenty of time to implement it. You could replant in parts or in all of a field now, so you can attain the yields and returns you want this fall. Information on corn replanting decisions is available from www.agronext.iastate.edu/corn. Click on the “Planting” topic, then click on the “Replant Decision Aid Calculator” tab and use that tool and related information to help make a replant decision. For a resource on soybean replanting decisions, go to www.extension.iastate.edu/publications/pm1851.pdf.
Another benefit of evaluating current stands is to help you determine what adjustments should be made before planting next year’s crop: Do you need to adjust your planter settings or your planting speed?
Once you get past the mechanical issues, look at the disease pressure. If soybeans are damping off, perhaps next season you should opt for seed-applied fungicides? Do you need to pay closer attention to a particular soybean brand or corn hybrid’s disease rating?
Better planting equipment, improved soybean genetics and technology advancements such as seed treatments and weed control systems have moved soybean planting dates earlier in recent years. Last year 34% of Iowa’s soybean crop was planted by early May; this year only 1% of Iowa’s soybean acres are planted as of May 13.
Although there is a correlation to higher yield potential with earlier planting dates, it’s important to remember that soybeans respond favorably to early-planting datesif soil conditions are ideal for planting. Conditions weren’t fit for planting soybeans in late April or early May.
One silver lining in the delayed soybean planting is that soil temperatures have warmed. We recommend planting soybeans when soil temperatures are about 60 degrees, and soil temperatures were averaging only in the low 60s around May 15.
Planting into a field that is too wet or too cold early in the season will reduce emergence and plant population, which most often leads to reduced yield. Remember, planting soybeans in warm but wet soils can also have a detrimental impact on yield. Patience will continue to be key this planting season!
To help provide “picket fence stands,” corn growers must make proper planter adjustments. It’s also important to match the planter speed to field conditions and to avoid planting seeds in extremely poor soil conditions.
Planting in soils that are too wet can lead to sidewall compaction. The under-developed root systems resulting from the compaction are often confined in a flat plane within the furrow trench. Planting in too wet of soil, especially with coulters, allows sticky soil to build up on gauge wheels resulting in planting depth differences.
Shallow planting places seed in differing soil moisture levels and can result in differing emergence dates. Shallow planting also can lead to a shallow secondary root system. “Rootless corn” may result, or plant development may be greatly delayed compared to neighboring plants.
Failure to close the furrow is usually caused by poor soil conditions, improper closing wheels for field conditions, incorrect down pressure, or planting in sod. Worn or improperly adjusted planter parts can cause or aggravate all the previously mentioned problems.
Make sure your planter does all its jobs properly: open the seed furrow without sidewall compaction; place seeds at a uniform depth; and close the seed slot without compaction. Stop the planter frequently and physically check to ensure you’re getting uniform seed depth and good seed-to-soil contact. Although it will take a few extra minutes in the spring, you’ll be glad you did when it’s time to harvest those extra bushels come fall!
Consider Traits & Chemistries in Your Crop Rotation
A soybean-corn crop rotation allows farmers to spread out spring and summer fieldwork and provides a larger window for harvest. Plus, a soybean-corn rotation can lead to energy savings during production and when handling, drying and conditioning of stored grain, according to recent issue of “Advance” published by the ISA On-Farm Network.
“Studies show us that corn yields are higher following soybeans. The advantage of a soybean-corn rotation still centers on yield. The positive impact is probably due to several factors,” says Ed Anderson, Iowa Soybean Association senior director of supply and production systems. “Soybeans break disease, insect and weed cycles and provide a nitrogen credit for corn the following year.
However, it’s no longer enough for farmers to merely rotate crops. Farmers also must rotate between herbicide chemistries, as well as hybrid/variety traits. Rotating between various herbicide traits is important from the standpoint of reducing weed resistance. It also has been proven that it helps in overall herbicide performance.
Rotating traits, especially insect resistance traits in corn, is especially important for the same reasons – to decrease the risk of insects becoming resistant to those traits and also to improve overall trait performance. As newer traits become commercially available in soybeans, the same will be true. We will need to be good stewards of these traits and rotate them whenever possible!
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.
Even though spring planting has been delayed by unseasonably wet and cold weather, there’s no need for corn farmers within the Upper Midwest to push the “panic” button. We’re still within the ideal planting window, so work your crop plan.
Research shows that hybrids adjust to planting dates.Adapted full season corn hybrids can compensate somewhat for later plantings. As planting is delayed, hybrids shorten the time between planting and silking. Full-season hybrids almost always outperform short season hybrids, so farmers really don’t need to consider switching maturities until May 25.
Let soil temperatures and soil conditions – not the calendar – dictate planting dates. At this point, fields are not yet fit for planting. Your yield potential will be more negatively affected by planting in wet soils than waiting even a couple of weeks for better conditions. On average, farmers will lose about half of a bushel/acre per day due to delayed planting. Research shows farmers will lose more yield if crop is planted into less than ideal conditions, so we encourage you to wait for soils to warm up and dry out.
Corn planted into wet soils will be prone to problems throughout the growing season such as: stunted plant growth; slow infiltration of water and/or ponding; high surface runoff under normal or light rainfall; poor root system development, or rootless corn; and even nutrient deficiency. Potassium deficiency is caused by corn roots not being able to take up potassium from compacted soils.
REMEMBER: The majority of yield is determined during planting. “Patience” is key right now. Good things come to those who wait for the right seedbed conditions!
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.
