This past week, Latham RSM Steve Bailie found evidence of Armyworm feeding in fields in Southwest Wisconsin. Although most have not been at threshholds high enough to justify treatment, he shares these tips for how to scout for and identify Armyworm feeding in your corn this season.
[youtube]http://www.youtube.com/watch?v=q0lfl1zy6SM[/youtube]
Black cutworm larval activity in Iowa may occur for an extended period of time this season, according to data collected from black cutworm traps in 64 Iowa counties. Fields of higher risk to black cutworm 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. Black cutworm also may cause more damage in fields where corn is planted later.
In a recent Integrated Crop Management News article, Iowa State University Extension entomologists urge corn farmers to scout fields weekly until the corn reaches V5 stage. Examine 50 corn plants in five areas of each field. Look for plants with wilting, leaf discoloration and damage, and those that are either missing or are cut off at the soil surface. Note areas with suspected damage and return later to assess further damage. Larvae can be found by carefully excavating the soil around a damaged plant.
“What if you’ve applied an insecticide mixed with a herbicide when you made your weed control application? Should you still scout for cutworms? ‘The answer is yes,’ says Erin Hodgson, an Iowa State University Extension entomologist, in a recent Wallaces Farmer article. ‘Actually, preventative black cutworm insecticide treatments applied as a tank-mix with herbicides are of questionable worth. Black cutworm is a sporadic pest and therefore every field should be scouted to determine the presence of the insect prior to spraying insecticides. The scouting and rescue treatment approach is the best strategy’.”
To help determine the threshold for treatment, the ISU Corn-Soybean Initiative has developed an Excel spreadsheet to serve as a dynamic decision-making tool.
Many Midwest farmers will wrap up the 2011 planting season this week, but there won’t be much rest for the weary. As soon as seed is in the ground, it’s a good idea to start scouting fields.
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? Seed selection is one of the most important decisions affecting yield. Click here for tips on selecting soybean brands and selecting corn hybrids.
The introduction of new refuge systems in recent years has given growers more options in setting up their refuge. So, to assist farmers in developing the right plan for refuge compliance, the National Corn Growers Association (NCGA) has developed a calculator to help farmers clarify the options and show them how to execute the requirements properly.
Chad Blindauer, Chair of NCGA’s Trade Policy and Biotechnology Action Team said, “Biotechnology is an important part of modern agriculture’s ability to sustainably meet the world’s increasing demands for food, feed and fuel, and its proper stewardship is essential. Given the benefits of Bt products, farmers and trait providers have a duty to keep this technology viable and on the market.”
The calculator includes all commercial Bt products on the market and a trait selection process where farmers can run different planting scenarios on a field-by-field basis. To download the NCGA calculator, click here.
(Source: National Corn Growers Association)
The #1 profit-reducing pest for U.S. soybean farmers is soybean cyst nematode (SCN). In years with adequate to excess rainfall, the short-term effect of SCN on soybean yields may only be a loss in a few bushels per acre. In hot, dry years, yield loss can be 50% or more.
At Latham Hi‑Tech Seeds, we know that SCN resistance is a primary concern for our customers. We’ve dedicated a lot of time, effort and resources toward developing SCN-resistant varieties. We have one of the industry’s largest lineups of cyst-resistant soybean brands. In fact, Latham Seeds was one of the first companies to breed its own lines of CystX.
SCN was first discovered in Iowa in the heart of Latham’s marketing territory in a field in Winnebago County in 1978. The surrounding counties (Kossuth, Humboldt, Webster, Wright, Hancock) have shown to be “hot spots” for SCN development over the years. Typically, the fields in these counties have soils that are classified as Clarion-Nicolet Webster. The cause is still unknown. However, the theory over the years is that because these soils are also prone to Iron Deficiency Chlorosis, they’re more susceptible to SCN.
Due to the microscopic size of soybean cyst nematodes, they’e easily spread. SCN has now been found in every county in Iowa and Illinois, the southern half of Minnesota, Wisconsin, and Michigan, the eastern half of Nebraska, southeastern part of South Dakota, western half of Ohio, northern half of Missouri and parts of most of the soybean-producing states throughout the South. It’s spread by wind and water erosion, farm equipment and all types of animals.
There have been a number of instances where fields in Nebraska, Iowa and Minnesota have been infected with SCN because of the migrating waterfowl. These birds start up north before winter from SCN-infested fields and bring mud on their feet and feathers. That small amount of mud can be loaded with SCN eggs and those eggs can then be deposited in fields as the birds continue their migration south.
As SCN populations have increased, so have the number of cyst-resistant soybean brands. Contact your Latham representative for Latham’s complete lineup of SCN-resistant soybean varieties. To help Iowa soybean growers know their options for SCN resistance, ISU Extension annually publishes a list of SCN-resistant soybean varieties in maturity groups, 0,1,2, and 3. Click here for the 2010 version.
(Source: Wallaces Farmer and Mark Grundmeier, Latham Hi‑Tech Seeds Product Manager)
Good news for soybean growers: according to Iowa State University researchers, there have been very low populations of soybean aphids across the state during the 2010 growing season. What few aphids were in the field were well below threshold levels, indicating yield loss from aphids unlikely. An added benefit to the low soybean aphid populations is fewer multi-colored Asian beetles. A significant predator of the soybean aphid, Asian lady beetles populations grow with the number of soybean aphids present.
If you have troubles with Asian lady beetles in your home or fields this year, however, ISU entomologist Matt O’Neal says prevention is the most important management step. He recommends checking the outside of your home for spaces and cracks as small as 1/8” in size, and removing what lady beetles are present with a vacuum where fabrics allow.
For more tips, read the complete article here.
http://www.iasoybeans.com/egldstnd/article.php?newsletter_id=88&article_id=703
Sources: Iowa Soybean Association Gold Standard and Iowa State University Extension
Soybean cyst nematode (SCN) is a small, plant-parasitic roundworm that attacks the roots of soybeans. SCN is widespread throughout Iowa and surrounding states, and can cause as much as 40% yield loss without symptoms appearing on the soybean plants.
Symptoms to Watch For
A recent Wallaces Farmer article highlighted what symptoms to watch for when checking for SCN in your field. Symptoms are usually not apparent when temperatures are moderate and rainfall is adequate to excessive in the growing season. Symptoms generally begin to appear in mid-July and last through the growing season, and include stunting of plants, yellowing of foliage (not just leaf margins or areas between leaf veins) and mid-day wilting.
Dig, Dig, Dig
The only way to check for SCN is to dig roots, gently remove soil from the roots, and look for the egg-filled, round, white SCN females on the roots (see image). Females are about 
the size of the head of a straight pin or a period at the end of a sentence in a magazine – for most people – females can be seen with the unaided eye. SCN females should be apparent on infected roots through August.
While this is an effective way to identify SCN, it’s also an effective way to see which soybean varieties are controlling nematode reproduction in fields known to be infested. If a soybean variety is effectively controlling the nematode, there should be only 10-20 SCN females present on the roots.
Click here for the full article.
Aphids
A recent e-newsletter from the Iowa Soybean Association reminds growers it’s time to begin monitoring fields for soybean aphids and diseases. As you saw in our recent crop 
report, there have been reports of aphids in Northeast Iowa, but those numbers remain low (about 5% as of July 21). Although aphid numbers may grow in the next two weeks, the impact of the state’s excessive moisture on these numbers remains to be seen.
SDS
Sudden Death Syndrome (SDS) may begin showing up in fields early to mid-August, which is two weeks earlier than normal as a result of the wet soil conditions experienced after planting.
Early symptoms of SDS appear on apparently healthy plants in patches within a field. Scout fields with high-yield potential closely; symptoms will first appear in areas with high moisture. The first symptoms of SDS are interveinal chlorotic (yellow) blotches that progress to large irregular patches. The vein tissue remains green.
White Mold
While it’s a little early for white mold symptoms, according to the article, there’s little doubt white mold will prove a highly problematic for fields again this year. Symptoms will begin showing up after pod set.
Feel free to comment in the field below if you have any questions about the above soybean diseases, and we’ll be in touch with a response shortly.
It’s that time of year again — when corn earworm moths are taking flight throughout the state. Here’s a little information on what to look for as you scout your fields for ear feeding pests like corn earworm.
What to look for
Corn earworms come in a variety of colors: light green, tan, brown, pink or nearly black. The caterpillar’s body is marked with light and dark stripes running lengthwise and the skin texture is coarse due to microscopic spines that cover the surface. Earworms are only in the ear for three to four weeks, but during that short time, they grow to nearly 1.5 inches in length.
Corn earworm can’t live through Iowa’s extreme winters, rather, the moths that lived and 
grew in southern states on either corn or cotton the year before are blown here during May and June each year to re-infest our state.
Because of the tightness of the husk around the ear, feeding is limited to the ear tip, resulting in small larvae or larvae that leave the ear before completing development. The presence of large numbers of eggs on fresh corn silks indicates the potential for damaging populations; eggs hatch in 5 to 7 days following egg laying.
Managing Corn Earworm
The first step to managing corn earworm is choosing a hybrid with built-in control against the pest to limit damage to both the leaf and ear. Early-planted crops are also most likely to escape peak populations of the egg-laying moths. Once larvae enter the corn ears, control with insecticides is difficult but can be effective with exact timing. One should direct insecticidal control towards young larvae that are feeding on the exposed eartips. Since larvae move down the silk channels as soon as they hatch, insecticides become ineffective once they move down from the eartip under the husk.
A recent Wallaces Farmer article shared that in the last two weeks, soybean fields have been reporting cutworm damage – an unusual phenomenon since cutworm is commonly known as a corn insect pest.
Cutworm damage in corn is reported almost every year in Iowa, Erin Hodgson, an ISU Ext
ension entomologist said, but infestations are patchy and sporadic because the cutworm moths have to migrate into Iowa from the Gulf Coast or from the far southern states such as Texas every spring. The moths are attracted to fields where there are young weed seedlings and the cutworm moths lay eggs in these fields. The eggs hatch to produce the larvae (worms, see image) which chew on corn leaves and can cut off young corn plants.
Cutworm damage in soybeans, however, is not typical. Hodgson says entomologists don’t fully understand why cutworms sometimes cause damage to soybean plants. She said there are a few field conditions that may make soybean fields attractive to female cutworm moths:
Determining Cutworm Damage
Hodgson recommends checking 20 consecutive plants in five different areas of your field to determine the percent of cutworm damage. Young cutworms may feed on the soybean stem or leaves, but older larvae can clip off cotyledons. Look for discolored, wilted or dead plants. Cutworms will seek shelter during the day, so dig 2-3 inches down in the soil within a row to try to find them. Consider an insecticide if larvae are less than3/4 inch long and more than 20 percent of plants are damaged or missing.
Click here for the full article.