Clipped or missing plants could be a sign there’s a new scavenger in your emerging soybean fields, according to a recent article in Wallaces Farmer.  Isopods – a.k.a. woodlice, pillbugs, sowbugs and roly-polies – are a new early-season soybean pest in the Midwest.

No-till fields can be especially attractive to isopods as the crop residue helps provide high levels of moisture needed for their survival. Because all life stages breathe through gills, isopods must live in habitats with high humidity.

These omnivores scavenge on dead and decaying plant or animal matter but will also eat live, young plants. Feeding is often done at night as isopods are skittish.

Although small in size (adults are three-eights inches long), isopods can do big damage.  Some areas in Kansas and Nebraska have already experienced economically damaging levels of isopods that required replanting.

Management is difficult as these terrestrial crustaceans are naturally protected by armor-like plates on their backs.  Seed treatments and foliar insecticides have been ineffective. To minimize overwintering populations and to reduce soil moisture in the spring, Extension crop specialists are recommending to till heavily infested areas every other year.  Click here for more information, including photos of affected seeds and seedlings.

Wallaces Farmer shared an article recently including points to consider when collecting samples for nematodes in strip trials. The article stated many people have asked how to properly collect nematode samples from strip trials of corn treated with new seed-treatment nematicide products – the two most common being Avicta Complete Corn and Votivo.

Greg Tylka, an Iowa State University Extension plant pathologist and nematode expert said to consider the following when gathering samples for nematodes in strip trials.

• The new seed-treatment nematicides provide early season, not season-long, nematode protection; duration of protection is not specified or known. Differences in nematode numbers due to the nematicides may occur early in the season (four to six weeks after planting), when the nematicides are having an effect, and not later in the growing season.

• There are many different species of corn nematodes and they vary in their generation times. For example, the root lesion nematode can complete a generation in 30 to 50 days; dagger nematode will have only one generation in an entire growing season. The likelihood of detecting a difference in nematode numbers among treatments depends on what nematodes are present in the field and when the nematode samples are taken.

• Soil and root samples should be collected to assess nematode numbers. Roots are needed because some plant-parasitic nematodes feed almost entirely inside corn roots during the growing season; their numbers can be deceivingly low in the soil. Whole plants can be submitted if plants are relatively small; otherwise, root balls should be submitted. Collect several plants or root balls from each sampling area or “plot” so nematodes can be extracted from root tissue.

• It is difficult to determine where to collect samples from strips. One suggested method is to collect 20 of the 12-inch-deep soil cores and a few plants or root-balls from a four- or eight-row wide by 25- to 50-foot-long area of each strip. The sampled area will serve somewhat like a plot for each treatment.

• Collect sets of samples from “plots” in a straight line (or transect) across the various treatments in the strips. Ideal places to locate the transects in the field include: 1) areas suspected of having damaging nematode populations, 2) areas where there is poor corn growth and 3) areas with uniform soil conditions (and hopefully uniform nematode populations).

• Soils with higher than 70% sand content can be infested with needle and sting nematodes, and these nematodes can be difficult to recover in the middle of the growing season. If needle and sting nematode infestations are suspected, you should collect soil samples from strip trials within the first four to eight weeks of the season. With these nematodes, there is no need to collect root samples as both species exist exclusively in the soil. Collect several plants or root balls from each sampling area or “plot” so nematodes can be extracted from root tissue.

Click here for the full article. Tylka will be providing additional information on corn and soybean nematodes at the Latham Country Fair in Alexander, Iowa, July 30. Please watch the blog for more details!

If you have any questions about how to sample strip trials for corn nematodes, simply click “Leave a comment” and comment in the field box we’ll answer your question shortly.

As we mentioned last week in our post on corn nematodes, this year’s early planting brought the opportunity and challenge of scouting crops early. Early scouting helps ensure you can identify and resolve any challenges before they become a bigger issue for your fields. A recent article in Wallaces Farmer included information about specific pests you should watch for this season.

Early growth stage pests to keep an eye out for this year include armyworms, black cutworms, white grubs and wireworms. Also keep an eye out for early signs of bean leaf beetle in soybeans.

The black cutworm is another pest that may try to visit your fields this year. The cutworm leaves small shot holes in corn leaves and when it grows to a half-inch long, can cut the plant. Stand loss or irregular stands may result. Significant flights of black cutworms have been reported in Missouri, with the very first capture taking place in mid-March, proving it will be a threat to some regions this year.

Grub species, such as the Japanese Beetle are common pests to both corn and soybeans. While they’re common in Illinois and the eastern Corn Belt, the article said they can range into Nebraska, as well. While a common pest, they should still be taken seriously as people have reported adult beetles defoliating soybeans.

Please let us know if you have any questions about how to identify or manage these pests.

Click here to read the full article.

We’ve just experienced one of the most amazing months for crop planting in recent memory. The National Ag Statistics Service released a report April 25 stating corn planting in the upper Midwest is significantly ahead of both the 2009 planting and the five-year average.

One benefit of early planting is that farmers should have more time this spring to check their fields for various pests. For this article, I’d like to focus on Corn Nematodes in particular, as these microscopic roundworms have been flying under the radar of farmers and crop scouts for years.

Like Soybean Cyst Nematodes (SCN) in soybean fields, Corn Nematodes are capable of reducing corn yields without showing any particular above-ground symptoms.  If you suspect that you are losing bushels from this pest, consider taking some soil samples to determine which nematode species is present in your field and at what level they are present.

The best time to sample for corn nematodes is 4 to 6 weeks after planting.  Most university labs and even several private labs can run a corn nematode analysis on soil samples.  To borrow a line from the SCN awareness group, “Take the Test & Beat the Pest!”

Taking soil samples now will help detect Soybean Cyst Nematodes (SCN) but also will help farmers manage a SCN problem. If need be, Iowa State University Plant Pathologist Greg Tylka recommends that farmers switch to soybean brands that are SCN resistant.

“That single decision could pay dividends to the tune of 10, 15, 20 or more bushels per acre in yield by knowing if you have SCN and managing it properly with resistant soybean varieties,” said Tylka, last week in a news release distributed by the Iowa Soybean Association.

Tylka says management does take effort, but it is well worth it. “You can’t go by what you’re hearing your neighbors say is happening in their fields,” he says. “(Even) two fields on the same farm could be completely different.”

To hear Tylka discuss SCN in more detail, visit ISA’s Production Research Web site to listen to this podcast and others. You can also hear Tylka discuss both corn and soybean nematodes on July 30 during a special farm tour at Latham Hi‑Tech Seeds’ headquarters in Alexander, Iowa.

CystX for broad-based SCN resistance: CystX provides broad-based SCN resistance and significant cyst soil population reductions. CystX varieties show an observed tolerance to Sudden Death Syndrome (SDS), have healthier root systems and possibly give higher test weights. For more information, click here.