Soybean Pests, Tissue Tests, and Discovery Plots too.

News from Your Federated Agronomists | July 24, 2018

Time to Gather Tissue Samples

Now is a great time of year to start tissue sampling in corn and soybean fields. Tissue sampling offers an excellent opportunity to see how well spring fertility plans worked.

Federated Agronomists say there is some window left in the season to tweak some nutritional deficiencies. Foliar products such as VersaMax AC (from Rosen’s) is one such option to address nutrition needs this late in the year.

Tissue sampling can help catch the deficiency before the plants show any outward signs. Once nutrient deficiency shows up in the plants, yields have already been hit, and then it is too late.

However, even if it’s too late to address nutrient deficiencies in this year’s crop, tissue sampling now will help determine what’s needed for next season. It’s an opportunity to determine specific nutrient needs based on good data from the tissue samples.

Federated uses Midwest Laboratories for sample analysis and their turnaround time is five to seven days to get back reports (as in photo above). The tests results show levels of nitrogen, potassium, phosphorous, sulfur, and micronutrients that have been taken up by the plants.

The process of sampling depends on the stage of growth. Here's how to take tissue samples:

On corn prior to tassel, take the newest leaves; once tasseling starts, take samples from the leaves below and opposite the ear.
Soybeans are sampled at the newest trifoliate.
Alfalfa samples should be pulled from the newest leaf blades and petioles one- third of the way down the plant.

Federated Agronomists are available for questions on tissue sampling, or they can come to your fields and take the samples for you.

Scout Soybeans to Beat the Pests

“Scouting for insects in soybeans at this time of year can be quick and painless,” said Jake Hansen, Federated agronomy sales rep in Rush City, but he added, “depending on what you find!” Spider mites and soybean aphids are the two most yield-affecting pests in the Federated areas.

Scouting for spider mites , as small as they are, can be somewhat difficult. “Most times we don't catch them until damage symptoms show up in the crop,” said Hansen. Spider mite damage looks like mild to severe burning, and the beans will turn almost brown.

Watch the weather . . . because the best way to monitor spider mites and prevent crop damage is to monitor the weather, Hansen noted. “Spider mites really thrive in hot, dry weather.” If the weather sets up for a dry spell, keep checking for spider mites. Hansen ventured that “all bets are off for mites this year, but we still have a few weeks left in July and early August for them to show up.”

Keep watch for soybean aphids (pictured above) too, which are much easier to locate by eye when scouting fields. Hansen said, “When heavy pressure is present in a field, you can see yellowing in areas of the field.”

To scout for aphids, look at the new growth and carefully check the uppermost leaves of the plant. Aphids tend to congregate on the underside of the leaf, out of the sun. Look for their distinct shape with small, black cornicles that look like antennae on their hind ends – and they move very slowly. Some aphids have wings, others don’t.

When to treat: The threshold to look for with aphids before considering treatment can be from 200-250 aphids per plant, and is dependent on crop stage and commodity price. Hansen said, “If your count is 150 or above per plant, treatment should be considered because aphids can reproduce rapidly.”

Another factor to consider is the presence of natural predators to aphids. Kevin Carlson, Federated’s senior agronomist, reported late last week that evidence of predators was good. He said, “We’ve been seeing a few aphids, but we are also seeing predators (photo below), which is great. We’re seeing both Asian beetles and parasitic wasps.” Pirate bugs are another predator of aphids.

“However,” said Hansen, “due to the aphid's strong reproduction cycle, common predators to aphids may only depress the population slightly,” so don’t assume all is well. Keep a close eye on the aphid infestation and plan to treat as needed. Talk to your Federated Agronomist about the best treatment options for your farm.

2018 Discovery Plot Tours Feature 'Compact' Format

The 2018 Discovery Plot Tour dates are set. This year’s tours will be “one hour of compact, dynamite information,” said Kevin Carlson, Federated’s senior agronomist. The tours will be packed with valuable news and data that will be worth every grower’s time.

Registration at each event will begin at 10:30 a.m. and the presentation and tour will run from 11 a.m. to noon, with lunch to follow. RSVP to your Federated location and watch for additional details on topics in upcoming Agronomy Updates.

August 27 – Osceola

Craig, Janet & Neil Gustafson Farm

Aug 28 – Rush City

Craig Mold Farm

Aug 29 – Hinckley

Nate Nelson Farm

Aug 30 – Princeton

Larry & Sharon Wilhelm

Sept. 4 – Foley

Doug Lezer Farm

Sept. 5 – Ogilvie

Steffen Farms

Sept. 6 – Albertville

Linneman Farm

Sept 7 – Isanti

Paul & Janet Bostrom