Yield-robbing aphids have started chewing through the Midwestern soybean crop. That has many farmers scouting their fields, with some even applying insecticide to kill the pests.

Close up photo of a soybean aphid

The crop starts to suffer economic damage, or reduced yield potential, when aphid populations reach an average of 250 per plant throughout the entire field. Consider insecticide treatments only if aphids reach economic- threshold level. I recommend spraying with a good insecticide that has three weeks residual. If you’re unsure about whether to treat or not, consult your Latham representative for advice.

Scouting for aphids should begin in late June, intensifying in July and August, especially if soil conditions are dry. Soybean aphids seem to damage late-planted soybeans more than early planted soybeans. Closely scout your fields as conditions across Iowa fields have hit that sweet spot the last few weeks. Reports from our DSMs Brad Beatty of Shellsburg, Iowa and Wayde McNeil of Grinnell, Iowa indicate counts averaging 350 to 400 per plant, well above economic threshold levels.

Scout five locations per 20 acres. At each location, pick five plants well apart form each other. Turn the leaves over to search for aphids; most will concentrate in the plant terminal. Also be conscious of other insects present in the field. Lady beetles, green lacewings and other beneficial insects eat aphids in Iowa soybean fields beginning in mid-June. These insects can help hold down populations in fields that haven’t reached economic threshold levels.

Soybean Aphids collected on the underside of a soybean leaf

Take special note of winged aphids or broad-shouldered nymphs that are beginning to develop wings.  These are nearing adult stage and will soon leave the plant and even the field. An insecticide may not be needed as the population will rapidly decline.

Have soybean aphids invaded fields in your area? Counts even higher then reported by our DSMs? We want to know what the ”Field Position” looks like in your area! Share your story by leaving a comment below!

From emergence through harvest, there are many opportunities to closely observe performance on all of your hybrids.

Now is the time to review early season problems, and note any effects from insects, disease, cultural practices or weather. It’s important to collect additional production information on hybrid performance by soil type as well as abnormal physical characteristics of plants.

From the vegetative to the reproductive growth stages, it’s important to note the uniformity of pollination throughout each field. Uneven plant height can indicate areas of stress in the field and that, along with other yield limiting factors, can change the timing of corn growth and the development, leading to pollination problems.

Watch for conditions that impact moisture uptake, including insects that destroy roots.  Corn Rootworm (CRW) larvae are ferocious root eaters. CRW is thriving this season and pressure can vary from field-to-field. At this time of year, CRW larvae can be found on roots more easily because they are larger. Scout multiple locations within a field for larvae and make notes on other corn soil pests as well.

Collecting information will give you insights as you plan which hybrids are best for your land next year. The primary focus of Latham Hi-Tech Hybrids’ Seed2Soil program is to help you optimize yield potential by planting the right product, in the right location, for the right reasons.

ABOVE: Western Bean Cutworm Larva (Iowa State University)

The Western Bean Cutworm (WBC) has moved into Iowa — and the rest of the Midwest — and it’s making itself at home. The insect first appeared in Iowa in 2000, and has been confirmed in all 99 counties, according to Ag extension experts. Not only are the insects in Iowa, they’re marching east with confirmed cases in Michigan and Ohio.

It is possible to control the pests, but it will take careful scouting and well timed insecticide application. There is no doubt that Western Bean Cutworm is here, and we are going to have to deal with it long-term.

While scouting your fields this season, follow these tips for dealing with Western Bean Cutworm:

• Plants are most vulnerable to cutworm damage just prior to pollination.
• These cutworms feed on silks, tassels, and ears depending on the time of emergence.
• Cutworm feedings cause direct effects on yield, but it also allows other pests to invade wounded plants. Yield losses can reach up to 30-40 percent.
• WBC’s over-winter in the larval stage and emerge in the pupil stage in May and June.
• In mid-July, the pest will be fully developed as an adult. During this time, farmers should scout for moths both in the air and lying in the upper third of the plant.
• Adults will invade during the late whorl stage to begin laying their eggs.
• Scout for clusters of eggs on the upper-third of the plant. Eggs may also be found on the underside of leaves.
• Eggs hatch five days later and WBC larvae begin to feed for the following 3 to 5 weeks.
• In September, the pests return to the soil and begin to prepare for the wintering stage.
• Farmers should follow these general rules of thumb when scouting and determining WBC thresholds in their fields this season. Treat if…
  • Eight percent of plants show presence of egg masses or larvae, and 90-95% of tassels has emerged.
  • If tassels are already emerged at the time of diagnosis, 70-90% of the eggs should be hatched before application of insecticide.
• Timing of insecticide application is critical for control of the WBC. Once the insect tunnels into the silk channel, treatment by insecticide is almost-impossible.

ABOVE: Western Bean Cutworm Moth (Iowa State University)

ABOVE: Western Bean Cutworm eggs (Iowa State University)

For those of you who made the investment in YieldGard-stacked-trait products this year, this information is good news for you! With rising concerns about Western Bean Cutworm problems in fields this year, Monsanto has come out with a Western Bean Cutworm Reassurance Program that will provide financial support in the event of an infestation.

Here’s how the program works.

Farmers must have purchased, and planted, YieldGardVT Triple, YieldGard Corn Borer with Roundup Ready Corn 2, YieldGard Plus or YieldGard Plus with Roundup Ready Corn 2 products between September 1, 2007 and May 31, 2008. At any time in the growing season, if a producer believes an infestation is present and is above the economic threshold, that infestation must be verified. A Crop Scout Log Sheet must be completed by one of the qualified crop scouts including Seed Dealers, Extension Agents, Crop Consultants or Ag-Chem Retailers.

If treatment for the Western Bean Cutworm is necessary, Monsanto will support growers with up to $7 per acre reimbursement to defray the cost of treatment with an approved insecticide. Qualifying insecticides include: Asana, Baythroid, Fury, Capture, Lorsban, Mustang, Mustang Mex, Pounce, ProAxis, Respect, and Warrior. To make a claim, contact your local Latham Dealer to have your claim verified and log sheets completed.

The beginning of July means potato leafhopper season is upon us. Many farmers question how to judge when leafhoppers have reached threshold and when spraying an insecticide is a wise choice. Here are some tips to help you in scouting your fields and arriving at a decision.

Scouting should begin five to seven days after the first cutting is taken from the field and should continue on a weekly basis (or bi-weekly if population counts reach close to threshold on a particular day). Check for stunting in the plants, yellowing of the leaves in a v-shaped pattern beginning at the leaf tip, as well as a “hopper burn” or red edge found on the leaf. This red burn can be easily confused with a Boron deficiency. However, finding the insect can confirm the cause.

The easiest way to scout for these insects is to use a small sweep net. Walk a W-shaped pattern in the field, and take sweep samples at five randomly selected areas. Leafhopper infestations generally begin on the edges of the field so be sure to include these areas in your checks.

To correctly sweep, test each of your five areas following these steps:

• Swing the sweep net in a 180-degree arc so the net rim strikes the top 6 to 8 inches of growth. Each 180-degree arc is one “sweep.”
• Take a sweep from right to left, walk a step, take another sweep from left to right, and so on.
• After taking five sweeps, quickly close the net and count the number of leafhoppers.
• Divide this number by five to get the average, and record these averages for each of the five areas in the field.
• If alfalfa is two or more weeks from harvest, consider applying treatments when leafhopper counts reach five leafhoppers/ sweep (adults and nymphs).
• For fields scheduled to be harvested in 10 days to 2 weeks, consider treating if hopper counts reach 10 leafhoppers/ sweep.

If you’re looking for another solution to help boost yields in your alfalfa fields, ask your Latham representative about the company’s new hybrid alfalfa with the msSunstra® technology. Latham Hi-Tech Forage hybrid alfalfa is shown to outperform conventional varieties by 10-15%. More information about hybrid alfalfa is also available on our website.