Corn+Soybean Digest Logo

Check out these 3 approaches to making your soybean defoliation estimate more accurate.

July 18, 2022

1 Min Read
11-02 soybean.jpg

The most effective way to make treatments decisions for pests with chewing mouthparts (e.g., Japanese beetle, bean leaf beetle, caterpillars, and grasshoppers) is to estimate defoliation. I’m a “lumper” and don’t try too hard to distinguish feeding by species. Replicated data over multiple growing regions consistently shows economic thresholds for soybean are 30% in the vegetative stages and 20% in the reproductive stages. This threshold applies to the entire field. Sometimes these pest cause significant injury along field margins and perimeter treatments may be more cost effective if practical.

In general, humans tend to over-estimate defoliation and treat more often than necessary. I recommend three different approaches to making your estimates more accurate:

  1. Use this leaflet sampling method summarized in Figure 1 to reduce bias in the field.

  2. Practice estimating leaflet defoliation with Figure 2.

  3. Take this online quiz to calibrate your defoliation estimates.

7-18-22 #1 soybean_defoliator_scouting_plan-600x463.jpg

7-18-22 #2 soybean_defoliation_estimates_panel_0-600x777.jpg

Source: Iowa State Universitywhich is solely responsible for the information provided and is wholly owned by the source. Informa Business Media and all its subsidiaries are not responsible for any of the content contained in this information asset. 

Read more about:

SprayingTechnology
Subscribe to receive top agriculture news
Be informed daily with these free e-newsletters

You May Also Like