2018
Evaluating sample-unit size for estimating stink bug abundance on soybean
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Contributor/Checkoff:
Michigan Soybean Promotion Committee
Category:
Sustainable Production
Keywords:
Biotic stressCrop protectionField management Pest
Parent Project:
This is the first year of this project.
Lead Principal Investigator:
Christina DiFonzo, Michigan State University
Co-Principal Investigators:
Project Code:
18-29
Contributing Organization (Checkoff):
Michigan Soybean Promotion Committee
$7,641
Leveraged Funding (Non-Checkoff):
none
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Institution Funded:
Michigan State University
$7,641
Brief Project Summary:

This project focuses on an emerging insect group in soybean, stink bugs. Stink bugs have been an economic (sprayable) pest in the southern U.S. for many years, but they were not an issue in the northern states until recently. First, with warmer weather conditions, stink bug pressure is increasing northward. Second, a new species introduced on the east coast – the brown marmorated stink bug – is now colonizing the Great Lakes region. Finally, in Michigan there is
an interest in growing food grade soybeans, including natto beans for the Japanese market, and such varieties have a low tolerance for stink bug damage.

Anticipating the growing impact in stink bugs, entomologists from the region...

Unique Keywords:
#insects and pests
Information And Results
Final Project Results

Updated February 15, 2019:
1. Comparing two sample units (Sets of 10 vs 25 sweeps) to estimate stink bug numbers in soy: As in 2017, in 2018 the majority of stink bus sampled were Euschistus brown stink bugs. The figure below shows the highest stink bug population, which occurred at the end of August or first week of September, in the seven fields sampled. Each field is represented by a different color bar; the bars show the estimated stink bug population based on taking 10 or 25 sweeps. Regardless of 10 vs 25 sweeps, all data is scaled to and reported as the number of stink bugs per 25 sweeps, because the conventional threshold for stink bug is soybean is 5 per 25 sweeps. In six of seven fields, taking smaller sets of 10 sweeps gave the same estimate of stink bug abundance as taking sets of 25 sweeps. The only exception was a field on the MSU campus, which was much smaller in size than the commercial fields. This data was provided to the University of Minnesota, which is pooling and analyzing it with similar data from other states. Of interest - in contrast to 2017, two fields actually exceeded the threshold for stink bugs. Both fields were in Clinton County, west of St Johns. This was my first time seeing such high numbers in soybean. 2. Stink bugs in food grade soybeans (an extra study to assist Dr. Singh & Dr. Wang). Goal: Determine if certain food grade soybean lines are at greater risk for stink bugs Result: Two food grade trials were sampled. Dr. Manni Singh and Dr. Dechun Wang evaluated agronomic traits of food grade soybeans in 2018. Because food grade beans have a very low tolerance for stink bug damage, I suggested sampling the entries at trial locations in Saginaw and East Lansing, taking five sweeps per plot. The samples were sorted to record the number of stink bugs, Japanese beetle, and bean leaf beetle. As this was an extra project, analysis isn’t done yet.

In preparation for an increase in stink bugs in the future, stink bugs were sampled in Michigan fields and the data pooled with that from other states to identify what species were there and tweak sampling plans in soybeans.

The United Soybean Research Retention policy will display final reports with the project once completed but working files will be purged after three years. And financial information after seven years. All pertinent information is in the final report or if you want more information, please contact the project lead at your state soybean organization or principal investigator listed on the project.