U.S. soybean farmers spend approximately $73 million annually to control stink bugs, according to a 2007 grower survey. And those figures don’t include actual crop losses from the widespread, damaging pests.

Actual crop losses are difficult to determine accurately but remain significant, even after multiple insecticide applications.

Jim Heitholt, a crop physiologist with Texas A&M-Commerce and Texas AgriLife Research, coordinates a stink bug team that recently circulated a follow-up survey to see if grower observations have changed drastically since 2007.

The 2010 survey is a lean version of the 2007 survey and asks growers about stink bug spray practices, relative importance of pests, and recommendations for allocation of research dollars. Outcomes of the 2007 survey analysis included the $73 million annual control cost figure which was calculated based on growers claiming spray costs of $7.50 per acre per year. 

The link to the 2010 survey is:

Click here to take survey

In addition to conducting the grower survey, Heitholt’s team has been active for four years and has screened experimental lines for tolerance to stink bug.

“We started the process in late 2006 and early 2007,” Heitholt said. “Prior to that, the United Soybean Board did not have a project specifically geared toward identifying stink bug tolerance.   He said efforts were needed especially in the Mid-South, including the Upper Gulf Coast, Louisiana, and Arkansas.

USB funding

“We submitted a proposal to USB and were fortunate enough to receive funding,” Heitholt said.  The effort included looking at breeding lines from several programs, including lines developed by Glenn Buss at Virginia Tech that were derived from crosses involving Brazilian germplasm and elite Mid-Atlantic lines. 

Heitholt said the screening identified several promising soybean lines for the Mid-South. “After testing 35 lines in three states for three years, four lines proved to have high yield, less stink bug populations, and less seed damage,” he said.

Mo Way, Texas Extension entomologist in Beaumont, with funding from the Texas Soybean Board, “has been looking at stink bug control for years, both for tolerance and for sprays that would work.”  The 2007 survey clearly indicated that growers wanted new insecticides that were more effective on stink bug.  Heitholt also said Roger Leonard and Jeff Davis at the LSU Ag Center are working on the project and have provided excellent data where stink bug infestations have been high.

Greenhouse screening

Allen Knutson, Texas A&M research entomologist and post-doctoral associate Manuel Campos have performed no-choice greenhouse screening for tolerant varieties. “Our project was to determine if several breeding lines had resistance to feeding on pods by green stink bugs,” Knutson said.  “We caged green stink bugs on soybean pods on plants in the greenhouse and allowed them to feed for four days.  We removed the stink bugs and allowed the pods to mature.”

“At maturity (harvest) we examined each seed for feeding punctures and also weighed the seed.  Number of feeding punctures and seed weight was compared to seeds of the same variety not fed upon by stink bugs. Fifteen lines were evaluated and compared to the Brazilian line known to be resistant to stink bug.

 “Three lines were resistant based upon a reduction in feeding punctures, and two lines were resistant based upon a reduction in seed weight loss (they lost the least amount of seed weight when fed upon by stink bugs). These no-choice studies were conducted at the Texas AgriLife Research and Extension Center in Dallas and the results were recently published in the Southwestern Entomologist.

In 2009, the team’s efforts evolved from screening and identification of tolerant lines to breeding resistant varieties with decent yield.  Pengyin Chen from the University of Arkansas and Heitholt crossed these four promising test lines with public varieties adapted to the Mid-South region. The team expects to have enough seed for small-scale field testing in 2011.

Manage expectations

Heitholt is concerned about growers’ high expectations.  “In the 2007 survey, a majority of growers indicated that their expectation for a variety claiming to be tolerant would mean that spraying would not be required,” Heitholt said.

 “Tolerant varieties might be able to withstand low stink bug infestations without insecticides but spraying will likely be needed in situations where stink bug populations are high. We hope the varieties will allow growers to reduce their number of spray applications, but we doubt the tolerant varieties will eliminate spraying completely.  We need to get new lines out and see whether growers notice an improvement.”

Heitholt said tolerance could be bred into transgenic lines, but “we hope to retain a few competitive conventional varieties for growers with alternative marketing strategies.”  The follow-up survey will collect responses through January 2011.   Heitholt’s contact information can be found on the last page of the survey.