Dectes Stem Borer in Soybeans

November 17, 2014 in Uncategorized

Joanne Whalen, Extension IPM Specialist
Phillip Sylvester, Kent County Agricultural Extension Agent

With the delayed harvest conditions this fall, we have received a number of calls regarding lodged soybean plants that are not being picked up by the combine. Although it is most common and severe in full season soybeans, we are also seeing a recent increase in lodging in double crop soybeans. As everyone knows, lodging can be caused by many agronomic and weather related factors. However, if you are seeing plants laying on the ground after harvest or lodging in your field before harvest, you should consider the Dectes Stem Borer as a potential cause of this damage. In Delaware, this insect has been a pest of soybeans since the early 1980s. Although some have asked if we are seeing an expansion in the range of infestation in Delaware, it may be more related to the increase in full season soybean acres planted in 2013 and 2014. In many cases, low levels are probably present in many fields but in certain years, especially under delayed fall harvest, we tend to see and hear about more lodging losses. We do know that this insect is more of a problem in areas and fields that are not rotated i.e. continuous soybean production.

Insecticide applications have generally not been successful in significantly reducing the damage caused by this insect pest. The only developmental stage that can be targeted for control is the adult beetle because the larvae never leave the host plant. Temporary reductions in beetle populations have been achieved with an insecticide application; however, because adult emergence occurs over a large window, fields can be quickly re-infested. There has also been mixed results with multiple insecticide applications. In addition, the research from other areas of the US indicates that adult control is not highly correlated with levels of larval infestation at the end of the season. So that leaves cultural control options as you make plans for the 2015 season.

Although cultural control practices will not provide 100% control, research results from Delaware and other regions have indicated that with the adoption of a combination of the following cultural control strategies, the risk of yield loss from the DSB can be reduced.

  • Early/Timely Harvest: Early or timely harvest has been shown to significantly reduce lodging losses. Sampling techniques and field history can be used to identify fields with high infestations of DSB that should be harvested in a timely manner.
  • Crop Rotation: Adult DSB are not considered “strong” fliers so crop rotation can help in reducing populations. However, unless a field is isolated or this approach is adopted area wide, this strategy may not be effective in reducing DSB populations in regions with significant acreage planted in soybeans.
  • Fall Plowing: Research has indicated that plowing stubble lead to a reduction of adult beetle emergence in the summer.
  • Weed Control: Giant ragweed, common cocklebur and wild sunflowers are alternative host plants for DSB. Therefore, weed control within and around the perimeter of fields is important.
  • Row Spacing: In general, the severity of an infestation or number of lodged plants does not appear to be affected by row spacing. However, in fields planted in narrow rows, lodging losses may be reduced because the lodged plants are held up to some degree by the surrounding plants.
  • Variety Selection: Experience in Delaware has indicated that lodging loss is typically more severe in shorter season varieties (Group II, III and early Group IV’s). Soybean Cyst Nematode (SCN) resistant varieties may have fewer lodged plants compared to SCN susceptible varieties. Field sampling has confirmed that the larvae will infest most varieties; however, some are more prone to lodging, especially in drought situations.

For more information on the identification and biology of Dectes Stem Borer, please see the following link: http://extension.udel.edu/ag/2012/05/22/dectes-stem-borer-management-in-soybeans/

IMG_20141111_082438_272 - Copy

Dectes Stem Borer larva in soybean stem. Photo by P. Sylvester, UD.

2014 Delaware Hybrid Field Corn Performance Trials

November 17, 2014 in Uncategorized

The 2014 Delaware Hybrid Field Corn Performance Trials are now available online: http://extension.udel.edu/ag/field-crop-resources/variety-trials-corn-hybrids-small-grains-soybeans/

Upcoming Meetings: 2014 Farm Bill Training

November 7, 2014 in Uncategorized

Farm Bill Training page 4

Farm Bill Training page 3

Farm Bill Training page 2

Farm Bill Training page 1

2014 Mid-Atlantic Crop Mangaement School: Register Now!

October 13, 2014 in Uncategorized

The 2014 Mid-Atlantic Crop Management School will be held November 18-20 in Ocean City, Maryland. The program and registration can be found on the following website: https://www.psla.umd.edu/extension/md-crops

The early-bird registration fee is due by October 31, 2014.

This school is designed for anyone interested in crop management issues, including

  • agronomists
  • crop consultants
  • extension educators
  • farmers and farm managers
  • pesticide dealers, distributors
  • seed and agrichemical company representatives
  • soil conservationists
  • state department of agriculture personnel

The 2014 Mid-Atlantic Crop Management School will offer CCA continuing education units (CEU’s) approved by the Certified Crop Adviser Program in the following categories:

  • Crop Management
  • Nutrient Management
  • Pest Management
  • Professional
  • Soil & Water Management Development

Total CEU’s earned will depend on course selection. This school also provides Pesticide Recertification Credits for DE, MD, NJ, PA, WV, and VA and continuing education for Nutrient Management Consultants in DE, MD, VA and WV.

 

 

 

Nematode Assay Changes Effective September 1, 2014

August 19, 2014 in Uncategorized

Please visit the UD Field Crops Disease Management blog to read about important changes to the UD Nematode Assay Service: http://extension.udel.edu/fieldcropdisease/2014/08/16/nematode-assay-changes-effective-as-of-september-1-2014/

2014 Small Grain Variety Trial Results Now Available

August 13, 2014 in Uncategorized

The University of Delaware’s 2014 Small Grain Variety Trial reports are now online: http://extension.udel.edu/ag/field-crop-resources/variety-trials-corn-hybrids-small-grains-soybeans/

Upcoming Event: Field Day: Diagnosing Soybean Production Issues

August 1, 2014 in Uncategorized

Tuesday, August 12, 2014
4:30 – 6:30 p.m.
University of Delaware
Research and Education Center (old office building)
16686 County Seat Hwy
Georgetown, DE

The United Soybean Board and Delaware Soybean Board are teaming up with the University of Delaware to sponsor the Soybean Diagnostic Day. The boards administer the soybean checkoff, which collects one half of one percent of the net market value of soybeans when they are sold at the first point of sale. The checkoff supports soybean research, marketing and education. Diagnostic Day is supported by USB’s Technology Transfer program.

Diagnostic Day is designed to help growers feel more comfortable diagnosing soybean production problems. The event will last about two hours and will consist of in-field, hands-on training to detect and identify pests and diseases of soybeans, and will end with a dinner courtesy of the soybean checkoff.

Pesticide and CCA recertification credits have been requested.

There is no cost to attend but please RSVP by August 5 to Karen Adams at (302) 856-7303 ext 540 or adams@udel.edu.

Upcoming Event: University of Delaware Irrigation Field Day

August 1, 2014 in Uncategorized

University of Delaware Irrigation Field Day

The University of Delaware College of Agriculture & Natural Resources and Delaware Cooperative Extension will hold an Irrigation Field Day on Wednesday, August 20, 2014 at 10 a.m. at the Warrington Irrigation Research Farm located on the corners of Route 5 and DE 290 Cool Spring Road/Hurdle Ditch Road, just 4 miles south of Harbeson, Del. (Signs will be posted.)

The program invites farmers, industry professionals and the general public to tour UD’s Warrington Irrigation Research Farm. UD personnel will be sharing their latest irrigation research findings

  • Irrigated Corn, Wheat, Full Season and Double Crop  Soybean Irrigation Research Plots
  • Experiences with Subsurface Drip Irrigation for Agronomic Crops (SDI)
  • Soil Moisture Monitoring as a Tool to Refine Irrigation Management
  • Variable Rate Center Pivot Irrigation (VRI)

For more information contact Karen Adams at 302-856-2585 ext.  540

Research Sponsored by DNREC, Delaware Soybean Board, MD Grain Producers, NRCS and Vincent Farms

The 2014 Delaware Wheat Variety Trial Disease Ratings Now Available

June 20, 2014 in Uncategorized

The 2014 Delaware Wheat Variety Trial Disease Ratings have been posted to the UD Field Crops Disease Management Blog by Nathan Kleczewski, Extension Plant Pathologist: https://extension.udel.edu/ag/files/2012/10/Wheat-Variety-Trial-Writeup-2014.pdf

Small Grains Twilight Meeting-New Castle County

May 27, 2014 in Uncategorized

Date: Wednesday, June 18, 2014
Time: 6:00 p.m.
Location: UD Cooperative Extension Research Demonstration Area: 3/4 mile east of Armstrong Corner on Marl Pit Road-Road 429, Middletown DE
Registration: Please call (302) 831-2506 or e-mail sharonlu@udel.edu to register, for additional information, or if you require special needs assistance.
Bring: A tailgate or a lawn chair.
Credits: DE Nutrient Management and Pesticide credits will be offered.

Join your fellow producers and the UD Extension team for a discussion of this year’s demonstration trials and current production issues. Other topics will include nutrient management, pest management and weed management. We will wrap up with the traditional ice cream treat.

The meeting is free and everyone interested in attending is welcome. If you have special needs in accessing this program, please call the office two weeks in advance.

Dan Severson, Extension Agent – Agriculture, New Castle County Cooperative Extension