Nebraska: Wheat survey prompted by potential Wheat Stem Sawfly population increase | TSLN.com

Nebraska: Wheat survey prompted by potential Wheat Stem Sawfly population increase

Susan Harvey, Research Technician and Jeff Bradshaw, Extension Entomology Specialist, UNL Panhandle Research and Extension Center

Western Nebraska wheat growers are being asked to participate in a survey of wheat stem sawfly to be conducted this year by the entomology lab at the University of Nebraska Panhandle Research and Extension Center.

University researchers fear the sawfly could be more widespread than previously thought, and pose a major risk to the crop. Grower participation will be key to getting an accurate reading of the situation.

The wheat stem sawfly is an important pest in many areas of the northern Great Plains and has been known to infest wheat fields primarily in Scotts Bluff, Banner and Kimball counties. During the 2010 Wheat Disease Survey conducted by UNL faculty, the presence of wheat stem sawfly adults was easily observed throughout the Panhandle during late May and early June, indicating that this insect may be more prevalent and present a more serious risk than previously thought.

Certain tillage practices may provide a favorable environment for this insect and may be responsible for its expanding range.

The accompanying photos show how wheat stem sawflies develop in wheat plants and how they affect the plants.

The wheat stem sawfly overwinters as a mature larva in wheat stubble. After pupating, the adult emerges in May from the previous year’s wheat stubble.

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After emergence, adult females deposit a single egg per stem in developing wheat and the hatched larva will begin to feed within the stem. Although blackened areas can develop on the stem (where the heaviest feeding has taken place), the damage is most distinct at the end of the growing season after larvae have cut stems to form pupal chambers, resulting in lodged wheat.

In response to this increasing concern, the Entomology Lab at the Panhandle Research and Extension Center will be leading a survey in 2011 to document the prevalence and abundance of the wheat stem sawfly and its parasitoids.

With the assistance of crop specialists, extension educators, crop consultants, and agribusinesses, growers throughout the western half of the state will be invited to participate in the survey. These wheat fields will be sampled for insect damage and the presence of parasitoids, which can greatly impact sawfly populations.

This survey should prove interesting and beneficial to wheat producers in Western Nebraska.

Grower participation will be the key to an accurate and informative survey. Any grower who is interested in this project is asked to contact: Susan Harvey, Research Technician at the Panhandle Research and Extension Center at 308-632-1250.

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