November 11, 2004 No. 31
We have been getting calls about sick wheat. But in many cases dry weather and freeze injury are more prevalent than anything else right now.
However, there have been some confirmed reports of Hessian fly in southwest and north central Kansas. Extent of the problem is still unknown. We have gotten several calls, but they may all represent reports from a few fields. The rains this summer plus considerable volunteer wheat are probably responsible for the presence of Hessian fly, plus we also saw some evidence of Hessian fly in southwest and central Kansas last spring. This year’s mild fall has probably also contributed to the problem.
For infested wheat we probably need to sit back and see what percentage of the plants or tillers make it through the winter. Tillers that are infested now will probably winter kill. Thus, if the stand is greatly reduced, problems should be obvious early next spring. There is really nothing one can do right now. No rescue treatments are available, plus larvae are or will be entering the flaxseed stage fairly soon, thus they would be highly resistant to any type of insecticide.
It might be wise to monitor any volunteer wheat that may be present in the area. Where high populations of Hessian fly are observed in volunteer wheat, probably the best thing to do would be to pasture it off and then make sure it is destroyed by early March. Again, the volunteer may die-off over the winter, so one might as well graze it off now and tear it up early in the spring before the next generation of fly emerges.
The best way of destroying Hessian fly-infested wheat is probably going to be through tillage. Burying the stubble keeps the flies from emerging in the spring.
The bigger concern may be what to do with planted wheat fields with a moderate fall infestation of Hessian fly. One would suppose that this will lead to an increased potential for problems next spring. However, we are not sure we have any data on what the percent of damage will be next spring based on a certain percentage of tillers infested with larvae this fall. As with most insect problems, what happens will probably greatly depend on the weather next spring. I would guess that if the wheat makes it through the winter, then it has a shot of producing grain next spring. However, if the weather is just right then we may see significant lodging from the Hessian fly in areas where the fly is abundant this fall.
More information on the Hessian fly can be found in the publication The Hessian Fly – MF1076 available on the www at: http://www.oznet.ksu.edu/library/ENTML2/MF1076.PDF and another good reference is the University of Nebraska Neb Guide, Hessian Fly on Wheat http://ianrpubs.unl.edu/Insects/g46.htm which has colored pictures of the different stages of the fly.
Phil Sloderbeck, Randy Higgins, and Jeff Whitworth
The following samples were submitted to the Insect Diagnostic Laboratory from October 29 through Nov. 10, 2004:
10-29-2004, Reno County: Flea Larvae in home.
11-1-2004, Shawnee County: Mealybugs on White Pine.
11-2-2004, Stafford County: Winged Termites from yard.
11-5-2004, Harvey County: Drain Flies in home.
11-5-2004, Sedgwick County: Tarnished Plant Bugs in home.
11-9-2004, Gove County: Pine Tip or Shoot Moth damage to
Ponderosa Pine.
11-9-2004, Clay County: Hackberry Psyllids in yard.
11-9-2004, Sedgwick County: Soldier Fly Larvae in yard.
11-10-2004, Riley County: Sac Spider in home.
If there are any questions regarding these samples or about the identification of any arthropod please contact the Insect Diagnostician at 785-532-4739 or at bbrown@oznet.ksu.edu .
Bobby Brown
Brand names appearing in this publication are for product identification purposes only. No endorsement is intended, nor is criticism implied of similar products not mentioned.
Sincerely,
Phil Sloderbeck
Randall A. Higgins
Kansas State University
Extension Specialist
Southwest Research and Extension Center
Entomology (Crops)
Garden City
Jeff Whitworth
Bobby Brown
Extension Specialist
Entomology Diagnostician
Entomology (Crops)