Hessian fly infestations have been detected in North Texas from the Northeast corner near the Oklahoma State line, and westward to the Haskell/Knox County area.
Infestations vary widely, with some fields showing limited potential for damage, and others facing severe yield loss.
Todd Baughman, Extension agronomist at the Texas Extension and Research Center at Vernon, says damage was apparent in wheat plants that were severely lodged in the Haskell/Knox County area.
“Inspection of lodged wheat tillers showed Hessian fly puparia (often referred to as flaxseed because of their appearance) inside the stalk of the plant at the location of the lodging.
“Many producers may experience lodging in fields and suspect damage from freezing temperatures,” Baughman says.
“Weather records indicate temperatures did not get low enough to cause this type of damage. In fact, current inspection of wheat fields has not found any noticeable freeze damage in the Rolling Plains. Blank heads can be found in some fields, but in most cases they have been associated with wheat stem maggot or dryland foot/root rot.”
He says Hessian fly infestations likely will be associated with fields planted early.
“Some varieties show resistance to Hessian fly, but most, if not all, varieties planted in the Central and Northern Rolling Plains are susceptible to Hessian fly. Therefore, any variety may have a potential for infestation. The other reason for the infestations is likely due to weather conditions that supported the pest's survival.”
He says growers can scout for Hessian fly infestations by looking for the brown puparia or small white maggots behind leaf sheaths, at the base of individual tillers, and at the nodes on stems. Plants may be stunted or lodged.
“In the current infested field, the brown puparia could be found at the location of the broken stem approximately one-inch above the base of the plant. Inspection of tillers not lodged indicated pupae could be found one-inch above the base of these tillers,” Baughman says.
“Eventually these tillers will most likely lodge. In general, the field was stunted and had an overall unhealthy appearance.
“One key will be for producers to inspect both lodged and un-lodged tillers in several areas of the field to determine overall damage. This may or may not provide an accurate estimate of potential yield loss, since yield compensation of surviving tillers is unknown.”
Baughman says wheat farmers can do nothing to cure the current infestation. “Knowing that the problem exists can help plan for next year.”
Producers may try several production practices to reduce potential for infestation:
Controlling volunteer wheat plants (which is also beneficial for control of many other pest problems);
Burying infested crop residues to a depth of 4 to 6 inches;
Seed treatments (Gaucho or Cruiser) and crop rotation;
Resistant varieties (unfortunately, these are very limited at this time).
For additional information, see the publication: Hessian Fly in Texas Wheat under Hot Items at http://peanut.tamu.edu/todd.htm.
This publication includes photos to help identify Hessian fly and subsequent damage, information on its life cycle, and current management strategies.
If you have any additional questions or need help in identifying Hessian fly, contact Todd Baughman, Agronomist, Texas Cooperative Extension, phone 940/552-9941.