Sugarcane Aphid Overwintering Site – Hale County, Texas
Today, Dr. Pat Porter, District 2 Entomologist, and I concluded the Sugarcane Aphid Overwintering Site Trial near Hale Center in Hale County (central Panhandle 30 miles north of Lubbock). I am happy to report that we found no surviving sugarcane aphids in the overwintering site today. All green Johnson grass shoots, crowns, actively growing leaves and stalks, plus most rhizomes were methodically checked above ground and below. The site had been successfully infested with sugarcane aphids from sorghum last fall with a thriving and established population of aphids confirmed to be healthy within the predator exclusion cage area before the local killing freeze date last November.
Two temperature sensors were placed near and alongside the predator exclusion cage containing the artificially infested Johnson grass utilized for the trial. One sensor was placed in the soil surface near the cage and the other at a depth of 4.5 inches alongside neighboring Johnson grass rhizomes.
The temperature recordings for this winter were:
4.5 inch depth: hours below 32 degrees = 8 (all on Dec. 31). Lowest temperature = 31.7 degrees.
Soil surface: hours below 32 degrees = 1151. Lowest recorded temperature = 8.5 degrees. There were 109 days between Nov. 5th (tent deployment) and today that had at least one hourly temperature reading at 32.0 degrees or below. The last freeze was March 27th at 5:00 am. The longest continual period at 32 degrees or below was 65 hours (Feb 26 – March 1). The next longest was 64 hours (Dec 29 – Jan 1).
For now we can feel as reasonably certain as one site lets us be that this aphid did not overwinter on the High Plains. Good Luck.
EA-IPM, Hale, Swisher, & Floyd
225 Broadway, Suite 6
Plainview, TX 79072