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. I am
happy to report that we found no surviving
sugarcane aphids in the overwintering site today. 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. All green Johnson grass shoots, crowns, actively
growing leaves and stalks, plus most rhizomes were methodically checked above
ground and below for the aphid with no survivors found.
Near
and alongside the predator exclusion cage containing the artificially infested Johnson
grass utilized for the trial were placed two temperature sensors. 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 are:
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 hour 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).
This is not to
say that we will not see the sugarcane aphid in this area this season. They could very easily migrate in annually,
much like the fall armyworm or the sorghum midge, and are very likely to do so. For now, we can feel as reasonably certain as
one site can that this aphid did not overwinter on the High Plains.
Thanks to Dr. Pat Porter and Dr. Ed Bynum for all their assistance and expertise. Good Luck,
Blayne Reed
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