White County
 Gardening
Podcast
May 20, 2010
Pecan Phylloxera
(2:33 minutes)
Audio/Video Script
Sherri Sanders
County Extension Agent - Agriculture
The pecan phylloxera is a small, aphid-like insect that is rarely seen, but
the galls it produces are prominent and easily noticed. Severe infestations
cause malformed, weakened shoots that finally die; such infestations can destroy
entire limbs. Hello this is Sherri Sanders, County Extension Agent - Agriculture
in White county.
The pecan phylloxera overwinters as eggs located inside the dead body of a
female adult, which is in protected places on the branches of pecan trees. Soon
after bud break, the eggs hatch and the young insects migrate to opening buds or
leaf tissue to feed on expanding new growth. The individuals that hatch from the
overwintering eggs are known as stem mothers. Feeding by the stem mothers
stimulates the development of galls, which enclose the stem mother in a few
days. Inside the gall, the stem mother matures, lays her eggs and dies. Eggs
laid by the stem mother hatch within the gall, and these nymphs feed within the
gall until they mature.
In early July, the galls split open and the mature nymphs emerge as winged,
asexual adults. These adults migrate to other trees or other parts of the same
tree and lay eggs that are of two sizes. The smaller eggs hatch into male
sexuals, and the larger eggs hatch into female sexuals. Male and female sexuals
do not feed; their sole purpose is to mate and produce the overwintering egg.
After mating, female sexuals seek out sheltered places on a tree, where they die
with a fertilized egg inside them, protected for the winter.
The adults and nymphs are small, one-eighth inch long, soft-bodied and
cream-colored. They resemble aphids without cornicles (the protruding tubes
located on the dorsal end of aphids). You'll need a hand lens to observe and
identify them.
Because the galls are seen easily, pecan phylloxera infestations often appear
worse than they are. Once the galls appear, it is too late to control pecan
phylloxera for the season. However, in most cases it is not necessary to be of
much concern, since they usually do not cause enough damage to pecan trees to
warrant an insecticide application. If you would like to apply an insecticide
try Bayer Advanced Tree and Shrub Insect Control for systemic control that
requires no spray application. Only the trees that were infested the previous
year will need treatment, not the entire orchard. Certain native trees and
grafted varieties within an orchard become more heavily infested than other
trees.
For more information, please contact your local Cooperative Extension
Service. This has been Sherri Sanders in Searcy.
Back to
Gardening Podcasts
|
