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Texas Insect and Disease
Pests and Invasive Species
Pruning Guidelines for Prevention of Oak Wilt in Texas
The Texas Plant Disease Diagnostic Lab - info and
AgriLife Extension Plant Pathology Factsheets and
What's bugging you? check out City Bugs from the
Pest and Disease Alerts - TX Department of Agriculture
August 2015: The Black Twig Borer Poses a Threat in East Texas Trees
The black twig borer, with the scientific name Xylosandrus compactus, is a tiny ambrosia beetle barely 1/16 inch long. It bores into the thin twigs of over 220 trees and shrubs, including southern magnolia, grape, sweetgum, pecan, dogwood, water oak, red maple, redbud, grape and many other plants. Seemingly healthy trees are attacked. The first evidence of an infestation is a condition known as “flagging,” where scattered twigs throughout the tree’s crown wilt and die (see link). Close examination of the dead twigs will reveal minute, circular holes (1/32 inch in diameter), usually on the underside of the dead twig. The adult beetles introduce a fungus which causes a black staining of the sapwood. Females begin laying eggs within the infested twig from spring through fall. The larvae or grubs hatching from the eggs feed on the white fungal “ambrosia” and also on the pith (center) of the twig. Pupation and mating of brood adults occurs within the infested twigs. The insects overwinter as adults, emerging through the entrance holes of the parent beetles and attacking trees most commonly in the spring when dogwoods bloom.
Click here for more information
April 2015 - Crape Myrtle Bark Scale
Dr. Mike Merchant, Professor and Extension Urban Entomologist with the Texas A&M AgriLife Extension Service in Dallas, is spearheading the detection and education work on a new insect pest that is spreading to crape myrtle trees throughout Texas.
This insect was first detected in 2004 in Dallas, but it wasn't until last year that this scale was positively identified as an exotic scale, Eriococcus lagerstroemiae. In 2014, Texas A&M AgriLife Extension published an article about this scale. And, most recently, they have worked with the Southern IPM Center to create an information clearinghouse and citizen science database for this pest at http://www.eddmaps.org/cmbs/.
Dr. Merchant is asking folks in Texas who think they have encountered this pest to report it. The Early Detection and Distribution Mapping (EDDMAPS) site makes this process fairly simple. A person can register on the site and click on the REPORT SIGHTINGS tab and report a new location for this pest. A report is verified by pictures, so folks are encouraged to take a digital picture of the suspect infested tree. The site allows the inputter to pinpoint down to the precise block or backyard where the infested tree is located.
Control information for this pest is available both on A&M AgriLife Extensions' Texas fact sheet and on their EDDMAPS site. They are also planning some research this summer to screen new treatments for this pest that do not involve neonicotinoid insecticides.
Pest Alert: Houston Area Date Palm Lethal Decline Quarantine
June 2014: Budworm on Cedar Trees in Central Texas
Click here for more information here
May 2014: Tent Caterpillars: Click here for more info
July 2012 - Another
Exotic - Citrus Root Weevil
This is another exotic invasive pest
insect. It has caused problems in citrus in the
Rio Grande Valley, but it has a rather extensive host
list (over 270 plant species from 59 families).
See the attached article for more details. Below
is a report from June 26, 2012 in Houston.
Citrus Root Weevil - Diaprepes
Glen Cove St., Houston, Harris
County, Texas, USA
June 26, 2012
On Tuesday night, 6/26/12, I found
another Citrus Root Weevil in Houston. After the first
one was found in Houston in 2009, I found one on my
street, Glen Cove. Since I had not seen any in over two
years, I had hoped that they had gone away.
This time I found the weevil on the corner of my house,
I assume it was attracted to the light there.
Joe Pase, Texas Forest Service, 936.639.8170
BEETLE --- MANIA
BIOLOGICAL CONTROL OF SALTCEDAR IN TEXAS
The saltcedar leaf beetle feeds only on saltcedar and athel. Athel is a closely related species that grows along the Rio Grande River in Texas. If saltcedar or athel trees are not present, the larvae starve to death. Saltcedar beetles were first established in Texas in 2004 at Big Spring, TX. Since then, there have been no reports of beetles or larvae feeding on any other plant. except saltcedar and its close relative athel (Tamarix aphylla).
To see the 2012 review click here
June 2012 - Outbreak
of borers on oaks
East Texas foresters are receiving
numerous calls about insects killing their oak trees.
I have also been getting calls and e-mails about this.
I am seeing a lot of activity from metallic or
flat-headed wood borers on recently dead and dying oak
trees (and other trees). These borers are
basically scavengers on dying and recently dead trees.
With large trees, the beetles may be only attacking
parts of the tree that are dying or recently dead.
These beetles initially infest the cambium and then bore
into the wood. In order for them to successfully
infest the cambium, the cambium cannot be healthy.
That is why treating for the beetles to prevent
additional attacks is “after the fact” and does little
if any good. The borers are there because the
trees have other problems and the other problems relate
back to lack of water. These borers are NOT
killing the trees.
The borers are the insect family
Buprestidae and the genus Chrysobothris. They have
a bronze metallic underside and the wings (elytra) on
top are a gray to black color. When they spread
their wings to fly, they reveal a bright metallic green
color on the top of their back (abdomen). The
drought of 2011 has caused tremendous problems for trees
and various fungi and insects are responding to the
drought-stressed trees. The metallic wood borers
you are seeing are a part of this complex of insects and
fungi. Chrysobothris is a large genus that
contains at least 134 species in North America.
Here is a link to information about
one of the common Chrysobothris species. It has a
large list of hosts including oaks, even though its
common name is flat-headed apple tree borer.
Below are two photos I took of
various Chrysobothris in the collection at the Forest
Health office in Lufkin.
In the photo above you can see the
bronze metalic color on the underside of the beetles,
their gray to black wing covers (elytr), and the exposed
green back (abdomen) of one of the beetles that lost its
elytra. These beetles came from an emerald ash
borer trap, but they are also common on dying oak trees.
In the above photo is Chrysobothris
shawnee. You can easily see the green color under
the wings as well as the gray to black color pattern on
the top of the wing covers (elytra).
I hope this information will be
H. A. (Joe) Pase III, CF
Regional Forest Health Coordinator
Texas Forest Service
June 2012 - Eastern Speckled Oak Gall
ball on the tree?
They are galls caused by a tiny wasp commonly called a
cynipid gall wasp. There are many species and most of
them make a distinct gall. These galls are probably
caused by Loxaulus maculipennis. They are
basically harmless to the tree. You can cut one in half
and find fibrous filaments extending from the outer
shell to the center core. Inside the center core will
be a tiny larva which will eventually pupate and emerge
as a tiny wasp. The wasps are seldom seen and they do
Here is a link for some information.
See page 102 and 103
April 2012 - Outbreak of Texas Leaf-Kaytdid
Bexar, Comal, Guadalupe and Medina Counties
January 2012 - first detection in
Texas of citrus greening, a destructive plant disease
that poses a threat to the state’s citrus industry. The
disease was discovered in a tree in a commercial orange
grove in San Juan.
Learn more here
Cankers Disease may threaten Texas Walnuts
Click on me for details
Another outbreak of
Giant Asian Dodder
Click on image for information
Chalcid Wasp on Afghan pines
Click on me for more information.
Soapberry Borer - Have you seen me?
Click on me for more information
Dutch Elm Disease in North Texas?
Invasives, here? In Texas?
be a citizen scientist and find invasives in your area?
Emerald Ash Borer Update
Not a pest but it is curious: Stemonitis splendens
(Joe Pase, TFS in Lufkin)
It's a slime mold