November 2015
6th Texas Invasive Plant and Pest Conference

The 6th Texas Invasive Plant and Pest Conference has been scheduled for March 9-11, 2016, at Sam Houston State University in Huntsville, TX. Plans are still being made, and registration is not yet open. However, here are the details that have been worked out so far:

  • Deadline for abstracts: January 21, 2016
  • Early-bird registration: ends by February 24. $50 for students and $150 for non-students
  • Student travel grants: application due by February 5, 2016

As more details become available, they will be posted on the website and here in the iWire.


TIPPC_Conference2016_date 2

Update on Issues with Website and Reporting

Last month we reported glitches with reporting observations on the website and with the Android version of the TX Invasives phone app. We are pleased to tell you that the Android version of the app has been updated and appears to be uploading photos as it should.

In addition, if you had tried to upload pictures but were unsuccessful becuase of the glitch, we have updated the website so that you can now upload pictures for those observations. Log into your account and click on the "Replace Image" link (see illustratin at right) for each observation that needs a photo, and follow the instructions to upload your photos.

Also, please be sure your photos are no larger than 1 MB.

Thank you very much for your patience! website

replace image illustrtn

Invasive Spotlight:
Tropical Spiderwort
Commelina benghalensis)

Tropical spiderwort, native to Asia and Africa, is an invasive perennial plant that grows quickly to form dense, pure stands, outcompeting other plants, especially those that are low-growing. Also known as Benghal dayflower, it has been reported recently as a problem in cotton fields in Alabama. In pastures, it can become the dominant species. In rice and other lowland crop  it can withstand flooding and waterlogged conditions. It can also be found in cultivated lands, field borders, gardens, grasslands, roadsides, disturbed areas, and waste places. Because it can root from the nodes, light cultivation can break plants and spread them. One plant can produce as many as 1600 seeds.

As a monocot, the leaves of the tropical spiderwort have parallel veins and are lily-like. Unlike grasses, the leaves and stems are thicker and more succulent. The stems are sprawling and will creep along the ground. Leaf blades are alternate, and ovate to lanceolate, 1-3 in (2.5-7.5 cm) long, 0.5-1.5 in (1.3-3.8 cm) wide. Unlike other dayflowers (or spiderworts) the young leaves are hairy. The stems are sprawling.  

Unlike other spiderworts or dayflowers, tropical spiderwort produces both aerial and underground flowers. The aboveground flowers are very small with two relatively large lilac-to-purple/lavender (not blue) upper petals and a small whitish lower petal, and are present from the spring into the fall. Underground flowers, which grow on burrowing rhizomes, are white and very small.

Tropical spiderwort is found in 6 states, but has so far not found its way to Texas.  Because of its potential for ecological and agricultural harm, it is one of the “Dirty Dozen” pest species identified by the Texas Invasive Plant and Pest Council. It therefore is one of the “Report It!” alert species on the website and reporting app. It is also on the Federal Noxious Weed List.

If you believe you have found tropical spiderwort, please report this species.

Follow this link for more information on the tropical spiderwort.

 Tropical spiderwort flower

Photographer: Herb Pilcher
Source: USDA Agricultural Research Service,

tropical spiderwort undergroundflower

Underground flowers of tropical spiderwort, which look like swollen nodes.
Photographer: Byron Rhodes
Source: University of Georgia,

tropical spiderwort map

More News

Riparian and Stream Ecosystem Workshop Set for Dec. 3 in Nacogdoches
The Texas Riparian and Stream Ecosystem Education Program will host a workshop from 8 a.m.-4 p.m. Dec. 3 in Nacogdoches for area residents interested in land and water stewardship in the Attoyac Bayou watershed. The free workshop is co-hosted by the Texas A&M AgriLife Extension Service office in Nacogdoches County and the Attoyac Bayou Watershed Partnership. The morning session will be at the Courthouse Annex, 203 W. Main St. The afternoon session will include a walk and presentations along the bayou. For more information see this post.

Duck Season Reminder: Clean, Drain, Dry
Duck season is here and Texas Parks and Wildlife would like to remind all duck hunters to clean, drain and dry their equipment. Boats aren’t the only potential proverbial Trojan horse for zebra mussels (Dreissena polymorpha) and invasive aquatic plants; other gear like trailers, waders and decoys need to be cleaned as well. Read more about how to prevent the spread of aquatic invasive species at this site.

West Nile Had Bigger Impact on Bird Populations Than Previously Thought
A new study takes an in-depth look at the impact the West Nile virus has had on North American bird populations. This is the first look at the demographics of bird populations in the wake of the virus that first made news in 1999, and the results are not good. Large-scale population declines occurred in half of the species studied. Some groups like corvids were able to rebound, while others like the tufted titmouse are still suffering population declines. Read more about the study and how the West Nile virus is still affecting North American bird populations at

Rising CO₂ May Benefit Invasive Marine Species
A study recently published in Research and Reports in Biodiversity Studies by researchers from the University of Plymouth has shown that invasive aquatic species such as stinging jellyfish (Pelagia noctiluca) and Japanese kelp (Undaria pinnatifida) may benefit from ocean acidification. Rising CO₂ levels seem to both help and hinder the spread of marine invasive species as community dynamics are impacted, allowing Red King crabs (Paralithodes camtschaticus) to find new areas while endangering larvae. Learn more about the relationship between rising CO₂ levels and invasive marine species at

Mussels in Vegas
Lakes Mead and Mohave are infested with Quagga mussels (Dreissena bugensis). Brought to Lake Mead by a boater in 2007, the species has quickly become a problem. While scientists conduct dives to monitor the growth of the mussels, a researcher from the Desert Research Institute and his students are using a lab to find a way to combat the invasive species. Read more about the infestation and its potential impact on water supply here.

How Biological Communities Resist Invasion
Biotic resistance, or how well a biotic community can resist an invasion by a new species, is hypothesized to be determined by species richness. Species-rich communities can defend themselves from invasive species more effectively than species-poor communities. A researcher at Umeå University in Sweden studied past introductions of freshwater fish to Swedish lakes to test the role species richness plays in the establishment of new species. It was discovered that the complex relationships among species had more influence on biotic resistance than was previously thought. Learn more at

Citrus Greening Affects the Asian Citrus Psyllid
A study investigating the impact of the bacteria responsible for the deadly citrus greening disease, Candidatus Liberibacter asiaticus (CLas), on its host, the Asian citrus psyllid (Diaphorina citri), has yielded insight into the relationships of bacteria within the insect. CLas is not a harmless infection, as it causes a change in metabolism and subsequently may alter the feeding habits of the psyllid, which may in turn aid in the transmission of the disease. The study has created the opportunity for more research into the symbiotic relationships between bacteria and insects and how disease can affect them. Read more about the study and the search for pesticide-free disease control at

Interrupting the Vibrations of "Love"
As noted above, greening disease is a serious threat to the citrus industry. Spread by the Asian citrus psyllid (D. citri), the disease has cost the Florida citrus industry billions of dollars over the last decade. Researchers at the USDA and University of Florida are looking to stop the spread of the psyllid by disrupting their mating vibrations. The citrus psyllid uses wing vibrations to “call” out to potential mates and researchers can now mimic those vibrations. Learn more about this potentially pesticide-free way of slowing down the citrus psyllid at this Scientific American article.

Invasive Species Threatens Ireland’s Honeybees
The common rhododendron (Rhododendron ponticum) is considered one of the most invasive species in the United Kingdom. A threat to the forest habitats of Ireland, new research has shown that the nectar of the rhododendron is extremely toxic to native honeybees. Grayanotoxins, compounds found in the nectar, also impaired an Irish solitary bee species while having no apparent impact of bumblebee species. Read more about the study at

Cane Toads Aid Birds in Australia
The crimson finch (Neochmia phaeton), a bird from the Kimberley region of Northwest Australia, has found an unusual ally—the invasive cane toad (Rhinella marina). These toxic toads have caused a decline in the population sizes of three monitor lizard species. The decline of these near-apex predators and the subsequent increase in their prey populations, including the crimson finch, prompted research in prey and predator density dynamics. Learn more about the research at

Major Breakthrough in Search to Cure Chytrid Fungus
For the first time, researchers have successfully eliminated the chytrid fungus (Batrachochytrium dendrobatidis) from a wild population of mallorcan midwife toad (Alytes muletensis). The team of researchers treated the environment using a combination of antifungal treatments on mallorcan midwife toad tadpoles and a decontaminant commonly used to sterilize laboratories. The chytrid fungus has been a major factor in the decline of amphibians worldwide. Learn more about this new elimination method.

If you would like your invasive species event or news listed in the next iWire, please send the details to


Sentinel Pest Network and Invaders of Texas Species Workshops

Invaders of Texas workshops train volunteers to become citizen scientists to detect and report invasive species. Workshops, which are free, include information on the Sentinel Pest Network which serves to increase the awareness of early detection of Emerald Ash Borer, Cactus Moth, Asian Longhorned Beetle, and other pests of regulatory significance.

Workshops are tailored to meet the interests of your volunteer group, and supplementary session examples include an introduction to the TX Invaders mobile application and the Eradicator Calculator, a feature on designed to help organize and track volunteer-based eradication efforts.

Upcoming Workshops:

Saturday, December 12, 2015
Location: Edith L. Moore Nature Sanctuary (Houston, TX)
Contact: Bethany Foshée

For more information or to register to attend a free workshop, please visit the Workshop Page.