September 2021
Injurious Species Act Excels

The list of injurious wildlife regulates species expected to cause harm if they were to become established in the U.S. outside their natural range. Once a species is added to the list of injurious wildlife, it becomes illegal to import it into or throughout the continental U.S., the District of Columbia, Hawaii, Puerto Rico, or any U.S. territory without a permit (injurious wildlife provisions of the Lacey Act ). By prohibiting the importation of potentially destructive species, the spread of invasive species can be prevented before they enter the environment. Zebra mussels (Dreissena polymorpha), Burmese pythons (Python bivittatus), and some invasive carp are well-known examples of injurious species. However, these species are an exception to the rule, as they were added to the list after they had already become established, and causing harm in the U.S. Ninety-four percent of injurious species are listed preemptively, often limiting or eliminating the damage caused by that invasive species. Since 1952, 288 species have been identified as a potential threat and listed as an injurious species before they arrived in the U.S., and a total of 307 species are listed for invasiveness. A recent study found that in the case of preemptive listings, injurious species regulations were 100% effective at keeping injurious species out of the ecosystems (all 288 remained not established). The way the study measured success was by examining whether or not the species was established at the time of listing, if it has since been established, and if it subsequently spread to other states.

Indian flying foxes (Pteropus giganteus giganteus). charles j. sharp CC BY-SA 4.0
Indian flying foxes (Pteropus giganteus giganteus). Credit: Charles J. Sharp, CC BY-SA 4.0. Flying foxes or fruit bats of the genus Pteropus are injurious species and are listed under the Lacey Act.

Tumbleweed Decor

The United States Department of Agriculture classified tumbleweeds as a non-native and invasive plant throughout the United States. A tumbleweed is the mature structural part of many different species of plants that once dry, detaches from its roots and stems and rolls due to the force of the wind. In most cases, the purpose of this is to spread its seeds or spores as it bounces and rolls along the landscape. Tumbleweeds, such as Russian thistles (Salaola tragus), are considered noxious and detrimental to the environment. They are flammable and known to spread wildfires, bouncing over the land, and causing firebreaks. They are tied to wind erosion in open areas, as they are known to remove large quantities of water from the soil. They have also been known to cause roadblocks, and cover houses and cars.

But now people are finding alternative uses for these invasive spiky bouncing balls in an effort to clear out the roads and yards that are overrun with them. Tumbleweeds are being turned into chandeliers and sold as home décor on Etsy. Others are shipping them off to be used as props for movies. Who would have thought?

tumbleweed chandelierTumbleweed chandelier

Why So Crabby?

It is assumed that a successful population contains high genetic diversity and a variety of inheritable characteristics that allow them to adapt and thrive in one’s environment. However, it turns out many invasive species, like the European green crab (Carcinus maenas), have a low genetic diversity, but still maintain the ability to spread rapidly and adapt quickly in new environments.

A recent study investigated the adaptive mechanisms of the green crab along the North American west coast where it has widely dispersed over the last few decades despite minimal genetic diversity or individual-to-individual differences in DNA/inherited traits. In order for a population to adapt to changes in the environment, variations within genetic diversity are often required, however invasive species seem to challenge this view. In the last 35 years, the green crab has spread from a single source and now spanning multiple environmental locations from California to British Columbia, over 900 miles. Researches found the population has lost a large amount of overall genetic diversity compared to its European counterpart. They also found that cold tolerance seems to be strongly selected for across all sample sites from north to south across the invasive West Coast range. It is believed this is an example of balanced polymorphism that evolved to promote adaptation to variable environments despite high gene flow and low genetic diversity. This is likely contributing to successful invasion and spread in novel environments. Researchers have also found successful populations of green crabs that have passed through a severe bottleneck event, suggesting that there is diversity in specific parts of the genome rather than having genome-wide diversity. This could play a critical role in resilience to new or changing environments in a population with an overall low genetic diversity.

Read the research: Tepolt et al., 2021

european green crab
European green crab (Carcinus maenas). Credit: Schofield, P. J., & Brown, M. E. (2016). Invasive species: ocean ecosystem case studies for earth systems and environmental sciences. Earth Systems and Environmental Sciences.
 map of sample site. green crab 
Map of European green crab sample sites and years of sampling. Credit: Tepolt et al., 2021

Oh Lady, Dear Lady

Long term research at the Kellogg Biological Station agricultural Long-Term Ecological Research site, Michigan State University, observed how the introduction of invasive lady bird beetles has caused changes in the native and exotic predatory communities.

Invasive species have the potential to reshape interactions within an entire community and influence ecosystems. This research examines 30 years of observations in which multiple invasions were detected, providing a wide range of impacts on both natural and managed ecosystems. The first invasive lady beetle detected was the European seven-spotted lady beetle (Coccinella septempuncata) in 1989, which comprised of nearly 80% of the total lady beetles captured. Since then, three additional exotic species have been observed: multicolored Asian lady beetle (Harmonia axyridis) in 1993, the variegated lady beetle (Hippodamia variegata) in 1997, and the fourteen-spotted lady beetle (Propylea quatuordecimpuncata) in 2006. The European seven-spotted lady beetle and the variegated lady beetle rapidly increased in abundance and became the dominant lady beetles in the community. At the beginning of the study there was a large number of native lady beetle species. However, now there is only one native species present, the pink lady beetle (Coleomegilla maculata), whose abundance reaches approximately 25% of the community. The abundance of the pink lady beetle is due to its diet of maize, an incomplete dietary niche overlap which allows it to survive despite the exotic lady bird species.

The researchers believe that the lower diversity lady beetle communities dominated by invasives may have been less resilient to disturbance or more susceptible to pathogens. Continued studies will determine if, and by what mechanisms, native lady beetles may be able to persist in the increasingly invasive-dominant insect ecosystem.

To read more about the research: Bahlai et al., 2021

bahlai et al 2021
Number of lady beetles in the KBS LTER community and soybean aphid outbreak years (top) and longterm trends in native vs. exotic lady beetle abundance (bottom). Credit: Modified from Bahlai et al., 2013

pink lady beetle. david cappaert
Pink lady beetle (Coleomegilla maculata). Credit: David Cappaert. Single native species left in sample community.


Are You Eating My Crops? 5 of 12

The old world bollworm (Helicoverpa armigera) is a major insect pest of both field and horticulture crops in many parts of the world, and is the fifth headliner in our 12-month series called ‘Are you eating my crops?’. Individual pests chosen for this series have not yet been reported in Texas, but are on the ‘Watch List’ due to their high level of pest importance or risk due to host availability. During this series we will cover several different crop pests, what to look for, what they look like, and where you can find more information about them. If you ever have question or concerns regarding the headliners of this section, feel free to email

The Helicoverpa armigera has been reported to cause serious losses throughout its range (Asia, Europe, Africa, South America, Australia) to tomatoes, corn, and cotton. It has also been known to cause damage to chickpea, peanut, pigeon pea, sorghum plants, and many other high value crops. The larvae prefer to feed on the reproductive parts of the host (flower and fruit) resulting in bore holes and feeding within the plant. Because of this, it is often necessary to cut open the plant to detect infestation. Larvae may also feed on the foliage. Secondary bacterial or fungal pathogens may develop due to the wounds on the plant. The old world bollworm has received pest status due to its broad host range, feeding preferences for reproductive stages of plants, its high mobility, high fecundity, and its ability to adapt to different climates.

The old world bollworm moth is 14 to 19 mm long as an adult with coloration that varies. Males are usually yellowish-brown, light yellow, or light brown, and females are orange-brown. The forewings have a black or dark brown kidney-shaped marking near the center, and the hind wings are creamy white with a dark brown or gray band on the outer margin. The pupae are dark tan to brown, 14 to 22 mm long by 4.5 to 6.4 mm wide, and are typically found in the soil. The larvae stage is made up of six instar stages, where the coloration of the caterpillar darkens with each molt and dietary content, ranging from blue green to brownish red. Freshly emerged larvae are translucent and yellowish-white with some dark-brown coloring near the front and end of the body. Larvae have a spotted appearance. Second instar are yellowish-green with black thoracic legs. Five prolegs are present on at all larvae instar stages. The eggs are yellowish-white when first laid, and change to a dark brown. They are gumdrop shaped, 0.4-0.6 mm in diameter, with longitudinal ribs and a smooth top. The eggs change to a dark gray to gray black the day before they hatch.

Helicoverpa armigera adults are easily confused with many other species of moth. Final identification requires dissection and examination of the genitalia by a seasoned researcher. If you believe you have identified a H. armigera infestation or have collected a specimen, please take a picture and send it to, where further specimen shipping information will be provided.

To read more about the old world bollworm, see the USDA fact sheet.

Helicoverpa armigera. Julieta Brambila. USDA APHIS PPQ
Old world bollworm, adult (Helicoverpa armigera). Credit: Julieta Brambila. USDA APHIS PPQ
old world bollworm. central science laboratory harpenden. larvae in tomato
Old world bollworm larvae, representation of damage to tomato. Credit: Central Science Laboratory, Harpenden.

old world bollworm. antoine guyonnet
Old world bollworm larvae eating the developing grain inside a corn cob. Credit: Antoine Guyonnet

Land Stewardship Series Focuses on Wildlife Management

The Texas A&M AgriLife Natural Resources Institute (NRI), in collaboration with the Noble Foundation and East Foundation, released the wildlife management collection focuses on ways landowners and outdoor enthusiasts can improve habitat for desirable wildlife species and minimize competition from invasive species.

Web modules with videos, audio recordings, photos, links to AgriLife publications and interactive quizzes guide users through lessons meant to enhance their knowledge and provide usable methods and ideas.

Controlling wild hogs and promoting habitat for quail are a major focus of the collection.

To view the entire collection, click HERE. More information on the NRI’s Private Land Stewardship Program and Private Land Stewardship Academies is available HERE.


22nd Texas Master Naturalist Program Annual Meeting

An event to gather, learn and celebrate another year of the Texas Master Naturalist Program. We’re preparing this year’s meeting as a HYBRID Event – both online and in-person at the Dallas/Fort Worth Airport Marriott in Irving, Texas. The event will be held the weekend of Thursday, October 21st through Sunday the 24th, 2021 with plenty of activities throughout the event! Join us for a long weekend of greenspace adventures in the hideaways of our largest urban area in Texas.

Click HERE for more information! or to register.

**Ashley Morgan-Olvera, with TexasInvasives and TISI, will be presenting on October 22 at 4:15PM with a presentation entitled “Stop the Spread!”, a discussion regarding invasive species of concern, invasives management resources & reporting database, Early Detection Initiatives at TISI, and how to schedule Citizen Scientist workshops.

master naturalist

North American Invasive Species Management Association Training Webinars

This program is designed to provide the education needed for professionals and students who are managing or learning to manage invasive species. The courses include the most current invasive species identification, control and management techniques, and how to comply with local and federal regulations.

Participants may register and enroll at any time, and will receive a certificate of invasive species management from NAISMA upon completion of the program.

All live webinars are open to the public. Recorded webinars are available to members of NAISMA.

NAISMA 2020 Webinar Schedule:

  • October 20, 1pm- Forestry BMPs for Invasive Species. REGISTER.
  • November 17, 1pm- USGS and USFWS collaborative project to conduct a national horizon scan for organisms in trade. REGISTER.
  • December 15, 1pm- Classical Biological Control of Weeds- About misconceptions and untapped opportunities. REGISTER.


2021 Invasive Species Research Conference – Turning Science into Action

The 2021 Invasive Species Research Conference will take place virtually in an online event portal. Learn about current and published research from over 40 presenters in a variety of themed sessions. The event will also facilitate connections between invasive species researchers and practitioners in the Pacific Northwest.

October 5-7, 2021

Click here for more information or to register.

untitled I_KNK3546
Unidentified hemipteran nymph. Credit: Kylee N Kleiner, TRIES.

Invasive Spotlight:

Cuban Tree Frog
(Osteopilus septentrionalis)

The invasive Cuban tree frog (Osteopilus septentrionalis) is the largest tree frog in North America, with adults ranging from 1.5 to 5 inches in body length, and females sometimes growing upwards of 6 inches. This is much larger than any native Texas tree frog. It has bumpy skin on the back, similar to that of a toad, and the skin on top of head is fused to its skull. This fusion is a key distinguishing characteristic and can often determine the difference between a Cuban tree frog and a similar looking native. A second key identifying characteristic is its enormous adhesive toe pads which are much larger and wider than its toes (as large as its eardrum) and are larger than the toe pads of native tree frogs in Texas. There are two Texas native tree frog species that are often mistaken for the Cuban tree frog, the Mexican tree frog (Smilisca baudinii) and the Gray tree frog (Dryophytes versicolor); however, both of these species are smaller in size, have smaller toe pads, and do not have the skin on the top of the head fused to the skull.

Cuban tree frogs can be highly variable in color, ranging from gray, gray-green, tan-brown, cream colored or yellow, or pale green without any markings to dark green or brown with an even darker color pattern on the back and legs. Sometimes they almost look white when they are inactive or cold. Individuals are able to color change rapidly. Small, juvenile Cuban tree frogs typically have greenish bodies with light side stripes, red eyes, and blue bones that are visible through the skin on the underside of the legs.

The breeding season lasts from May to October. This species prefers habitat that is moist and shady, such as in trees, shrubs or around houses. It is commonly found near ornamental ponds and well-lit patios. The voice, or call, of the Cuban tree frog is variably pitched, slightly rasping or like grating stone. The breeding event usually lasts only one night. Eggs are deposited as thin floating sheets into still water that lacks predatory fish. Tadpole’s hatch 2 days later. They metamorphose into froglets 3-8 weeks later.  Adult males typically live 2 months, but females can live for up to 2 years.

The Cuban tree frog causes ecological problems as a predator of a wide range of native frogs, toads, and lizards, in addition to insects and spiders. This species was introduced to southern Florida from the Caribbean and has continued to spread. There is a breeding population in New Orleans, and they have been found in Texas! It is very important that those of you in the Houston area and along the coast from the Texas-Louisiana border to past Galveston keep an eye and ear out for these frogs.

Wear gloves or put your hand in a plastic bag when handling the Cuban tree frog. They secrete a slimy film to protect their skin, which can irritate the skin and eyes of some people.

If you think you found a Cuban tree frog, please collect it if possible (using gloves) and REPORT IT! to Please include a photo, a description, and the location.

For more information review the following informative links: HERE is a flyer from Louisiana describing the Cuban treefrog, Informative web page from Louisiana HERE, information page.

cuban tree frog. Joseph Scopino 2
Cuban tree frog (Osteopilus septentrionalis). Credit: Joseph Scopino. Note the large toe pads.

CTF by Leanna Powers
Coban tree frog. Credit: Leanna Powers. Note the variation in color and pattern compared to the first image.

treefrog toepads cuban vs native. Monica E. McGarrity. TPWD
Treefrog toe pad illustration depicting cuban vs. native species. Credit: Monica E. McGarrity, TPWD.


Opportunities To Get Involved
Looking for participants for the following surveys: 

Citrus Greening Workshops

We need your help to safeguard Texas Citrus, and it can start in your backyard!

TISI is offering educational workshops focused on the Asian citrus psyllid and the pathogen Citrus Greening. The Asian citrus psyllid and the Citrus Greening pathogen is threatening citrus in multiple Texas counties, and we need your help to monitor the spread. The workshop will highlight what you need to look out for, address USDA-APHIS Citrus Quarantines, and offer diagnostic services if you suspect your backyard citrus has either the psyllid pest or Citrus Greening pathogen. This includes providing trapping materials, assisting with management strategies, and more.>

Please contact so we can schedule a workshop (virtual or in-person) for you or your group this year!

Aquarium Watch: Looking for Prohibited Invasive Aquatic Species

Please help and natural habitats by looking for 14 prohibited invasive aquatic species being sold in your local aquarium store. With just one photo you can assist us in finding and documenting which stores are selling prohibited species. will contact the appropriate Texas institutions to remove the species for sale.

If you would like more information please email, and mention you want to assist with our Aquarium Watch.

Air Potato Survey

Help Texas Research Institute for Environmental Studies conduct an air potato survey by actively reporting any infestations seen in your area. The air potato (Dioscorea bulbifera) is a fast growing, high climbing vine. Potato-like tubers are the primary means of reproduction for this vine. They can be as small as a marble or as large as a softball. Native yams are often confused for air potatoes, to avoid this confusion please refer to the key below:

- Plants rhizomatous; bulbils never produced in leaf axils; petiole base never clasping the stem; Native D. villosa
- Plants tuberous; bulbils produced in leaf axils; petiole base sometimes clasping the stem; Invasive D. bulbifera

For additional information, please refer to the TexasInvasives information page.

If you believe you have identified an air potato vine, please email and include the following information: an image, an approximate number of vines present, the location (including whether it is on public or private land), if bulbils are present (the potato-like tubers that emerge from the stem).



Citrus greening. JM Bove

Leaf mottle on grapefruit, a characteristic symptom caused by citrus greening bacterium but also seen on trees infected by Spiroplasma citri. Credit: J.M. Bove.

Armorded catfish. Photographer United States Geological Survey
Armored catfish (Hypostomus plecostomus). Credit: United States Geological Survey.

air-potato (Dioscorea bulbifera)2 bulbil. credit Karen Brown
Air-potato (Dioscorea bulbifera), bulbil emerging from leaf axil. Credit: Karen Brown.

More News

DFW Intercepts Frog That’s Deemed an Invasive Species
The Department of Land and Natural Resources’ Division of Fish and Wildlife recently intercepted a coqui frog (Eleutherodactylus coqui) from a Micronesia Air Cargo Services plane. 

US Asian Giant Hornet Nest Destroyed in Washington State
Officials in Washington state destroyed the first Asian giant hornet (Vespa mandarinia) nest of the season, located near the town of Blaine along the Canadian border.

One Water Bucket to Find Them All: Detecting Fish, Mammals, And Birds from a Single Sample
Environmental DNA (eDNA) is increasingly used to detect fishes in biodiversity monitoring campaigns. However, eDNA turns out to be capable of providing much more than fish occurrence data. This study demonstrates how comprehensively vertebrate diversity can be assessed at no additional costs.

Crayfish Get More Interesting at Bigger Parties, Study Suggests
In many North American lakes, the invasive rusty crayfish (Orconectes rusticus) roams lakebeds, snapping up snails, bivalves, and water plants, cutting off food supplies for native crayfish and other animals. They even raid fish eggs, which reduce the sports fishing populations.

Conesus Lake Watershed Council Battling Outbreak of Invasive Algae
An invasive species of algae known as Starry stonewort (Nitelopsis Obtusa) was found within the lake at Consesus State Park, Livonia, NY.

How Do Wild Pigs Affect Riparian Systems?
In the U.S., wild pigs (Sus scrofa) are an invasive species that can cause a lot of damage to the ecosystem where they live. Researchers write about how wild pigs can hurt riparian areas.

Non-Native Fish Are Main Consumers of Salmon in Reservoirs
New research found warmwater fish species like bass, walleye and crappie that are not native to the Pacific Northwest, that overlap with baby spring chinook salmon in reservoirs in Oregon's Willamette River, consume more baby salmon than native fish.

By reducing forest floor temperature, invasive shrubs stifle native species
Invasive shrubs in Northeastern forests that sprout leaves earlier in the spring and keep them longer in the fall absorb more sunlight than native shrubs, and their foliage lowers air temperatures on the forest floor, likely giving them another competitive advantage.

Invasive Fish Push Westward as the Mediterranean Sea Slowly Becomes Tropical
A host of fish species are swimming westward via the Suez Canal as the waters warm and become saltier turning from temperate to tropical. These new invaders may have perilous consequences for ecosystems.

Soil Legacy Effect of Global Change Influences Invasiveness of Alien Plants
Global change characterized by land use change and extreme precipitation has emerged as a challenge for tropical forests. A recent study examines the soil legacy effect of extreme precipitation and land use change on the absolute and relative biomass production of invasive plants.


If you would like to highlight a successful invasive species project or nominate a special person to be highlighted in an upcoming iWire, please send the details to

Sentinel Pest Network and Invaders of Texas Workshops

Invaders of Texas workshops train volunteers to detect and report invasive species as citizen scientists. Workshops, which are free, are designed to introduce participants to invasive species and the problems they cause, cover aspects of invasive species management, teach identification of local invasive plants, and train participants to report invasive plants using the TX Invaders mobile application. The workshop is 7 hours long (usually on a Saturday, but scheduling is arranged with each individual host group). The workshop satisfies Master Naturalist training requirements.

Sentinel Pest Network workshops serve to increase the awareness and early detection of a set of particularly important invasive species to help prevent their spread into Texas or their further spread within Texas. Participants learn to identify species such as the Emerald Ash Borer, Cactus Moth, Asian Longhorned Beetle, and other pests of regulatory significance, and to report them. The workshop is 3.5 hours long. The workshop satisfies Master Naturalist training requirements.

Upcoming Workshops:


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