June 2021
Don’t Mind Me, I’m Just Hitching a Ride

There is now so much ocean plastic that it has become a route for invasive species. This phenomenon is called plastic rafting. Rafting or oceanic dispersal is a natural phenomenon where marine organisms attach themselves to marine litter and travel hundreds of kilometers. In cases such as these, the marine litter is usually seaweed, such as sargassum, that provides a home for reef fish, pipefishes, seahorses and more. Marine plastic as an ecosystem has been given the term “plastisphere”.

Debris from storms has been known to transport non-native species, like sea snails, sea anemones, and isopods, across the ocean to new shores in “mass rafting” events. An increase in waste being dumped at sea and abandoned fishing gear serve as a floating ecosystem for sea life and non-native species. Colonized floating garbage also enables biofouling: aquatic organisms attaching themselves in mass (such as zebra mussels). Plastic rafting transports invasive species from one shoreline to another. Introduced invasives can disrupt habitats, carry diseases, or strain ecosystems when introduced to a non-native area. Various types of insects, crabs, corals, barnacles, and ocean organisms have been transported via plastic rafting.

Multiple efforts or technologies have been proposed to help monitor the growing amount of ocean waste. The Integrated Marine Debris Observing System is a system that would combine satellite imagery, trawl surveys, observations from ships, and data submitted to various organizations to keep track of marine litter. The system has not been implemented yet. Another effort is called the Floating Ocean Ecosystems (FloatEco) multidisciplinary project to better understand the dynamics of floating plastics in the open ocean environment. Although monitoring is important, a combined effort to reduce plastic use or an awareness by the general public can cause a big impact.

Ocean debris floating off coast of Hawaii has become home to many fish and invertebrates.
Ocean debris floating off the coast of Hawaii has become home to many fish and invertebrates. Note the fishing net incrusted with coral and shells. Credit: Bryce Groark. Alamy.

Some of the debris washed out to sea by Japans 2011 tsunami.
Some of the debris washed out to sea by Japan's 2011 tsunami. Credit: Science History Images. Alamy.

I See You!

Burmese pythons (Python bivittatus) have been a problem in the Florida everglades for decades. A new study shows that infrared cameras could make it easier to spot these invasive pythons, leaving the snakes with nowhere to hide. The infrared sensors are small and low cost, especially when compared to the damaging cost the Burmese inflicts on the ecosystem. Burmese pythons can be up to 20 feet long and weigh as much as 200 pounds. Their natural camouflage causes them to blend with the natural foliage, making them hard to see with the human eye or a traditional visible-light camera.

The research reported that when using a near infrared camera, Burmese pythons could be detected up to 1.3 times farther away than traditional visible wavelength cameras. In a previous study, the authors measured the reflectivity spectra of Burmese pythons in the visible and infrared wavelengths, finding that pythons are more visible against the background at infrared wavelengths longer than 750 nm. Although they did not acquire the reflectivity of other snakes, they can distinguish Burmese pythons from others mainly by size differentiations. Contrary to other studies, this study does not rely on thermal contrast. They also determined that near infrared cameras could detect the pythons during the day and at night with illumination to improve detection. The researchers are currently trying to determine how to make this technique field ready in the Florida everglades as they are still in the beginning stages of the project.

Read the research: Hewitt et al. 2021

Burmese pythons image taken with NIR camera copy (top), traditional visible-light camera (bottom)
Burmese pythons (Python bivittatus) image taken with (a) near infrared camera camera, (b) traditional visible-light camera. Credit: Hewitt et al. 2021.

Controlling Criteria for Biocontrol’s

Researchers from Wageningen University have proposed a new series of methods for finding an effective biological control agent. This prosses can be daunting since pests can often have dozens to hundreds of natural enemies. Scientist must find one control agent that fits a lot of different criteria: one that will cause no ill effects on the plant or crop “under attack” or to the ecosystem, successfully eliminates the pest, is flexible in varying climates and areas of irrigation, etc.

The first step is evaluation criteria, or to evaluate all criteria to eliminate any clearly ineffective or “risky” species from the list of candidates. The second step is aggregate evaluation criterion, or to evaluate the pest kill rate to compare the pest population reduction capacity. The pest kill rate is the average daily lifetime killing of the pest by the natural enemy under consideration. While testing these methods, the research team was looking for a biological agent for the tomato leafminer (Tuta absoluta), a small moth whose adults and larvae damage tomato leaves and fruit. When using evaluation criteria, researchers were able to eliminate 180 of the 200 candidates for control of T. absoluta. After evaluating the pest kill rate, several natural enemies could be removed from the list of potential candidates, and a couple candidates showed real promise. Although there were criteria that the pest kill rate did not account for, such as natural damage the biocontrol may cause to the tomato plant as well as the pest, the findings showed that these methods could be used to rule out a large number of natural enemies and make the list of potential candidates more feasible to work with.

Read the research: Lenteren et al. 2021

tomato leafminer (Tuta absoluta).
Tomato leafminer larvae (Tuta absoluta) eating its way through a tomato. Credit: Marja van der Straten.
 tomato leafminer adult (Tuta absoluta). 
Tomato leafminer adult (Tuta absoluta). Credit: Marja van der Straten.

Something Fishy Next Door

What was once thought to be a single invasive species of cichlid intruding upon the water ways of southern U.S. has been confirmed by Louisiana researchers to be two different closely related species. The new species is the Rio Grande Cichlid (Herichthys cyanoguttatus), sometimes referred to as the Texas Cichlid. This fish is native to the Rio Grande and drainages of northern Mexico and southern Texas, but can now be found throughout Texas, Louisiana, and Florida. It is about the size of a human hand, with bright bluish-green spots over gray-green scales. Since this is a popular pet, it is believed to have originally escaped into the wild or have been dumped by their owners. The Rio Grande cichlid is aggressive and territorial, allowing it to dominate the ecosystems it enters. This causes many problems with the native fishes, especially bluegill.

The closely related fish that the Rio Grande cichlid was mistaken for is called the lowland cichlid (Herichthys carpintis). Since traditional morphology and genetic techniques where insufficient in differentiating the two species, researchers relied on electrical photo archives, such as the Cichlid Room Companion and iNaturalist, as well as live and museum specimens for comparison. After years of hard work, it was determined that there was a second closely related invasive cichlid species present in the southern U.S. waters. This newly discovered cichlid has joined an increasing list of invasive species threatening natural populations of plants and animals. Louisiana has made it illegal to own either fish, and requires anyone who catches one to kill it immediately.

To read more about the tale of these two Herichthys: Kakuturu et al. 2021

Rio Grande cichlid (Herichthys cyanoguttatus).
Rio Grande cichlid (Herichthys cyanoguttatus). Credit: USGS, U.S. Geological Survey.
lowland cichlid.
Lowland cichlid (Herichthys carpintis). Credit: H. Zell. CC By- SA 3.0

Are You Eating My Crops? 2 of 12

The maritime garden snail (Cernuella virgata) is a relatively small snail, and the second headliner in our new 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 invasives@shsu.edu

The maritime garden snails shell is globose-depressed and white or yellowish white in color with a prominent spotted spiral banding on the shell that is dark brown. The snails grow to be 6 to 19 mm high and 8 to 25 mm wide. Shell size and banding patterns can vary some. The maritime garden snail, like most other snails, are nocturnal and hide during the day. They are most active at night, in the mornings, or after the rain. During the summertime they can often be found in mass atop plants, feeding on new plant growth. They also aestivate (similar to hibernation) on plant heads and stalks. When they do this in large groups, it can contaminate crops and clog machinery. Attacked plants exhibit extensive rasping and defoliation. Like other mollusks, it can also be detected by signs of ribbon-like excrement and slime trails on plants and buildings.

The maritime garden snail closely resembles the white Italian snail (Theba pisana) in appearance and pest status. However, the white Italian snail has a more pronounced spiral banding. Also, the umbilicus (hole about which the shell spirals) appears as a circular hole rather than being partially obscured as in the white Italian snail. Texas is a “moderate” risk based on host availability for this snail. Various organizations and surveys are underway to monitor for the presence of this pest.

To read more about the maritime garden snail, see the USDA fact sheet.


Banding of C. virgata.
Banding of maritime garden snail (Cernuella virgata). Credit: Tenby Museum.

Cernuella virgata. Poggiani Luciano
Group of maritime garden snails aestivating on plant .Credit: Poggiani Luciano.

U.S. Geological Survey - 2021 Summer Student Seminar Series

The U.S. Geological Survey's Nonindigenous Aquatic Species Database presents a seminar series focused on providing undergraduate students and early career scientists insight into federal career options as well as how various federal agencies work on invasive species issues nationwide. Learn how various federal agencies contribute to the management and research of invasive species Hear what opportunities those agencies provide for students in the 2021 Summer Student Seminar Series.

For more information about the seminars and to register go to: https://forms.gle/vQKA4ivvaHs3d85M9. Scheduled speakers:

  • July 9 - Dr. Cindy Tam (U.S. Geological Survey)
  • July 14 - Dr. Doran Mason (National Oceanic and Atmospheric Administration/University of Florida)
  • July 16 - Jolene Trujillo (U.S. Bureau of Reclamation)
  • July 21 - Chelsea Bahaty (U.S. Army Corps of Engineers)
  • July 23 - Kaitlin Kovacs (U.S. Geological Survey)
  • July 28 - Yale Passamaneck (U.S. Bureau of Reclamation)
  • July 30 - Dr. Rochelle Sturtevant (National Oceanic and Atmospheric Administration)
  • August 4 - Mike Ielmini (U.S. Forest Service)
  • August 6 - Dr. Earl Campbell (U.S. Fish and Wildlife Service)
  • August 11 - Dr. Craig Martin (U.S. Fish and Wildlife Service)
  • August 13 - Katie O'Donnell (U.S. Geological Survey)
  • August 20 - Dr. Jacoby Carter (U.S. Geological Survey)


North American Invasive Species Management Association Training Webinars

The 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:

  • July 21, 1pm- Best Management Practices for Pesticide Applications. REGISTER.
  • August 18, 1pm- Racial Equity & Environmentalism. REGISTER.
  • September 15, 1pm- Flowering Rush Biology, Management, and Control.REGISTER.
  • October 20, 1pm- Forestry BMPs for Invasive Species. REGISTER.


The First Detector Entomology Training Project

This general entomology course is designed for Master Gardeners and homeowners. It provides a general overview of entomology and helps homeowners to: recognize the common arthropods (pests and non-pests), confirm the identification of pest problems, and recognize/report suspect unusual, exotic, or invasive species. Click here for more information or to begin the course. Supported by Bugwood Wiki and USDA.

DSC_0068 mantis KK
Praying mantis (Mantidae, Mantodea). Credit: Kylee N Kleiner, TRIES.

Invasive Spotlight:

Northern Snakehead
(Channa argus)

The northern snakehead (Channa argus) is a fish that looks very similar to the native bowfin. They both have a long cylindrical shape, long dorsal fin and rounded tail fin. However, the snakehead has a very long anal fin that starts halfway down the body, a pelvic fin that is located close to its head and enlarged scales on the head. Snakeheads also have a large mouth with several sharp, canine-like teeth on the lower jaw. The northern snakehead can reach a maximum length of over 80 cm (31.5 in.) and weight of 7 kg (15.4 lbs).

Northern snakeheads reach sexual maturity in 2 to 3 years, at which time females release 1,300 to 15,000 eggs per spawn (in the summer), which can occur 1 to 5 times per year. The adults build a floating nest for the eggs and aggressively protect their nests from predators, eliminating other fishes in the water or bite humans that threaten their nests.

The northern snakehead has lung-like organ, as well as gills, that requires them to breathe air. This allows them to survive in low oxygen rich waters, or survive outside of water for several days if kept moist, and can travel over land to invade new bodies of water. Some species of snakehead can even live for long periods of time burrowed in mud. Northern snakeheads are also low temperature tolerant, allowing it to survive in cold water that ranges from 0 to 30 degrees C, which means they can survive in most of North America’s waterways once they become established.

Northern snakeheads have been imported to North America for the aquarium trade and may be sold live in Asian-style fish markets. No snakeheads have been found in Texas waters to date, but the threat exists. Because of the damage that can occur when they are inadvertently released into lakes and streams, all species of snakeheads are prohibited in Texas. It is illegal in this state to release into public waters, import, sell, purchase, transport, propagate, or possess any living snakehead, except under special permits issued by TPWD. Dead snakeheads (intestines removed) may be legally imported and sold.

For more information about the northern snakehead, click here.

If you believe you have identified a suspected northern snakehead, please take a picture and REPORT IT! to invasives@shsu.edu.

Northern snakehead (Channa argus).
Illustration of a Northern snakehead (Channa argus). Credit: Susan Trammell.
northern snakehead. sharp canine like on lower jaw.
Open mouth of northern snakehead. Note the sharp canine-like teeth on lower jaw. Credit: USGS, US Geological Survey.


New: 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 you 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 invasives@shsu.edu 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 texasinvasives.org 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. Texasinvasives.org will contact the appropriate Texas institutions to remove the species for sale.

If you would like more information please email invasives@shsu.edu and mention you want to assist with our Aquarium Watch.

Field Crop Pest Survey

Texas Research Institute for Environmental Studies (TRIES) is looking for farmers with corn, rice, or small grain (wheat, oats, etc.) fields who would like to participate in a Field Crop Pest Survey. By participating, you would be allowing a TRIES field biologist to come place a non-invasive USDA trap at the edge of your field and check it every few weeks. The traps will be monitored for a variety of invasive crop pests. Your participation would be beneficial to yourself as well as the local farmers throughout your county. If you live in one of the following counties and are interested in participating, or you would like some more information, please contact invasives@shsu.edu. Limited participation slots available. Beyond that, some fees may apply.

Counties of interest: Johnson, Ellis, Navarro, McLennan, Limestone, Bell, Falls, Milam, Williamson, Fayette, Bastrop, Colorado, Wharton.

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.

bucket trap. Whitney Cranshaw. Colorado State
Example of a bucket trap. Credit: Whitney Cranshaw. Colorado State. 


Zebra Mussel Watch

TPWD has upgraded Lake Brownwood, Inks Lake, and Medina Lake in the Colorado and San Antonio River basin to ‘Infested”, as an established population of invasive zebra mussels (Dreissena polymorpha) have been detected in all three lakes. For more information, see the official press release here.

The department emphasized the importance of continued help from boaters, marina operators and others to Clean, Drain and Dry all boats and water craft equipment before moving them, and remain vigilant to stop the spread of aquatic hitchhikers.

mussel signal KK
Credit: Kylee N. Kleiner, TRIES.

More News

Scientists Recommend Proactive Response to Invasive Plants
To help invasive species managers focus to their efforts, a team from the University of Massachusetts suggests prioritizing potential invaders based on the threat they represent by using a widely accepted rating protocol. phys.org

Research Says AI Technology to Divert Invasive Species in Illinois River Akin to ‘Crime Scene Photos’
Researchers are testing a way to use facial recognition technology to selectively divert invasive Asian carp species in the Illinois River in an attempt to remove the invasives while allowing the native fishes to pass. cities929.com

Dead 'Murder Hornet' Near Seattle is 1st Found in US In 2021
Scientists have found a dead Asian giant hornet (Vespa mandarinia) north of Seattle, the first discovered in the country this year thanks to a report made by a concerned local. phys.org

TTU Researchers Test Canine Olfactory Abilities in Hunting Invasive Zebra Mussels In Texas
The Department of Animal & Food Sciences and the Department of Natural Resources Management at Texas Tech University are collaborating on a research project to evaluate the ability of novel detection technologies to locate, identify and prevent the spread of invasive mussels (Dreissenid Mussel) by comparing the olfactory abilities of a canine to that of environmental DNA. everythinglubbuck.com

Biologists Find Invasive Snails Using New DNA-Detection Technique
Researchers discovered the presence of the invasive New Zealand mud snail (Potamopyrgus antipodarum) in waters they were inhabiting by employing environmental DNA. This invasive snail is found throughout the continental U.S. phys.org

Feral Hog Bait Could Be Studied by Two Texas Agencies
Texas A&M AgriLife and the Texas Department of Agriculture (TDA) are collaborating on an experimental use program that will evaluate the efficacy of warfarin as a feral hog (Sus scrofa) control method. texasfarmbureau.org

Predicting the Spread of Invasive Carp Using River Water Flows
Researchers are developing a three-dimensional (3D) model to better predict how the variable dynamics of river water flows influence the spread of invasive carp throughout the U.S. and how the flows may affect or influence spawning or reproduction. phys.org

Study Confirms Invasive Lionfish Now Threaten Species Along Brazilian Coast
Four new records of lionfish off the coast of Brazil confirm the invasion of the predatory fish into the South Atlantic for the first time. Findings discuss how the lionfish may have arrived in the region, and how Brazil's diving and fishing communities can help manage the invasion. phys.org


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 iwire@texasinvasives.org.

Citizen Scientists Spotlight

Shout Out to Citizen Scientists Everywhere

Research by a team of Resources for the Future (RFF) found that approximately one-fourth of new pests in the U.S. are detected by members of the general public. RFF set up a new database by dividing eight years worth of detections into three groups: government agencies, local extension specialists and researchers, and members of the public. After analyzing the data, they found 32-56% of invasive pests were first detected by government agencies, 8-17% were detected by research or extension personnel, and 27-60% were detected by the public.

Early detection of an invasive pest presence is critical and government agents/researchers can’t be everywhere, so having the extra eyes of citizen scientist is extremely helpful. Catching an invasive pest before it is too widespread can save a lot of time and resources. Efforts to control invasive pests and cost of damages to the ecosystems and economies can equal upwards of $160 billion each year in the United States. However, with the contributions of the public that price can be reduced and potentially lead to early detection.

Citizen scientists are significantly valuable to the scientific community and deserve a general shout out and mid-year Thank you!

  Thank you copy KK
Credit: Kylee N. Kleiner, TRIES.



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, and teach identification of local invasive plants, and to 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:

July 19th: Introduction to Sentinel Pest Network and Reporting
6-7pm via Zoom
Lost Pines Master Naturalists
Contact: Kathy Cox

August 9th: Sentinel Pest Network and Reporting Workshop
10am-12pm (in-person)
Highland Lakes Master Gardeners
Location: AgriLife Extension Office, Burnet, TX
Contact: Anelicia Cheney-Campbell

August 14th: Invasive Species Identification and Reporting Workshop
8am-12pm** via Zoom
The Woodlands Township-Heartwood Invaders Chapter
Facebook Event: https://fb.me/e/7d2LPMeHR
Contact: Terrilyn McArthur
** the time is subject to change

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