March 2021
What’s Inside My Moss Ball?

Zebra mussels (Dreissena polymorpha) have been found inside moss balls, an aquarium plant product sold at aquarium and pet supply stores. Moss ball are squishy balls of green algae, about 2 to 5 inches in diameter. In nature, they roll along the bottom of rivers, which gives them their round shape, and is likely how they picked up the zebra mussels.

What should you do if you recently purchased moss balls?

Destroy, Dispose, Drain!

Do not throw them away, or dump aquarium water without first properly treating the moss ball and the aquarium! Destroy the zebra mussel/moss balls in one of three ways: freeze, boil, bleach/vinegar. The aquarium the moss balls were in will also need to be cleaned, and the water will need to be treated. Please dispose of any moss ball packaging in a sealed plastic bag in the trash.

For more information and instruction on how to dispose and report moss balls with zebra mussels, please visit:

Please remember, zebra mussels are considered highly invasive throughout the U.S., and can quickly established and take over a water system. Accidental introduction through dumping can cause significant damage, such as disruption of the food chain, the clogging of pipes and water intake valves, and can cause changes in water chemistry. You may not see the zebra mussels in your moss balls. Zebra mussels can be very small.

Moss ball and Zebra mussel.
Moss ball and Zebra mussel. Credit: IDFW.


The Southern Coast is Going Tropical

A new U.S. Geological Survey-led study has found that tropical plants and animals are expanding their territory northward as the Southern coast becomes more tropical. According to the study, decreases in the frequency and intensity of extreme winter cold events are expected to allow an expansion of many cold‐sensitive tropical organisms. This will be seen in a pole-ward direction, and could push out temperate organisms. The study examines how the southern coast, from California to Florida, is experiencing winters that are growing shorter, and that the mean temperatures have risen since 1948. They also noticed there are fewer days where the mercury falls below zero.

Many species have a temperature tolerance and are thermoregulated to various habitats. Shorter winter freezes may allow tropical animals to expand their range and distribution because they are no longer limited. This includes the increased potential for the spread of nonnative and invasive grasses that fuel wildfires across California and other western states, mangroves (tropical salt-tolerant trees), snook (warm water coastal sport fish), and invasive species such as Burmese pythons, Cuban tree frogs, Brazilian pepper trees, buffelgrass, and others.

Some changes are already underway, while others are anticipated to occur in the home ranges of 22 plant and animal species from California to Florida. Cold-sensitive mangrove forests have been displacing temperate salt marsh plants along the Gulf and southern Atlantic coasts for 30 years. Due to sea-level rise, mangrove forests could also displace temperate and freshwater forests. Recreational and commercial fisheries are being disrupted by changing migration patterns and the northward movement of coastal fishes. Tropical mosquitos are likely to further expand their ranges northward, putting millions of people and wildlife species at risk of encephalitis, West Nile virus, and other vector diseases. The southern pine beetle is likely to move northward with warming winters. This beetle is a pest that can damage commercially valuable pine forests in the Southeast.

However, some cold-sensitive native plants and animals may expand their ranges as well. Researchers believe tropicalization along the southern coast will likely occur by the end of the century.

Read the research: Osland et al, 2021

Osland et al 2021 map
A map illustrating tropical‐temperate climate and ecological transition zones in North America. Credit: Osland et al. 2021

Osland et al 2021 poleward range expansion pathways
Four generalized depictions of alternative poleward range expansion pathways for tropical organisms in response to warming winters. Credit: Osland et al 2021

Invasive Weeds That May Help With Disease

Andropogon virginicus is a native bluestem grass in the southeastern U.S. It has since been introduced to California and Hawaii where it is considered a weed, and has become an invasive nuisance species in many other parts of the world. Andropogon virginicus competes with other species by releasing herbicidal allelochemicals from its dying tissues, seriously damaging agricultural production and economics in areas where it is invasive.

An international research team has found that A. virginicus extract has potential applications in future medical productions and therapeutics of chronic diseases such as type 2 diabetes and blood cancer. Researchers sampled the aerial parts of the invasive weed and found they are rich in flavonoids, palmitic acid, phytol, and γ-sitosterol. The finding suggests that A. virginicus is a promising source of the following agents: antioxidant, anti-diabetic, anti-tyrosinase, and antitumor. When tested at skin level, this helps prevent age spots by inhibiting a protein called tyrosinase. The extracted plant chemicals bind to free radicals that help prevent knock-on cellular actions that can lead to type 2 diabetes. The extracted chemicals also appeared to kill off cancer cells when directly applied to a line of chronic myelogenous leukemia. Researchers say further testing is needed to confirm and develop the natural functional products from A. virginicus for pharmaceutical and therapeutical purposes.

Read the research: Hoang Anh et al. 2020

Andropogon virginicus. not flowering
Andropogon virginicus. Not flowering. Credit: John Ruter, University of Georgia.
 Andropogon virginicus. aerial fruites 
Andropogon virginicus. Aerial fruites. Credit: Ken Chamberlain. The Ohio State University.

Trading Our Problems

Invasives are a problem. Anyone that reads this newsletter knows that. But what is the connection between exotic pets and invasive species? It seems like we don’t have to wait very long before we are reading another news article about exotic pets turning invasive or being captured in the wilds. An example occurred earlier this month, when a non-native Central American milk snake was found in the Mahogany Hammock Trail in Everglades National Park in Florida. Read more here. USGS believes it was a released pet, and was an isolated incident, but these events keep happening, and they don’t always have such happy endings.

A link has been found between invasive species and commercial success in global pet trade, according to a recently published paper by Gippet and Bertelsmeier, 2021. Using extensive meta-analysis, their findings suggest the global pet trade may be accelerating the spread of invasive species throughout the world. Researchers looked at mammals, birds, reptiles, amphibians, fish, and ants traded as pets. They found that invasive species seemed to be “overrepresented," indicating the greatest commercial success seemed to specifically favor invasives. This is likely due to their generalist habitat and care requirements, which is also what adds to the invasive species’ ability to be such a threat when introduced to a new habitat.

They found that approximately 12.6% of the pet trade is made up of invasive species. Invasive mammal species being sold in the pet trade were 7.4 times more frequent in the global pet trade than in the wild. Ants being sold in the pet trade were 6.6 times more common in the global trade than they were found in the wild, and were sold approximately 1.7 times as often than non-invasive ants. The meta-analyses suggests that buyers prefer invasive species, making them even more pervasive.

A large number of invasive species that are purchased either escape or are released by the people who buy them. Researchers ask for increased risk awareness regarding the international trade of wildlife species as pets due to the increased risk this can pose on biodiversity, agriculture, and health.

Lockwood et al 2019 image of exotic reptiles being sold at an expo
Example of exotic reptiles being sold at an expo. Credit: Lockwood et al 2019
Padilla and Williams 2004. alternative into of invasives in aquatin ecosystem
Comparison of alternative pathways for the introduction of fish in Florida and the US as a whole. Aquarium release is the largest source of introduced fish in Florida and the second largest source in the country. Credit: Padilla and Williams 2004

Emerald Ash Borer Vs. Fungus! Round 1!

The emerald ash borer (EAB, Agrilus planipennis) has killed millions of ash trees since its accidental introduction into Michigan in 2002. New research from the University of Minnesota's Minnesota Invasive Terrestrial Plants and Pests Center (MITPPC) identifies a number of fungi living in EAB-infested trees. The fungal communities associated with EAB galleries, and the role these fungi play in tree death is poorly understood. This research is the first step in identifying and understanding fungi that attacks the EAB, and paves the way for future testing of biological control agents.

The adult beetle is a bullet shaped (10-13 mm) beetle that bores a distinctive D-shaped hole in the ash trees upon emergence. The larvae (1.5 in) feed on the phloem and outer sapwood of ash trees, leaving S-shaped galleries that cut the circulation of phloem to the tree, resulting in tree death. The galleries can grow up to 20 inches long. The different fungi are introduced to the tree by spores entering through wounds in the bark. The fungi are often carried by the larvae as they develop, or as tunnel galleries are formed. The EAB galleries are providing a new niche space for fungal community formation.

The fungi were sampled along EAB galleries and identified through genomic DNA sequencing. The three fungal guilds identified comprised of canker pathogens, wood decay, and entomopathogenic fungi. Entomopathogenic fungi are pathogenic to insects, and have the greatest potential for biological control. Wood decay causes wood rot or decay in the wood, making phloem feeding difficult, but could cause hazardous tree conditions. Canker pathogens were found to have the potential to cause lesions that expand the necrotic area around EAB galleries. Although researchers found that some of the fungal growth could accelerate the decline of tree health, other fungi could provide options for biological control agents.

Read the research: Held et al. 2021

Dara et al 2019 Adult of Agrilus planipennis infected with Beauveria bassiana as a result of pre-emergence field cage trials. 2
Adult EAB infected with Beauveria bassiana as a result of pre-emergence field cage trials. Credit: Dara et al 2019.
Dara et al 2019 Entomopathogenic fungi on Agrilus planipennis
Examples of Entomopathogenic fungi on EAB. Credit: Dara et al 2019

EDD Maps Summit 2021

The EDD Maps Summit is a free Virtual Meeting featuring training, Q&A with developers, panel discussions, and more. This summit is suited for any EDDMapS user–from beginners to experts!

  • Day 1: March 31, 11am- 11:30am REGISTER. Building Capacity to Address the Invasive Species Threat.

  • Day 2: April 1, 11am- 2pm REGISTER.
    Full agenda details for day 2 can be found on

Using Genetic Engineering to Combat Invasive Species Webinar

The Aquatic Invasive Species Detectors Program at the University of Minnesota is offering a free webinar entitled “Using Genetic Engineering to Combat Invasive Species Webinar”

  • Thursday, April 29th, 1:00pm. REGISTER.

  • About the webinar: Recently developed tools for Precise Genome Engineering have ushered in a number of novel proof-of-concept technologies for pest control. Termed ‘genetic biocontrol’, these approaches allow researchers to essentially convert the pest organism into a pesticide. Released genetically engineered biocontrol agents would spread deleterious genes into the pest population, leading to a local eradication. This talk will introduce several types of genetic biocontrol, describe how they work, and give a status update on technology development efforts. A question-answer period will allow attendees to learn more about this promising and possibly transformative class of technologies.

U of Minnisota webinar

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:

  • April 21, 1pm- Emerald Ash Borer Deregulation and Programs Going Forward. REGISTER.
  • May 5, 1pm- PlayCleanGo Awareness Week and How to Integrate PlayCleanGo Outreach Tools. REGISTER.
NISAW Part II: Outreach and Education:
  • May 17, 1pm- The Climate Crisis and Invasive Species. REGISTER.
  • May 18, 1pm- The Model Legislative Framework for State Aquatic Nuisance Species (ANS) Programs and Resource Toolkit for Local Governments. REGISTER.
  • May 19, 1pm- The Regulatory Process for Classical Weed Biological Control. REGISTER.
  • May 20, 1pm- Aquatic Plant Management Priorities. REGISTER.
  • May 21, 1pm- A Comparison of State Noxious Weed Lists and an Overview of the Western Weed Action Plan. REGISTER.


Invasive Spotlight:
Asian Citrus Psyllid
(Diaphorina citri)

The Asian citrus psyllid (Diaphorina citri) are small brown insects that grow to about 1/8 inch (3mm). Adults are phloem feeding insects, usually feeding on the underside of leaves. They eat with their head agains the leaf and their body in the air, holding themselves at a 45 degree angle from the leaf. They can live up to 1-2 months. They have a temperature tolerance of below 68°F. The adult female abdomen turns bright yellow-orange when she becomes gravid (pregnant), and she lays bright yellow-orange, almond-shaped eggs on the tips of growing shoots. Nymphs are slow moving and generally yellow-orange in color, feeding exclusively on new growth. They produce waxy tubules as they feed that direct the honeydew away from their bodies. Nymphs have five nymph stages (instars) that look similar, increasing in size after each molt, with the later instars developing large wing pads. Development from egg to adult requires 16-17 days. The psyllid could complete up to 30 generations per year. Asian citrus psyllid populations decrease when citrus is not flushing because the immature stages require flushing plant material. In some places, like southern Florida, the psyllid is present all year round on orange jasmine (Murraya paniculata), a common ornamental shrub.

The host range of Asian citrus psyllid includes 25 genera in the family Rutaceae, the citrus family. The most common or preferred hosts are in the genera Citropsis (cherry oranges), Citrus (lemon, lime, orange, grapefruit, kumquats, etc.) and Murraya (curry, orange jasmine, and jessamine). The Asian citrus psyllid is a vector of the phloem-inhabiting bacteria Candidatus liberibacter asiaticus, which causes citrus greening disease (Huanglongbing). For more information on citrus greening disease (Huanglongbing) click here.

Almost the entire state of Florida has an established infection of Huanglongbing in citrus plants. As of 2017 in Texas, this disease has been detected in Aransas, Brooks, Calhoun, Cameron, Harris, Hidalgo, Fort Bend, Montgomery, Nueces, Starr, and Willacy Counties. Citrus trade in many areas of Texas has been restricted or quarantined due to the presence of this invasive pest. The Asian citrus psyllid is also present in California, Georgia, Louisiana, and South Carolina.

For more information and management regarding the Asian citrus psyllid, click here.

If you believe you have identified a suspected Asian citrus psyllid, please take a picture and REPORT IT! to

ACP many adults David Hall
Multiple adult Asian citrus psyllids(Diaphorina citri) feeding on leaf. Credit: David Hall, USDA Agricultural Research Service.
Adult ACP David Hall
Adult Asian citrus psyllid. Credit: David Hall, USDA Agricultural Research Service.
ACP nymphs David Hall USDA Agricultural Research Service
Five nymph stages of Asian citrus psyllids. Credit: David Hall, USDA Agricultural Research Service.


Zebra Mussel Watch

TPWD has detected invasive zebra mussels (Dreissena polymorpha) at Medina Lake, which has now been classified as a positive infestation. Lake Placid will be reclassified to infested. For a description of the classification system click here.

The detection in Medina Lake, located near Bandera, TX, marks the first introduction of invasive zebra mussels in the San Antonio River Basin. Thanks to the report submitted by a member of the public, authorities were alerted to the presence of zebra mussels. Bandera County River Authority & Groundwater District (BCRAGD) have conducted surveys in the area, but have only found (and removed) a few adult mussels. The lake will remain at a positive status until evidence of a reproducing population can be determined. Plankton sampling for zebra mussel larvae will take place in May/June when they begin spawning, and settlement monitoring and shoreline surveys will continue.

At Lake Placid, located near Seguin in the Guadalupe River Basin, Guadalupe-Blanco River Authority employees discovered a population of adult zebra mussels in the hydroelectric turbine near the bottom of the dam. Numerous mussels of different size classes were found, indicating the presence of an established, reproducing population. Due to the presence of an established and reproductive population, Lake Placid will be reclassified from positive to infested.

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

Even record freeze couldn't eradicate Central Texas' toughest invasive species, experts say
Not even a historic week of freezing temperatures and record-setting snowfall last month could elevate some of the toughest invasive species known to Central Texas.

A research group proposes six guidelines for managing the impacts of invasive species
A group of researchers aims at developing management tools, not to completely eradicate invasive species, but to optimize the control of invasive species in the medium to long term.

A bipartisan push could change state wildlife protection
A bill in Congress could direct nearly $1.4 billion annually to state and tribal wildlife agencies to protect the 1,600 species listed under the Endangered Species Act and the 12,000 additional species that have been identified as declining or rare currently threatened by climate change, habitat loss, pollution, invasive species and poaching.

Hunting contest eliminates 350 hogs in East Texas
Feral hogs (Sus scrofa) are an invasive species in the U.S., and there are approximately 3 million across most all of Texas. East Texas has an estimated 25-30 pigs per square mile. Wood County, TX, held their sixth annual hunting tournament to help control the population.

When 'eradicated' species bounce back with a vengeance
Some invasive species targeted for total eradication bounce back with a vengeance, like the invasive European green crabs (Carcinus maenas) from a California estuary. The crabs increased 30-fold after about 90 percent had been removed.

Fire away: Removing imported red fire ants could boost burrow ecosystems
The gopher tortoise (Gopherus polyphemus) is a keystone species of the southeastern United States that dig burrows extending more than 30 feet, and serves as a habitat for more than 350 other species. One of these is the red imported fire ant (Solenopsis invicta). Removing S. invicta could boost burrow ecosystems.

Weed invaders are getting faster
New experiments comparing populations from distant regions show a clear trend for already fast invasive plants and how they rapidly adapt even faster traits in their non-native regions.

Study offers insights into management of invasive paperbark trees
The paperbark tree (Melaleuca quinquenervia) has become a weedy invader to the fragile wetlands of the Everglades. Management is difficult because of the trees large seed banks.

Citizen scientists help expose presence of invasive Asian bamboo longhorn beetle in Europe
A research team in Europe finds that recent records of the invasive, non-native to the Old Continent species are mostly sourced from citizen scientists and online platforms, including those of the Asian bamboo longhorn beetle (Chlorophorus annularis).

Gene drives may help control invasive grey squirrel in the UK
Researchers believe existing gene drive technologies could be combined to help control the invasive grey squirrel (Sciurus carolinensis) population in the UK with little risk to other populations.


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

Citizen Scientists Spotlight

American Conservation Experience Out in Force

The American Conservation Experience (ACE) Gulf Coast chapter is based out of Corpus Christi, Tx, and is made up of a group of volunteer AmeriCorps members and a full behind the scenes team. According to Josh Kalman, Director of Gulf Coast ACE, the AmeriCorps are their boots on the ground when it comes to invasive species removal and conservation ecology work. ACE is able to operate 2-4 crews of volunteers at one time with their 14 members. Other chapters have as many as 12 crews. AmeriCorps members are trained to use equipment like brush cutters, chainsaws, and properly dispense herbicides according to the laws and appropriate protocol.

ACE works directly with different partners such as TPWD, US Fish and Wildlife, and the Nature Conservancy in South Texas. The volunteer task force may work on a priority area for a few days, or on and off for the whole year. Once the task force is dispatched, they will stay in the area, sometimes camping on site. Field work is hard work, and these volunteers show how dedicated they are by completing 450 to 900 hour crew terms while working on a project. Many of these will include 10 hour days and 40 hour weeks.

Some of their recent work includes Brazilian Pepper tree (Schinus terebinthifolia) removal on the spoil islands (small island between
Padre Island and mainland) of Laguna Madre, Padre Island National Sea Shore. In 2019, a crew of six, and in 2020, a crew of five camped and worked on the small 12-acre spoil island to remove the target invasive species. While they were there, they also worked to recreate a historical site. A team plans to return to the spoil islands in June to remove more Brazilian Pepper trees.

ACE currently has a team working on a 12 week project treating Tamarix athel (Tamarix aphylla) and Brazilian Pepper tree in several tracks in the Laguna Atascosa National Wildlife Refuge, Padre Island, TX. They will cut back the invasives with chainsaws, and use a drill and fill method on the Tamarix athel that allows for injection of herbicide directly into the tree. In the same Natural Wildlife Refuge, the task force team will be pulling salt cedar (Tamarix sps) from low lying wet land areas that have been specifically drained with a water exclusion device. Once the volunteer team has successfully removed and cut down the salt cedar, the wetland area will be flooded again, and the target species should be eliminated without the use of herbicide. In the Lower Rio Grand National Wildlife Refuge, in the La Sal Del Ray tract, a second AmeriCorps team is placing and pulling tree tubes that provide seedlings with the necessary protection to survive in the open plains area for the next 9 months-1 year. This team will also be participating in a Direct Seeding Component Project that will place seeds and soil that have all been locally sourced. A third crew with the Gulf Corp is currently helping with restorations at the Palo Alto Battlefield in Los Fresnos, TX, where they are applying chemical treatments to target invasives that are encroaching on the natural habitats of the coastal prairie.

ACE has many future projects planned for the rest of the year. If you are interested in becoming an AmeriCorps member, contact Caryn Garcia, the Member Support Coordinator:

Cops member clears path to center of tree
Corps member clears a path to the center of a Brazilian Pepper tree, where herbicide will be applied to the girdled sections of the basal area. Kleberg Tract-Nueces Co. Coastal Parks, Corpus Christi, TX. Credit: ACE.

Corps member treating salt cedar with cut stump approach
Corps member treating salt cedar with cut stump approach. Galveston Island State Park, Galveston, TX. Credit: ACE.


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:

Thursday, April 22, 2021 (10:30am-12:30pm)
Invaders of Texas Workshop: Invaders of Texas program training and How to report invasive species.
Piney Woods Lake, Texas Master Naturalist
Location: Virtual
Contact: Nelda Tuthill

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