July 2021
Churning Out That Carbon

According to an international team of researchers, wild pigs (Sus scofa) are releasing around 4.9 million metric tons of carbon dioxide annually across the globe by uprooting carbon trapped in soil, the equivalent of 1.1 million cars. The team used predictive population modeling coupled with advanced mapping to pinpoint the climate damage wild pigs were causing across five continents. The researchers simulated carbon emissions from wild pig soil damage based on previous research from America, Europe, and China. They modeled the soil area disturbed from long-term soil damage across multiple climate conditions, vegetation types, and elevations.

As the wild pigs churn over the soil looking for food, carbon is released into the atmosphere. Since soil contains nearly three times as much carbon than in the atmosphere, even a small fraction of carbon emitted from soil has the potential to accelerate climate change. Multiply that by the 36,000 to 124,000 square kilometers being uprooted by the millions of invasive wild pigs and there is potential for a problem. This affects soil health, carbon emissions, biodiversity, and sustainable development in local ecosystems. The models indicate that if wild pigs continue to expand into areas with abundant soil carbon, there may be an even greater risk of greenhouse gas emissions in the future.

Read the research: O’Bryan et al. 2021

wild hogs. Dan Clark. USDI National Park Service
Wild pigs (Sus scofa). Credit: Dan Clark, USDI National Park Service.

wild pig damage. Karan A. Rawlins. University of Georgia
Wild pig damage. Credit: Karan A. Rawlins, University of Georgia.

Invasives on the Move

If there is one thing invasive species do best, it is spread. Invasive silver carp (Hypophthalmichthys molitrix), spotted lanternflies (Lycorma delicatula), and rusty crawfish (Orconectes rusticus) have been found in new areas this month.

Silver carp had been found in Choctaw Creek, a Texas tributary of the Red River. A local angler reported the fish, and provided two specimens to the TPWD and the U.S. Fish and Wildlife Service who confirmed them as silver carp. This is the first recorded report of this fish in Texas waters, although they have been found in areas of the Red River in Oklahoma. This filter feeder has the potential to be very problematic if established, as it will cause significant changes in the river ecosystem by competing with the other river filter feeders and larval sportfish. These fish can also be a hazard to boaters because they are known to jump up to 10 feet out of the water when startled, hitting boaters and boats.

The spotted lantern fly was found in Switzerland County, Indiana, for the first time. This is the farthest west that the insect has ever been found. A local Indiana homeowner contacted DNR’s Division of Entomology & Plant Pathology (DEPP) with a picture of a fourth instar, larvae stage, spotted lanternfly that they found outside their home. DEPP staff discovered an infestation in the woodlot in the area within 2 miles of the Ohio River. DEPP and the USDA are investigating to determine how large the infestation is, and where it may have come from. They are also working to limit the spread and eradicate the population. Many states are on high alert for this pest because of the extensive economic and environmental damage this pest leaves in its wake, especially in vineyards and orchards. Officials have noticed that the spotted lanternfly seems to favor an invasive plant called the tree-of-heaven. This plant is widespread throughout the U.S., including Texas. Authorities believe anywhere the invasive plant is present, there is a good chance the insect is soon to follow.

The rusty crawfish was found in McPherson State Fishing Lake, Kansas this month after the Kansas Department of Wildlife and Parks funded a university project that conducted a widespread sampling of freshwater crustaceans, and found the invasive crayfish. This is the first time it has ever been found in the state of Kansas. This crayfish is very aggressive, out competing and attacking the local competition and wading people. Authorities believe it was released into Kansas waters as fishing bait. They are currently working on many different capture methods and techniques in order to develop the best removal protocol for the problem at hand.

silver carp (Hypophthalmichthys molitrix). USGS
spotted lanternfly (Lycorma delicatula). Lawrence Barringer. Pennsylvania Department of Agriculturerusty crawfish. USGSTop) Silver carp (Hypophthalmichthys molitrix). Credit: USGS. Middle) Spotted lanternfly (Lycorma delicatula). Credit: Lawrence Barringer, Pennsylvania Department of Agriculture. Bottom) Rusty crawfish (Orconectes rusticus). Credit: USGS.

Bag Me Some of That Biofuel

Lake Victoria in one of the African Great Lakes. The shores of Lake Victoria are clogged with invasive water hyacinth (Eichhornia crassipes), an aquatic Sounth Amarican plant that is hurting Kenya’s freshwater fishing industry, the economy, and the people’s health. Water hyacinth clogs the surface of the water, resulting in oxygen depletion and contributing to the decline of fish stock. The decline in fish supply can be felt in the entire supply chain, from the fisherman to fishing supply sellers, fish markets, and restaurants. The thick matts make navigating the lake very difficult for boats, tangle fishing gear, and clog water treatment systems. The dense weeds also provide a perfect breeding ground for mosquitos and other disease carrying insects. People who live in close proximity of the shores clogged with water hyacinth report higher incidents of health problems, such as skin rash, cough, malaria, encephalitis, gastro-intestinal disorders, and bilharzia/schistosomiasis (an illness caused by parasitic worms). Some areas have attempted to manually remove the matts, but the process is slow and labor intensive, and the plant spreads quickly so manual removal does little in the way of alleviating the problem.

At Dunga Beach, Kenya, locals are finding innovative ways to turn this invasive plant into a reusable resource. The plant is made up of tough fibers and has been used to make chair seats, mats, and blankets. The plants are also being used as biofuel for economically vulnerable households to be used for cooking. The plant is turned into a slurry using a biodigester and used to fuel a biofuel stove, both of which are provided for them. The household also receives free maintenance on this equipment and regular refills of the crushed water hyacinth.

Elsewhere in Kenya, the prickly pear cactus (Opuntia stricta) is a massive problem, growing out of control, and out competing native grasses. About 10,000 acres have been occupied by the invasive plant. Local livestock owners lose many of their livestock to cactus related injuries every year when their cows and goats ingest thorns in an attempt to get to the fruit of the prickly pears. They also suffer an economic loss when they have to sell the livestock at a lower price since the intestines, a delicacy among the Maasai, cannot be eaten because of all the thorns that have become lodged in the digestive tract. Prickly pear cactuses are also being converted into biofuel. In a similar process as that of water hyacinth, the cactuses are harvested, turned into a slurry, and used as biogas in biofuel stoves for cooking.

crushing water hyacinth into pulp for biogas digesters. credit Anthony Langat.
Resident of Dunga Beach crushing water hyacinth into pulp for biogas digesters for local households. Credit: Anthony Langat.
 refilling biogas digester with prickly pear pulp. credit Anthony Langat. 
Kenya resident refilling biogas digester with prickly pear pulp. Credit: Anthony Langat.

biogas digester unit installed a a Dunga village household. used for cooking. credit Anthony Langat
Biogas digester unit installed in a Dunga village, Kenya, household. Used for cooking. Credit: Anthony Langat

Bacterial Transfer Causes Colony Mortality

European fire ants (Myrmica rubra) are named for their painful sting, but are only distantly related to fire ants in the genus Solenopsis. Nonetheless, populations of these invasive ants have been reported along the east coast of the U.S. and Canada. Myrmica rubra has a negative impact on biological communities through the suppression of native ant species, exacerbation of plant feeding homoptera (suborder of Hemeptera, plant feeding insects), and by lowering arthropod abundance and diversity. They are also a significant nuisance for home and business owners, as well as public land managers.

While surveying pathogens and parasitoids associated with M. rubra on Mount Desert Island and Orono in Maine, scientists found colonies of dead ants infected with entomopathogenic fungi and Pristionchus entomophagus nematodes. They collected live and moribund (at the point of death) ants from nests and dunghills and found the nematodes emerging from the dead ants. The researchers set out to determine if the nematodes contributed to the ant’s mortality by transporting the bacteria from the soil to the ants. They also attempted to determine what bacterial communities and fungi might be involved in the infestation.

Myrmca rubra workers exposed to P. entomophagus nematodes resulted in infection and death far greater than that of the controls when tested in laboratory settings. The nematode feeds on the host after they die of natural causes, and the juvenile Pristionchus spp. enters the insect host through a natural opening, such as the mouth or anus. Researchers found that the nematodes transported bacteria from the genus Serraia and Pseudomonas into the ants they infected and may be the cause of the ant’s mortality. Many different species of these bacteria are found naturally in the environment, and under the right conditions they can cause harm to insects, animals, or even humans. The researchers believe there is still a lot to learn about the relationship between bacteria-infected nematodes and mortality rates in M. rubra, but there is hope that research like this may provide information for potential biological control options in the future.

Read the research: Ishaq et al. 2021

European fire ants (Myrmica rubra)
European fire ants (Myrmica rubra). Credit: Eli Sarnat
graphic abstract from Ishaq et al 2021
Graphic abstract from Ishaq et al. 2021

Are You Eating My Crops? 3 of 12

The cucurbit beetle (Diabrotica speciosa) is an important pest throughout southern South America, and is the third 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 cucurbit beetle is grass green with three pairs of vertical yellow spots along the elytra and a set of red markings on the edges of the elytra like shoulder pads. The head is typically reddish brown to black with long filiform (threadlike) antenna almost as long as the body. The first three basal segments of the antenna are lighter than the rest, which are the same dark coloring as the head. The adults grow to between 5.5- 7.3 mm long. There are three larval instars (immature stages) which are differentiated by size. They are chalky white with dirty yellow to light brown heads, and the body is covered in long light brown setae (hairs). The third instar builds an oval cell in the soil in which they can pupate. The pupal form is long and white, about 5.7 to 7.1mm long.

The females can lay over 1000 eggs in their lifetime. The eggs are laid in the soil near the host plant. Maize, peanuts, and wheat are the preferred host plant of the cucurbit beetle. However, they are highly polyphagous and have been known to feed on the foliage, pollen, flowers, and fruit of many plants. These beetles can be detrimental to many different types of vegetation and crops. Feeding on young plants can cause a condition called “goose neck” where the plant experiences reduced vigor and grows bent due to reduced nutrient uptake. In some cases, this causes the plant to lie on the ground. The adults feed on the tassels, which prevents pollination and reduces kernel numbers in maize. The larvae are pests to the root systems of plants, which can cause stunted growth or plant death. In areas where the cucurbit beetle is present, there are years where the population is so heavy that vegetable crops are almost completely destroyed. Redistributing contaminated soil via farm equipment or through the sale of nursery plants is a concern as it can spread eggs and/or pupae unknowingly.

To read more about the cucurbit beetle, see USDA fact sheet.


Cucurbit beetle. credit Dirceu N. Gassen. modification of figure from Walsh et al 2020
Cucurbit beetle (Diabrotica speciosa). Credit: Dirceu N. Gassen. Modification of figure from Walsh et al. 2020. Biology and managment of pest Diabrotica species in South America. 

cucurbit beetle. Jonas Janner Hamann
Cucurbit beetle damage on leaf. Credit: Jonas Janner Hamann

Cucurbit beetle damage. jason brock. university of georgia
Cucurbit beetle damage, example of "goose neck". Credit: Jason Brock, University of Georgia.

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:

  • 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

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:

  • 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.
  • November 17, 1pm- USGS and USFWS collaborative project to conduct a national horizon scan for organisms in trade. 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. Click here for more information or to register.

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

Invasive Spotlight:

Redbay Ambrosia Beetle
(Xyleborus glabratus)

The redbay ambrosia beetle (RAB, Xyleborus glabratus) is a dark colored, 2 mm long bullet shaped beetle with small puncture-like dents covering the elytra. RAB can be identified with a characteristic snout representing modified mandibles for taking up nutrients. Positive identification of X. glabratus is almost impossible without the help of a professional, but the smooth upper surface and abrupt apical declivity may help distinguish this invasive beetle from other native species. RAB larvae are legless, white grubs with amber colored head capsules. These grubs are found feeding on infected trees beneath or on the surface of the bark.

The RAB is originally from India, Japan, Myanmar, and Taiwan, where it is a known vector of the vascular fungus called Raffaelea lauricola, which causes the host plant to wilt and die within a matter of weeks to months. The adult female has a special organ she uses to carry the fungus, which she inoculates into the tree. The larvae feed on the fungus and not the tree itself. This insect-disease complex is referred to as laurel wilt. Flight allows the beetle to transfer the fungus to new hosts rapidly.

In 2002, RAB was discovered near Port Wentworth, Georgia by chance in a survey trap. Within three years, the beetle spread through the southeast U.S., and was associated with the death of ambrosia and sassafras trees in Florida. Experts believe introduction of RAB was facilitated by solid wood packing materials such as crates or pallets. Trees in the family Lauraceae, including redbay, sassafras, pondspice, bay laurel, and avocado are susceptible. Found in AL, AR, FL, GA, LA, MS, NC, SC, and recently in Bowie, Cass, Hardin, Jasper, and Tyler Counties, TX.

Report observations of possible RAB, such as symptomatic host plants, using the “Report It!” function of www.texasinvasives.org and the Texas Invaders mobile app.

Learn more by reading the most current Laurel Wilt synopsis, or view the most recent map to see Laurel wilt’s history of spread. Click the following link to learn more about the redbay ambrosia beetle.

redbay ambrosia beetle (Xyleborus glabratus). Michael C. Thomas. Florida Department of Agriculture and Consumer Services
Redbay ambrosia beetle (Xyleborus glabratus). Credit: Michael C. Thomas, Florida Department of Agriculture and Consumer Services.
redbay ambrosia beetle damage. Florida Division of Plant Industry. Florida Department of Agriculture and Consumer Services
Redbay ambrosia beetle damage. Credit: Florida Division of Plant Industry, Florida Department of Agriculture and Consumer Services.

redbay ambrosia beetle galleries. James Johnson Georgia Forestry Commission
Redbay ambrosia beetle galleries. Credit: James Johnson, Georgia Forestry Commission.

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 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. 


More News

CBP Seizes Invasive, Meningitis-Spreading African Snails from Traveler at Houston Airport
Customs and Border Protection agents found 15 live snails, deemed one of the planet's most invasive species and capable of spreading meningitis, in the luggage of a traveler who had arrived in Houston. washingtonexaminer.com

Worries over racism, waterways inspire push to rename fish
The "Asian carp" label is commonly applied to four imported fish species that are wreaking havoc in the U.S. heartland, infesting numerous rivers and bearing down on the Great Lakes. The name may soon be changed. phys.org

Tagged Grass Carp Unknowingly Betray Their Species
Michigan State University researchers are working with state and federal fishery agencies to implant electronic transmitters in grass carp (Ctenopharyngodon idella) so their movement throughout Lake Erie can be tracked and monitored. phys.org

Hot Temperatures Accelerating the Spread of Invasive Species
Scientists say the extreme heat can accelerate the spread of invasive species by altering their life cycles and their ability to spread into new areas. wdio.com

Removal of Barred Owls Slows Decline of Iconic Spotted Owls in Pacific Northwest, Study Finds
Researchers found that the removal of invasive barred owls (Strix varia) arrested the population decline of the northern spotted owl (Strix occidentalis caurina), a native species threatened by invading barred owls and the loss of old-forest habitats. sciencedaily.com

Quarantine State: California Prohibits Introduction of Spotted Lanternfly
A state exterior quarantine has been declared by the California Dept. of Food and Agriculture to prohibit the introduction of the spotted lanternfly (Lycorma delicatula) into the state. growingproduce.com

Why An Invasive Caterpillar is Munching Its Way Through Tree Leaves In the Largest Outbreak in Decades
The past several weeks has seen the voracious gypsy moth (Lymantria dispar) eat its way through tree leaves across southern Ontario and Québec, and from Michigan to Vermont. phys.org

Notes from Central Taiwan: The Invasive Onslaught
Taiwan sits on the boundary between two major zoogeographical zones, the Indomalaya and the Palearctic, and is host to hundreds of native species with roots in both regions. Its native reptile and amphibian populations are under threat due to the introduction of invasive species. taipeitimes.com

Conservation Concern as Alien Aphid Detected on Kangaroo Island
An invasive species of aphid could put some threatened plant species on Kangaroo Island at risk as researchers confirm Australia's first sighting of Aphis lugentis on the Island's Dudley Peninsula. sciencedaily.com

DNA Data and Modeling Reveal Potential Spread of Invasive Species
Scientists at the University of Southampton have found that a marine invasive species, a sea squirt (Pyura praeputialis) that lives on rocky shores, could spread along 3,500 kilometers of South American coastline if climate change or human activities alter sea conditions. 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.

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.