July 2020
Standardizing Invasive Species Terminology

In the latest issue of Journal of Extension, Dr. Basil V. Iannone III et al. from the University of Florida discuss the problems associated with the variety of terms used when people talk about invasive species. This is a good article to help clear up the confusion you may have. Here is their abstract:

"The excessive number of terms associated with invasive species, and their often incorrect usage, hinders stakeholder education about the threats of invasive species. Here we introduce seven terms (native, nonnative, introduced, established, invasive, nuisance, and range change) that are applicable across invasive taxa, understandable, typically interpreted correctly, and useful for describing most situations regarding invasive species. We also list six terms to avoid (native invasive, invasive exotic, invasive weed, alien, foreign, and nonindigenous) that create confusion via their misuse and misinterpretation. The terms we propose will increase understanding, thereby promoting behavior changes aimed at limiting the negative impacts of invasive species."

Invasives terms

The Origin of the Asian Longhorned Tick in the US

In 2017, the first established populations of Asian longhorned ticks (Haemaphysalis longicornis) were detected in the United States. Further research found the tick, which is native to East Asia, to be widespread in the eastern U.S. and that it has been present in New Jersey since at least 2013. Its presence is worrisome because in other countries it transmits serious illnesses to people and animals and can cause significant losses in the cattle industry. Interestingly, the tick exists in two forms: one with males and females, and the other with self-cloning females that lay eggs without needing to mate, a process called "parthenogenesis." Its ability to reproduce parthenogenically is another cause for concern, since this allows it to easily establish a fast-growing population.

But where did it come from? Recent research involving about 25 collaborators at 20 institutions studied the genetic differences among several populations to answer that question.

"Their findings indicate that at least three individual ticks, from self-cloning populations, were brought to the United States, which explains why all adult Asian longhorned ticks found in the U.S. so far have been female. Overall, U.S. ticks are more likely to have come from an East Asian country (or countries) than from Australia and New Zealand… [They also] found evidence that these ticks traveled within the United States on wildlife as well as through the transport of pets or livestock."

Learn more at sciencedaily.org.
Learn more about the Asian longhorned tick at CDC.gov.

Nymph and female. Credit: CDC.gov

Nymph and female, undersides. Credit: CDC.gov

Three life stages of the Asian longhorned tick sized relative to the head of an insect pin. Credit: Matt Bertone, North Carolina State Extension

Utah Wants Citizens to Eat as Many ‘Enormous’ Invasive Bullfrogs as Possible

The American bullfrog (Lithobates catesbeianus) is native to much of the Eastern U.S -- so, not Utah. There, the frog is an invasive that is causing the decline of native amphibian species. It literally eats whatever it can fit in its mouth, which can be quite large considering bullfrogs can grow to eight inches long and 1.5 pounds. They've become such a problem that the Utah Division of Wildlife Resources is encouraging people to eat them. In a twitter post, DWR said, "They're an invasive species so catch as many as you want, and they’re really tasty!" The post also provided a link to tips on how to catch and cook them.

Read more at kansas.com.

bullfrogs caught by Utah DWR
Credit: Utah DWR

Ignorant Pet Owners Allow Popular Turtle to Go Wild

Pet owners are a source of invasive animals when they release pets they no longer want. This is the likely route of introduction for, for example, the lionfish (Pterois volitans) in the Caribbean and Gulf of Mexico and the Burmese python (Python bivittatus) in Florida. It is also the source of red-eared sliders (Trachemys scripta elegans) found outside their native range in the Southeast and south-central United States and northern Mexico. Red-eared sliders can live to over 30 years, so it's not surprising that owners will tire of them and release them into local waterways. In fact, the turtle is considered one of the world’s 100 most invasive species by the International Union for the Conservation of Nature.

One of the states that has attempted to reduce the likelihood that red-eared sliders are released outside of their native range is Rhode Island. The species is still legal to buy in Rhode Island, but with restrictions. However, not everyone follows the restrictions. Clearly, public education is needed. Learn more at ecori.org.

red-eared slider
Credit: Greg Hume, CC BY-SA 3.0

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:

  • August 19 – How biocontrol agents are approved and how to access them for your invasive species management needs (go to NAISMA 2020 Webinar Schedule page to register.
  • September 16 – Leaps and Bounds – How to jump over the barriers to preventing the spread of invasive species – REGISTER


Invasive Spotlight:
Trifoliate (Hardy) Orange
Poncirus trifoliata

Trifoliate orange, also known as hardy orange, is a deciduous shrub or small tree that invades woodlands, forest edges, fence rows and urban green spaces. It can grow into large thickets, crowding out all other plants. Its large thorns make it especially problematic.

It grows from 8 to 30 ft. (2.4-9.1 m) high. The leaves are alternate, compound with three leaflets (trifoliate), up to 2 in. (5.1 cm) long and have a winged petiole. The twigs are green with stout, 1 in. (2.5 cm) or more long thorns. The bark is conspicuously green-striped. Spring flowers are white, 5-petaled, 1-2 in. (2.5-5.1 cm) in diameter and showy. Its fruit looks like a dull miniature orange, 1.5-2 in. (3.8-5.1 cm) in diameter, with a downy skin.

Hardy orange spreads mainly by dispersal of the fruit, which contain several seeds. Fruit can be carried downstream, where they come to rest in bottomlands; the several seeds then sprout, creating a new population.

Trifoliate orange was introduced from northern China as an ornamental due to its unique form and green color, beauty when flowering, and interest provided when fruiting. It was likely also planted as impenetrable hedges. Due to its hardy nature it is often used as rootstock for citrus trees.

Trifoliate orange needs to be watched closely since it can easily become established and create even more competition for desirable trees in forest settings. To prevent the spread of trifoliate orange, do not plant it; choose alternative plants, and eradicate the plants you find outside of a landscaped setting. Control can be achieved by hand pulling seedlings or, for larger specimens, the cut-stump application of an herbicide. Contact your local Texas A&M Forest Service or AgriLife office for specific recommendation and as always follow label directions. To be safe use basic precautions like gardening gloves, long pants & long sleeved shirts, and eye protection.

In Texas this invasive plant is found in mainly in the eastern woods.  It is found throughout the sourthern United States and up into Pennsylvania. 

(Some information for this article comes from this link)

Follow this link for more information on hardy orange.


Photographer: John D. Boyd
Source: Mississippi State University, Bugwood.org


Credit: Diann Mabus, citizen scientist, Invaders of Texas

under trifoliate orange

Infestation in Big Thicket National Preserve.  Note there is nothing growing under the thicket.
Credit: Hans Landel, Lady Bird Johnson Wildflower Center


By the Numbers
  • 20: Number of mussel infested boats that inspectors with Montana Fish, Wildlife and Parks have stopped at check stations since mid-March -- a record. This compares with just 16 mussel-carrying boats that were found during the entire 2019 season. Learn more.
  • 55: Number of boaters that received citations due to quagga mussel (Dreissena rostriformis or D. bugensis) concerns over the Fourth of July holiday weekend across Utah, according to Utah state conservation officers. An additional 322 vessels were decontaminated. Learn more.

More News

Portable DNA Device Can Detect Tree Pests in Under Two Hours
A new rapid DNA detection method can identify forest pests and pathogens like Asian gypsy moths (Lymantria dispar asiatica) and white pine blister rust (Cronartium ribicola) in less than two hours, without using complicated processes or chemicals -- a substantial time savings compared to the several days it currently takes to send samples to a lab for testing. Learn more at sciencedaily.com.

Asian Longhorned Beetle Declared Eradicated in Two Canadian Cities
This was the only known population of ALHB (Anoplophora glabripennis) in Canada. ALHB is a highly destructive wood-boring pest of maples and other hardwood trees including poplar, birch and willow. It has the potential to devastate Canada's hardwood and maple syrup industries. Learn more about this victory at newswire.ca.

Burmese Pythons Spreading “Tongue Worm” to Native Snakes
It’s not enough that Burmese pythons (Python bivittatus) are choking down Florida fauna wholesale, now they’re spreading a harmful parasite to native snakes that could travel far afield of the invasive constrictor’s southern stronghold. Learn more at palmbeachpost.com.

A Big Rat in Congress Helped California Farmers in Their War Against Invasive Species
A taxidermied "swamp rat" convinced the House to unanimously pass a bill that supports eradication efforts in states infested with nutria (Myocastor coypus), large rodents also known as swamp rats that are native to South America. The nutria is one of several problematic non-native species in California discussed in this article: learn more at insideclimatenews.org.

Algae Species Discovered Infesting NW Hawaiian Waters Has Been Identified
A newly-identified, fast-growing species of algae poses a major threat to coral reefs and the ocean ecosystem in the northwestern Hawaiian Islands. Learn more at sciencedaily.org.

Invasive Hedgehogs and Ferrets Habituate to and Categorize Smells
A new study examines how invasive mammalian predators both habituate to and generalize avian prey cues. Learn more at sciencedaily.com.

Burrowing Crabs Reshaping Salt Marshes, with Climate Change to Blame
Given higher sea levels and softer soil in the wake of a shifting climate, Sesarma reticulatum crabs, which have already decimated salt marshes in the Northeast, are now rising to prominence in southeastern marshes, a new study finds. Learn more at sciencedaily.com.

Climate Change Is Impacting the Spread of Invasive Animal Species
What factors influence the spread of invasive animal species in our oceans? The Asian shore crab (Hemigrapsus sanguineus) is an example of invasive species successfully spreading to the North Sea and Baltic. Read more at sciencedaily.com.

Caribbean Wrestles with Mischievous Invaders: Monkeys
Likely first brought to the islands from West Africa as exotic pets by European settlers in the 17th century, today the monkeys (Chlorocebus sabaeus) are putting pressure on native species, decimating crops and consistently evading efforts to scare them off. Read more at unenvironment.org.

COVID-19 Restrictions May Aid B.C.’S Ongoing Battle Against Invasive Mussels
Travel restrictions linked to the COVID-19 pandemic might help British Columbia defend against invasive mussels, but the province is taking no chances as it works to keep the creatures out of B.C. waterways. Learn more at haidagwaiiobserver.com.

Invasive Crabs Threaten Fish and Fish Habitat on West Coast of Vancouver Island
The European Green Crab (Carcinus maenas) first appeared in western North America in San Francisco in 1989 thanks to shipping. Ten years later they were spotted around southern Vancouver Island and are now threatening fish and fish habitat as far north as the central coast of British Columbia. Learn more at cheknews.ca.

Exotic Insect Species Increase on The Azores Through Human Impact
A new study reveals that the diversity of exotic species of insects, spiders and other arthropods in the Azores is increasing, a pattern that has also been observed in other islands around the world. The study also found a slight decrease in the abundance of endemic species. Read more at sciencedaily.com.


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, 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:

Saturday, August 15, 2020
Sentinel Pest Network Workshop
Location: Virtual
Contact: Teri MacArthur

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