November 2021
Maybe They Aren’t So Bad

Wasps don’t necessarily have the best reputation because of their ability to sting repeatedly and their perceived aggressive behavior, but if you look at them in a different light, they aren’t all bad. Many parasitic wasps are used as biological controls against invasive species which allow us to avoid or limit the use of insecticide, pesticides, and herbicides. Parasitic wasps sting to inject their eggs into a host, sometimes accompanied by venom or a virus. Their larvae then grows and eventually emerges from the host, usually killing it. The following are just two examples of parasitic wasps making waves in the biocontrol industry.

The cassava plant is a drought resistant staple food crop in Western and Central Africa. In the 1970’s, the cassava mealybug (Phenacoccus manihoti) entered the region and began devastating cassava fields, threatening the food base of hundreds of millions of people. Some areas saw crop losses as high as 80%. While conducting research, a Swiss entomologist found a parasitic wasp, called Apoanagyrus lopezi, parasitizing the cassava mealybug. Apoanagyrus lopezi was reared, and cocoons were air dropped from planes into areas affected by the mealybug. The parasitic wasp population grew and spread on its own, and the mealybug population gradually declined to more manageable levels.

Spotted-wing drosophila (Drosophila suzukii) cause damage to many crops, such as sweet cherries, berries, and stone fruit, by infesting fruit during its early ripening stages rather than when it is rotting, like other Drosophila members do. The females lay their eggs inside the fruit, then the larvae hatch and grow inside the fruit, often remaining inside to pupate. Researchers recently found a parasitic wasp, called Ganaspis brasiliensis, that parasitizes spotted-wing drosophila. This parasitic wasp is very host specific, ignoring other species, as it lays its eggs in the spotted-wing drosophila larvae. This specificity makes it an important biocontrol candidate which would be great for the fruit industry.


Anagyrus lopezi. G.Goergen. IITA 2Apoanagyrus lopezi , parasite of the cassava mealybug (Phenacoccus manihoti). Credit: G. Goergen, IITA.

Ganaspis brasiliensis. Kent Daane. UC RiversideGanaspis brasiliensis, parasite of the spotted-wing drosophila (Drosophila suzukii). Credit: Kent Daane, UC Riverside.


Invasive Species in Space?

We have protocols in place to reduce the probability of non-native species from crossing borders, but what about actual ‘alien’ species coming to Earth? We don’t often think about the possibility of accidental contamination of another planet with foreign species, or alien species being introduced to Earth. Although the likelihood of either of these events happening is low, many believe that biosecurity needs to expand and adapt, especially as space exploration expands. The government is not the only player in town anymore. With the arrival of private parties and new international players, space is now accessible to a broader range of individuals, making biosecurity more important than ever. There are some protocols already in place that prevent biological contamination of extraterrestrial environments from Earth and vice versa. NASA, the Committee on Space Research, and Article IX of the Outer Space Treaty of 1967, discuss different methods of planetary protection. For example, interplanetary rovers and other equipment are decontaminated and sterilized before launch, but even their clean rooms aren’t free of microbial life. For example, in 2019, the Beresheet spacecraft, carrying thousands of dormant tardigrades hitchhikers, crash landed on the moon. Although the tardigrades are likely in a nearly dead-like state, it is possible for them to be resurrected by being reintroduced to water.

A recent publication, Ricciardi et al., 2021, focuses on how planetary protection protocols should be influenced by current research on biological invasion protocols that we use on Earth based on human-assisted spread of organisms into novel environments, or ‘invasion science’. Protocols for early detection, hazard assessment, rapid response, and containment procedures currently employed for invasive species on Earth could be adapted for dealing with potential extraterrestrial contaminants on spacecraft or biological material transported to Earth for analysis. Although the contamination risks are currently mostly hypothetical, the 2019 lunar crash illustrated that there is a real risk, and therefore the need for disaster preparedness against ‘biological spills’. The collaboration between researchers in invasive science and astrobiologists is the next logical step, according to the research.

clean room. ricciardi et al 2021JAXA clean room. After the completion of the setup of the clean booth, a test run is underway for Hayabusa2 prior to launch. Credit: Ricciardi et al., 2021.

Hemiptera-Ant Mutualism and Invasive Relationships

Native and invasive ants can form mutualistic relationships with hemipteran insects (commonly called true bugs), prey on non-hemipteran herbivores, and indirectly affect primary production. Mutualism can enable the establishment and spread of invasive species and cause community-wide effects. Scientists looked at how the exclusion of native or invasive ants would affect the insect-plant food web. They did this by measuring the corresponding effects on hemipteran abundance, herbivore abundance, and plant fitness.

Results revealed that the exclusion of ants, whether native or invasive, significantly reduced hemipteran abundance, indicating a mutualistic relationship between ants and hemipterans. Excluding invasive ants had a greater negative impact on hemipteran abundance than native ants. This supports the "mutualism intensity" hypothesis, that the exclusion of both native and invasive ants had significant effects on hemipteran abundance. Native ant predation significantly reduced herbivore abundance, but exclusion of invasive ants had no effect. A high abundance of invasive ant-hemipteran mutualists reduced herbivore abundance, but the negative effects of the high density of herbivorous hemipterans on host plants may overwhelm the beneficial effects of reduced non-hemipteran herbivores. The exclusion of native ants significantly reduced plant fitness, but there was no significant impact of invasive ants on plant fitness. These results suggest a weak relationship between the presence of invasive ants and non-hemipteran herbivore abundance. The effects of ants on parasitoids and predators were not significant. Researchers suggest that hemipteran-ant mutualism could represent a ‘symbiotic invasion’, where the ecological dominance of invasive ants is facilitated by hemipterans.

To learn more about native and invasive relationships, read the research: Wang et al., 2021

ant-hemiptera mutualism
Mutualism between red imported fire ants (Solenopsis invicta) and cotton aphids (Aphis gossypii). The fire ants benefit from the availability of honeydew as a food source, while the aphids benefits from faster population growth (stimulated by the presence of the ants) and continuous ant-provided protection. Credit: Xu et al., 2021, A trail pheromone mediates the mutualism between ants and aphids.
hemiptera-ant mutualism
(a) Ants protect Hemiptera from preying/parasitic predators or parasitic wasps, and hemipterans provide honeydew to ants as food source. Ant predation or harassment on herbivores will have cascading effects on plant fitness. (b) Proposed hypotheses on cascading effects of both native and invasive ants on the local arthropod community and plant fitness. Credit: Wang et al., 2021.

Some Things Can’t Be Replaced

Humans have changed bird communities by driving animals to extinction and introducing species into new habitats around the world. But what happens to the gaps left by extinction events? There has been some debate as to whether introduced species replace the roles of the extinct species, thus maintaining functional diversity within the ecosystem, especially because invasives present often outnumber the extinctions. A recent study examining bird populstions has found that this is not the case.

Each extinct species played an important role in their ecosystem, especially on islands. For example, many ground birds act as grazers, while flighted birds act as pollinators and seed dispersers. Introduced invasives do not seem to be filling in the gaps. Research found that human-driven extinctions have a greater effect on some types of birds more so than others, like ground birds. The research also found that different archipelagoes are becoming more similar as many of the same invasive species are being introduced to different places. Because invasive species are particularly successful at establishing outside their natural habitat, it is not surprising that we see many of the same birds everywhere, such as parrots and starlings. With the same types of invasives establishing themselves on one archipelago to the next, the islands are becoming homogeneous, and the gaps left by extinct species are not being filled.

To read more about the loss of functional diversity through the extinction of island birds, and how it is not offset by invasives: Sayol et al., 2021.

layson rail
Layson rail (Zapornia palmeri). A ground bird that used to inhabit the Northwestern Hawaiian. The population of these birds was totally wiped out due to the introduction of non-native rats in 1944.


Are You Eating My Crops? 7 of 12

The small brown planthopper (Laodelphax striatellus) is a carrier of several viruses that are detrimental to crops. We have passed the halfway mark and are now looking at the seventh headliner in our 12-month series called ‘Are you eating my crops?’ Individual pests chosen for this series have not yet been reported in Texas, but are on the ‘Watch List’ due to their high level of pest importance or risk due to host availability. During this series, we will cover several different crop pests, what to look for, what they look like, and where you can find more information about them. If you ever have question or concerns regarding the headliners of this section, feel free to email

The small brown planthopper is a major pest to rice, wheat, and corn. Most damage to the host plant is caused by viruses transmitted by the planthopper rather than the pest itself. However, L. striatellus nymphs and adults suck the sap from the phloem of the plant. Phloem feeding can cause ‘hopperburn’, the wilting and yellowing of the plant, or ‘sooty mold’. Viruses transmitted by this planthopper include: rice stripe virus (most common), rice black-streaked dwarf virus, barley yellow striate mosaic virus, maize rough dwarf virus, and northern cereal mosaic virus. General symptoms of infection of viruses include stem and/or leaf discoloration, wilting, stunted growth, and honeydew or sooty mold.

The average life span, number of eggs laid, and number of generations is directly affected by temperature and growing season. On average, the L. striatellus lifespan is 18-30 days. In that time, an adult female will lay 70-146 eggs. Adult coloration can range from milky-white to black, but color can vary by season. Adults are most notably identified by the distinct black color of the areas between the carinae of the frons, seen when examining the ventral side of the head (see image to the right). Nymphs undergo four molts, with the development of the fifth instar stage lasting the longest. The nymphal periods can also be affected by temperature. Nymphs are light to dark brown. The fifth instar has extended mesonatal wingpads and dark brown marking on the clypeus, which are distinct from other delphacid species.

Laodelphax striatellus has been intercepted at the U.S. port of entry three times on general cargo. The most likely pathway of entry is on contaminated plant material or by movement of the small brown planthopper specimens in cargo containers. The small brown planthopper is present in numerous countries with a wide variety of climate zones. Corn is commercially grown in every state in the contiguous U.S., wheat in 42 states, and rice in several southern states. Based on climate suitability and host availability, L. striatellus would be able to establish in most of the contiguous U.S.

If you believe you have identified a small brown planthopper infestation or have collected a specimen, please send a picture to

To read more about the small brown planthopper, see the USDA fact sheet.

Laodelphax striatellus MALE.
Laodelphax striatellus frons.
Top: Small brown planthopper (Laodelphax striatellus) male. Bottom: Ventral view of frons. Credit: Glenn Bellis, Department of Agriculture and Water Resources, Canberra, Australia.

Rice stripe virus. William M. Brown Jr.
Rice stripe virus. Credit: William M. Brown Jr.

Never Dump Your Tank in the River

Most aquarium organisms are considered non-native or invasive and do not belong in local water ways, including fish, animals, and plants. Your pet(s) can quickly become a pest with devastating consequences for Texas natural waterbodies if introduced. This is true for both freshwater and saltwater. Never dump your aquarium pets into a natural body of water, or flush them down the toilet.

Plecostomus (Hypostomus plecostomus) and the vermiculated sailfin catfish (Pterygoplichthys disjunctivus), both commonly referred to as armored catfish, are invasive fish that have been found in many rivers. Large armored catfish have recently been caught in the San Antonio River, adding it to the growing list of invaded water bodies. It is believed that these fish are purchased from pet stores and dumped into local creeks or rivers when the fish grow too large for the aquarium. These fish can be harmful to the river ecosystem. Armored catfish burrow into riverbanks, which leads to bank erosion and collapse. This increases turbidity, which can increase water temperature and decrease oxygen levels. Non-native tilapia is also commonly found in the river. These fish are aggressive and can out-compete many of the native species.

The situation in the San Antonio River is only one example of how invasive fish wreak havoc on water ways due to the carless dumping of aquariums. Alternatives to dumping your aquarium: try returning fish to the pet stores or try to rehome them.

armored catfish san antonio river
Armored catfish removed from San Antonio river. Credit: San Antonio River Authority.

Partnering to Address Invasive Species and Forest Health

Webinar Series: December 7, 8, 14, and 15, 2021

ESA and The Nature Conservancy are organizing a short series of webinars focused on the current needs in forest health. These webinars will span from the prevention of introduction of new pests, through detection and management, all the way to reforestation and biological control organisms. While the webinars will be open to the public, much of the content will be technical in nature- therefore forest pest and pathogen subject matter experts are especially encouraged to attend to provide insights and perspectives.

The webinars will be held virtually on December 7, 8, 14, and 15- with moderated presentations and Q&A from 2-4 pm EST, with an open opportunity for informal discussion from 4pm-5pm EST following each. The goal of these conversations is to inform ongoing strategic planning for activities on behalf of ESA’s Grand Challenges Agenda for Entomology and The Nature Conservancy’s Continental Dialogue on Non-native Forest Insects and Diseases. More information and details on the themes and speakers of each of the four days in the series will be available soon at

forest health. USDA Forest ServiceCredit: USDA Forest Service.

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:

  • December 15, 1pm- Classical Biological Control of Weeds- About misconceptions and untapped opportunities. REGISTER.
  • January 19, 1pm- History and effectiveness of injurious wildlife listing under the “Lacey Act”. REGISTER.


How to Get Rid of Hammerhead Worms

You may have noticed a spike in media attention about hammerhead worms, but these long snake-like flatworms have been around since the 80’s. This predatory worm preys on earthworms, secretes chemicals through their skin that can cause skin irritations to humans, and can carry parasitic nematodes within them. All the media attention has been a great help in educating the public and encouraging people to report sightings, which increasing our data collection, and helps expand our knowledge on the worm’s established geological range; however, this doesn’t really help the people that are left with the worms. You should not cut the worm into pieces because each section can regenerate into a fully developed worm within a few weeks. So, what should you do if you find a hammerhead worm?

First, take a picture and report it to Next, collect the worm and place it in a sealable container, such as a zip lock bag or a glass jar. **It is important to note that when handling live flatworms please use gloves, a paper towel, or a stick, and hands should be washed in warm soapy water, and rinsed in alcohol or hand disinfectant.**

Once you have your flatworm in a container, apply salt, vinegar, or orange essence (citrus oil) directly to the worm, seal the container, and place it in the freezer for 48 hrs. The container should then be disposed of in the trash. If a glass jar was used, the container can be washed out, but will need to be disinfected with alcohol or a strong disinfectant. For more information about hammerhead flatworms, see the Texasinvasives info page here.

hammerhead worms. arun T. P.
Hammerhead worm (Bipalium sp.). These worms are typically light/honey colored, with 1 to 5 dark dorsal stripes, and long snake-like bodies. Credit: Arun T. P.

Invasive Spotlight:

Chinese Privet
(Cactoblastis cactorum)

Chinese privet (Ligustrum sinense) is a troublesome and aggressive invasive that spreads easily and crowds out native plants. It often forms dense thickets in bottom-land forests and along fence lines. It is an evergreen shrub with spreading branches and leaves that grow opposite each other with short petioles. The leaves are 2 inches long, ovate or elliptic in shape, usually rounded at the tip, sometimes with a small notch. They taper at the base and have smooth margins. Young twigs are covered with fine hairs that are visible with a 10x hand lens. White fragrant flowers grow to about 3/4 inch wide and are found in narrow clusters up to 4 inches long. Flowers appear from March to May. Blackish blue berry-like fruit grows in clusters that weigh down the branches. The fruit is typically 1/4 inch long and 3/16 inch wide and can be found on the branches until the winter. Chinese privet colonizes by root sprouts and is spread through seed dispersal by birds and other animals. It is shade tolerant, allowing it to invade and spread throughout forest interiors.

Chinese privet is found in southeast and Midwest Texas, as well as 19 other states in the U.S. For more information regarding management and removal, see the info page here. If you believe you have found Chinese privet, please email a picture and the location it was found to

chinese privet. Karan A. Rawlins. university of georgia
chinese privet flowers. Chris Evans. university of illinois
Chinese privet (Ligustrum sinense). Top: Branches with elliptic leaves and berry-like fruit. Credit: Karan A. Rawlins. university of georgia. Bottom: Small white flowers. Credit: Chris Evans.


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

Citrus Greening Workshops

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

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

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

Aquarium Watch: Looking for Prohibited Invasive Aquatic Species

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

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

Air Potato Survey

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

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

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

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

Citrus greening. JM Bove

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

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

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

More News

Texas Man Busted for Keeping Alligator and Several Invasive and Endangered Species At His Home
Texas Parks and Wildlife Department authorities found invasive and endangered species in the home of a Montgomery County resident after receiving a call about the illegal possession of an alligator.

Researcher Works for Diversity and Inclusion in Sciences, One Journal at a Time
Researchers who study invasive species have published a series of articles aimed at addressing concerns about diversity, equity, and inclusion in the one scientific journal, which they believe will lead to a better understanding of invasive species around the world.

History of Insect Invasions Offers Insight into the Future
Scientists with USDA agencies examine the history of live plant imports and invasion by a common group of insects to estimate the rate at which new insects are arriving and how many new insect species may soon find their way into U.S. forests and agricultural fields.

‘Like a Scene Out of ‘Arachnophobia,” Invasive Spiders Take Over Northern Georgia
Joro spiders (Trichonephila clavate) are colorful spiders introduced to Georgia in 2014. Although these spiders have been around for years, they are starting to appear in massive numbers across multiple Georgia Counties.

Magnitude And Timing of Resource Pulses Interact to Affect Horseweed Invasion
A close examination on how variation in magnitude and timing of nutrient pulses effect horseweed (Erigeron canadensis).

AI Helps Record Data on Species to Monitor Biodiversity Over Time
Research teams are deploying autonomous recording equipment in natural areas to eavesdrop on the animals. This data will help answer many important questions.

Montana Lake Study Reveals How Invasive Species Affect Native Food Webs
Invasive species cause biodiversity loss and billions in annual damages in the U.S. alone. Thanks to a new collaborative study, there is greater insight into how invasive species progressively affect native food webs in mountain lakes.

Invasive Species Are Threatening Antarctica's Fragile Ecosystems as Human Activity Grows and the World Warms
With the erection of new research stations, rebuilding, and increased tourism, Antarctica is less isolated than one would think. Humans, cargo, and vessels could be bringing in non-native species that could threaten Antarctica’s fragile ecosystem.

Lionfish- An Invasive Menace Terrorizing Venezuela's Coast
The red lionfish (Pterois volitans) have become a major threat to the western Atlantic Ocean and the Caribbean, from Florida to northern Brazil. How are those in Venezuela coping?

Assessing the Capacity and Responsiveness of Kenya's National Invasive Species System
A recent study has set out to develop a framework and method for assessing the performance and responsiveness of an invasive species system, piloted in Kenya, Africa.


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
Special thanks to Master Naturalists and Master Gardeners

The Texas Master Naturalists and Master Gardeners include multiple groups of well-informed, trained volunteers that provide education, outreach, and service dedicated to the management of natural resources within their communities. They give lectures, create gardens, conduct research, and organize/participate in invasive species removal workshops.

Texas Master Naturalists, along with Texas Master Gardeners, have been a vital aspect of the program and we want to express our deep gratitude for all that you do to protect our state’s natural habitats. was able to present at the Texas Master Naturalist’s Annual Meeting in October, and we received an outpour of support and engagement. Many groups have attributed to the success of, but to see two groups who have continued the battle against Invasive Species since the inception of our program 15 years ago is truly heartwarming. Thank you for all that you do; please keep up the great work, our state needs it!

Always remember you can email to schedule an invasive species presentation or workshop today!


Bucket full of apple snails removed from a residential park in LaPorte, TX. Credit: Ashley Morgan-Olvera.


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:

Invaders of Texas Citizen Science Training Workshop Date: February 19th, 2021
Time: 8:30-12:30
Place: In-person, location TBA
Open to the public. Please register with or Terri MacArthur

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