October 2017
Zebra Mussel Found in Richland Chambers Reservoir

The invasive zebra mussel (Dreissena polymorpha), which has already been found in at least 17 lakes in Texas, has now also been found in Richland Chambers Reservoir. TPWD fisheries biologists confirmed the presence of six adult zebra mussels in the reservoir October 18 after receiving an identification report from young anglers fishing near the dam. The anglers identified the zebra mussels based on a warning poster they had seen advising boaters to clean, drain and dry.

“At this time it appears to be a pretty low density of zebra mussels and all of the specimens were of similar size, so at this time we cannot say there is a reproducing population in Richland Chambers Reservoir,” said Brian Van Zee, Inland Fisheries Regional Director. “That is why the lake is classified as positive rather than infested, but we do plan to continue to monitor for reproduction.

For more details, read the TPWD news release.

zebra mussel
Credit: Amy Benson, US Geological Survey, Bugwood.org

Richland-Chambers Reservoir
Credit: Larry Hodge, TPWD (retired)

Mexican Fruit Fly Control Needs Citizen Help to Keep Texas Citrus Industry Vibrant

The success of the Texas citrus industry may hinge on a lot of variables, but a tiny fly and people with backyard citrus trees are high on the list.

Allowing fruit to linger on a tree provides a paradise for Mexican fruit flies (Anastrepha ludens) by keeping their reproductive cycle going, but that can slap a quarantine on citrus in the area and limit markets, according to Dr. Olufemi Alabi, Texas A&M AgriLife Extension Service plant pathologist in Weslaco.

“[A] homeowner may have from one to 20 or more trees and not know how to maintain them,” Alabi said. “They don’t know that they have to harvest the fruits by a certain time and that is not only to disrupt the Mexican fruit fly life cycle but to keep the tree bearing for the next season… [W]e strongly encourage homeowners to harvest their fruit whether for consumption or not by April 30 of each year. Even fruit lying on the ground needs to be picked up, double bagged and disposed of properly in the trash."

For more information, read the Texas A&M AgriLife Extension Service article by Kathleen Phillips.

Mex fruit fly
Credit: Bugwood.org

Mexican fruit-fly ad

Removing Invasive Plants Can Increase Biodiversity in Stream Waters

Restoration projects to remove invasive plants can make a positive impact on native plant species. But a new study shows removal of an invasive species growing alongside a stream or river can also improve the biodiversity of aquatic organisms.

Researchers conducted a study to explore whether removal of invasive Amur honeysuckle (Lonicera maackii) shrubs growing alongside a headwater stream in an Ohio forest would influence the diversity of insects, snails, worms and other aquatic macroinvertebrates living in the stream.

A 160-meter stretch of the honeysuckle was removed, which greatly improved the availability of light along the stream and changed the quality of organic matter. Scientists sampled the stream monthly for more than three years. They discovered that removing Amur honeysuckle had a substantial positive impact on the density, richness and diversity of the macroinvertebrates in the stream. "It is clear that removing invasive plants can have a bottom-up impact on adjacent aquatic ecosystems, even when only a small section of the stream is restored," says Rachel McNeish, lead author. "Land managers now have an important new impetus for invasive species management."

Read more at phys.org.

amur honeysuckle
Credit: CarolinaNature.com

Credit: Rachel E. McNeish

Indigenous Nations' Environmental Stewardship in Tackling Invasive Species

As invasive species are threatening ecological habitats throughout the U.S. and Canada, the role of Indigenous nations as environmental stewards has often been overlooked, according to a Dartmouth-led study published in the current issue of American Indian Quarterly.

Past literature has often focused on the sociocultural impact of invasive species on Indigenous peoples, rather than reflecting their knowledge, scientific research and initiatives underway to address invasive species and environmental change, more broadly. As part of their findings, the researchers also aim to help provide a counter-narrative to Indigenous peoples being helpless victims of environmental change.

Through an online survey of over 140 Indigenous respondents, who work in national resource, environmental and cultural departments, the study revealed how the majority consider invasive species a topic of great concern to their community. Environmental, cultural and economic issues were found to be the three areas of concern by priority. The survey results provide examples of the many ways Indigenous nations are adapting to invasive species, documenting their impact and implementing active response strategies.

Read more at phys.org.

Jicarilla Apache Tribe

Free Invasive Plants Tool Kit For Teachers

Science and agriculture teachers across the nation now have a new tool to teach students about invasive plants, thanks to researchers with the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS).

The Florida Invasive Plant Education Initiative at the UF/IFAS Center for Aquatic and Invasive Plants (CAIP) has partnered with The Aquatic Plant Management Society (APMS) to produce a 16-minute video presentation, “Silent Invaders,” for teachers to introduce students to the concepts of invasive aquatic plants and their management with examples from across the United States. “Silent Invaders” provides a basic introduction to invasive plants, along with the key concepts of aquatic versus terrestrial and also native, non-native and invasive plant species, said Dehlia Albrecht, UF’s Florida Invasive Plant Education Initiative coordinator.

Follow this link for more information from IPM In The South.

UF-IFAS logo

Invasive Spotlight:
English Ivy
(Hedera helix)

English ivy is an evergreen woody vine that can climb to 90 feet (28 m) by clinging aerial roots and can form dense ground cover as well. It engulfs and kills branches by blocking light from reaching the host tree's leaves. The host tree eventually succumbs entirely from this insidious and steady weakening. On the ground, English ivy forms dense and extensive monocultures that exclude native plants. English ivy also serves as a reservoir for Bacterial Leaf Scorch (Xylella fastidiosa), a plant pathogen that is harmful to elms, oaks, maples and other native plants. English ivy is toxic to humans when eaten and triggers dermatitis in sensitive individuals.

English ivy spreads locally through vegetative growth, new plants can grow from cut or broken pieces of stems that are able to root in the soil, and it disperses longer distances when seeds are carried by birds that have eaten the berries.

The ivy's thick dark-green leaves have whitish veins and three to five pointed lobes when juvenile. It matures at about 10 years into erect plants or branches with unlobed leaves and terminal flower clusters that yield purplish berries.

English ivy thrives in moist open forests, but is adaptable to a range of moisture and soil conditions, including rocky cliffs, and can tolerate a range of light conditions.

Follow this link for more information on the English Ivy.

English ivy
Credit: James H. Miller, USDA Forest Service, Bugwood.org

English ivy on tree
Credit: Jil M. Swearingen, National Park Service

More News

All of South Carolina Now Under Emerald Ash Borer Quarantine
Effective immediately, the Animal and Plant Health Inspection Service (APHIS) is adding all of South Carolina to the list of regulated areas for the emerald ash borer (EAB) (Agrilus planipennis). APHIS is taking this action in response to the detection of EAB in Greenville, Oconee, and Spartanburg Counties and because the state has decided to establish a full state quarantine. Learn more at www.aphis.usda.gov.

Tsunami Enabled Hundreds of Aquatic Species to Raft Across Pacific
The 2011 Japanese tsunami set the stage for something unprecedented. For the first time in recorded history, scientists have detected entire communities of coastal species crossing the ocean by floating on makeshift rafts. Nearly 300 species have appeared on the shores of Hawaii and the US West Coast attached to tsunami debris, marine biologists discovered. Learn more at sciencedaily.com.

Florida's Burmese Pythons' Predation May Have Consequences for Human Health
As the large, invasive Burmese python (Python bivittatus) eats its way through south Florida's mammals, the mosquitoes in the area have fewer types of animals to bite. Now, more mosquitoes are drawing blood from a rat that carries a virus dangerous to humans. Learn more at sciencedaily.com.

Deer Prefer Native Plants Leaving Lasting Damage on Forests
When rampant white-tailed deer (Odocoileus virginianus) graze in forests, they prefer to eat native plants over certain unpalatable invasive plants, such as garlic mustard (Alliaria petiolata) and Japanese stiltgrass (Microstegium vimineum). These eating habits lower native plant diversity and abundance, while increasing the proportion of plant communities made up of non-native species, according to a new study. Learn more at sciencedaily.com.

Invasive Ladybird Species Threatens Other Ladybirds in England
The harlequin ladybird (Harmonia axyridis) was widely introduced across continental Europe to limit the population of pest insects. New research shows a clear decrease in the numbers of a native ladybird species -- the 2-spot ladybird (Adalia bipunctata) -- on lime trees over an 11 year period during which the harlequin invaded England. Learn more at sciencedaily.com.

Non-Native Species Do Not Make Native Fish More Vulnerable to Pollution in Mediterranean Rivers
The presence of exotic fish in rivers can negatively impact native species in many ways, but new research demonstrates that it does not add to these known problems by altering the native fish response to environmental pollution. Learn more at sciencedaily.com.

Predatory Beetle May Help with Whitefly Control
Research has found an insect predator, Dicyphus hesperus, that may help greenhouse tomato growers manage populations of the sweetpotato whitefly (Bemisia tabaci) when used as a component of an integrated pest management system. Avoiding synthetic insecticides often gives greenhouse tomato growers' crop an edge over field-grown tomatoes, so many growers turn first to biological control. Learn more at ipmsouth.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 become citizen scientists to detect and report invasive species. Workshops, which are free, include information on the Sentinel Pest Network, which serves to increase the awareness and early detection of the Emerald Ash Borer, Cactus Moth, Asian Longhorned Beetle, and other pests of regulatory significance.

Workshops are tailored to meet the interests of your volunteer group, and supplementary session examples include an introduction to the TX Invaders mobile application and the Eradicator Calculator, a feature on Texasinvasives.org designed to help organize and track volunteer-based eradication efforts.

Upcoming Workshops:

Saturday, November 18, 2017
Sentinel Pest Network Workshop
Location: Houston Advanced Research Center (The Woodlands, TX)
Contact: Teri MacArthur

Saturday, January 20, 2018
Location: Headwaters of the Incarnate Word (San Antonio, TX)
Contact: Pamela Ball

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