Archive for the 'Texas Invasives' Category

Challenges of Controlling Feral Swine

Thursday, August 16th, 2018

Herd of feral hogs.

This is Passport

Trapping and hunting are not effective controls against feral pigs.

These methods have not been able to reduce the geographic spread and the increase and abundance of feral pigs in our state, nationwide, and – I’m sorry to say – globally.

Justin Foster, research coordinator at TPWD for region two, says we need new tools to combat the pigs. The agency is evaluating sodium nitrite based pig toxicants.

What we don’t have is a tremendous amount of information that tells us that we can deliver any pesticide safely, reliably and humanely.

They’re collecting that data now. During one field test the pigs dropped baits, perhaps detecting a difference between the placebo and poison versions. This lead to unintended costs for passerine birds.

And so, as this bait was being dropped, and those feral pigs were going back to the feeder to try some more—it wasn’t so bad that they weren’t trying more—they were trampling the bait that had been dropped. And that bait had some grain in it. We assume those passerine birds were targeting that grain.

Researchers do not take such losses lightly, and continue to work on a reliable and humane protocol.

The Wildlife Restoration program supports our series and funds the development of toxicants and delivery strategies for controlling feral hogs in Texas.

For Texas Parks and Wildlife, I’m Cecilia Nasti.

Controlling Feral Swine in Texas

Wednesday, August 15th, 2018

Feral Hogs at the Kerr Wildlife Management Area

This is Passport

Feral hogs account for more than $52 million dollars in damage to Texas agriculture annually. The cost to habitat and wildlife is incalculable. While Texas has more feral swine than any other state, we don’t know their numbers.

Estimates at the statewide scale are pretty loose. And I’d kind of like to leave it at that.

Justin Foster is research coordinator at TPWD for region two. He said some estimates suggest upwards of 3.5-million feral pigs roam Texas.

Their impacts are certainly well documented and widespread. And, I think all of them [impacts] are not identified yet.

They may, in fact, be doing more harm than we know. These animals are adaptable, robust, and are reproductive stars. Populations vary due to wide-ranging resource conditions. Hunting is not effective when it comes to reducing their numbers. So, Texas Parks and Wildlife is studying the use of a toxicant to control them.

We’re talking about, literally, a pesticide. It is an active ingredient that is targeted to produce a lethal outcome for the purposes of control. In this case, that active ingredient that our work centers around is sodium nitrite.

Tomorrow: the trial and error process of finding an effective control.

The Wildlife Restoration program supports our series and funds the development of toxicants and delivery strategies for controlling feral hogs in Texas.

For Texas Parks and Wildlife, I’m Cecilia Nasti.

Tilapia: Detrimental and Delicious

Thursday, July 26th, 2018
Blue tilapia

Blue tilapia

This is Passport to Texas

When you hear the word tilapia, you may think of a savory meal with lemon butter sauce, but you probably don’t think of the term “invasive species.”

Tilapia are great to eat. They’re raised as a food fish, and they’re quite tasty. They’re quite popular in restaurants. But the problem is when they’re in our natural waters they are upsetting the ecosystem.

Originally established in fish farms as a food source, Tilapia eventually found their way into Texas waters.

Gary Garrett, a former Texas Parks and Wildlife fisheries biologist, says tilapia pose a threat to large mouth bass and other native species.

They build big pit nests and in doing that they stir up a lot of the sediment. And it’s been shown, for example, with large mouth bass, all that sediment stirred up and settling back down will often kill largemouth bass eggs.

And because of the delicate nature of the food chair, this behavior has the potential of damaging the entire ecosystem.

TPW has regulations for tilapia, but because they’re widespread statewide, they are difficult to control. But if you like to fish, Garrett says, there’s one way you can help.

Don’t throw them back. If you catch them, keep them.

So, next time you reel in tilapia, turn on the grill and get cooking.

The Sport Fish Restoration Program supports our series.

For Texas Parks and Wildlife…I’m Cecilia Nasti

How to Spot the Cactus Moth

Wednesday, July 18th, 2018

Photo credits: (top) Susan Ellis, USDA APHIS PPQ, Bugwood.org; (mid) Jeffrey W. Lotz, Florida Department of Agriculture and Consumer Services, Bugwood.org; (bottom) CMDMN

This is Passport to Texas

Prickly pear cacti are economically important to Texas and Mexico. They’re also the larval food of the cactus moth, a nonnative species that’s heading to Texas.

Invertebrate biologist Michael Warriner says the larvae of this prolific South American moth species, which is active this time of year, can decimate prickly pear populations. The adult insect is non-descript and difficult to identify, but the larvae is easier to recognize.

Looking for the larvae or evidence of feeding damage is the best thing to look for. The caterpillars themselves are a bright orange to red coloration with black bands or spots. The larvae spend most of their time inside of the prickly pear pad, and they basically hollow it out. So the pad, as the larvae feed on it, will become transparent and they’ll eventually just collapse.

Researchers are developing methods of managing the moth. Until then, if you see infested plants…

You can still control it by removing the infested pads and that would help. Disposing and burning them. Or simply enclosing them in some kind of plastic bag to heat up the larvae and kill them.

Find links to more information about the cactus moth at passporttotexas.org.

The Wildlife Restoration program supports our series.

For Texas Parks and Wildlife…I’m Cecilia Nasti

A Pest With a Passion for Prickly Pear Cactus

Tuesday, July 17th, 2018

Map from presentation by Kristen Sauby, from her presentation to the Ecological Society of America Annual Meeting.

This is Passport to Texas

There’s a moth making its way to Texas from Florida whose larvae feed exclusively on prickly pear cactus.

The cactus moth has proven to be a really effective eradicator of prickly pear.

Invertebrate biologist, Michael Warriner, says Australian officials imported the cactus moth—a South American native—in the mid-1920s as a biological control against the coastal prickly pear; a nonnative species they had imported in the early 1800s.

And over a few years, it didn’t totally eliminate it, but it reduced it substantially. So, it’s proven to be one of the most successful biological control agents, as far as insects go.

The moth, discovered in the Florida Keys in 1989, may have arrived on imported prickly pears, and since then has spread up to South Carolina and over to Louisiana.

So, the concern is that if it makes it to the southwestern United States and Mexico that it could have a similar impact and eradicate or reduce prickly pear; and the fact is that—for Mexico especially—prickly pear is a major agricultural commodity in the tens of millions of dollars in terms of value. And it’s worth millions of dollars in the US, too: for agriculture and biodiversity and landscaping.

Tomorrow: How to identify and prevent the spread of the cactus moth.

The Wildlife Restoration program supports our series.
For Texas Parks and Wildlife…I’m Cecilia Nasti