But for weed warrior Tony Figueroa, this newly sprouted field of distinctive yellow wildflowers is a battlefield.

Mr. Figueroa spent several hours last week spraying herbicide on Tucson’s newest and largest stinkbug, a toxic South African weed that is literally causing headaches in Arizona and California.

Figueroa, invasive plant program manager for the Tucson Audubon Society, said: “It not only poses a threat to the Sonoran Desert ecosystem, but it also poses a threat to human health.”

For those sensitive to it, stinknet can cause skin rashes and asthma attacks. Figueroa says its eponymous odor is subtle, even pleasant at first, but becomes increasingly irritating with continued exposure. will be

Some of his workers complain of headaches after working all day.

To make matters worse, stinknet spreads more easily than other formidable invaders like bafflegrass and takes root even in undisturbed soil. Left unchecked, native plants can quickly squeeze out and take over entire landscapes.

Then, when dried, the oils inside the plant “burn like gasoline,” producing pungent fumes that irritate the lungs, Figueroa said. “There are so many dangers involved in this.”

The Arizona Department of Agriculture has added stinknet to its list of noxious weeds for 2020.

Annuals appear staggered from November to March. At first it resembles the green of a carrot, but grows in dense mats close to the ground until the flowers erupt, giving it another, more attractive nickname, globe chamomile.

No other wildflower in southern Arizona has the same sunny globose blooms. The Arizona Native Plant Society describes them as “little yellow lollipops.”

Each sphere, which ranges in size from a pea to a marble, is actually a small bouquet of about 100 flowers packed tightly together.

Beginning in mid-March, plants produce clouds of “powdered” seeds that are small enough to be dispersed by wind and water or carried by cars, boots and clothing, Figueroa said.

The plant first appeared in Maricopa County in the 1990s and spread rapidly along major transportation routes as its tiny seeds attached to automobile tires and fenders. Within a decade, the yellow flowers could be seen after a wet winter carpet blanketed the glades and highway embankments from the northern tip of Phoenix to Casa Grande.

Stinknet finally arrived in Tucson in 2015, appearing in a vacant lot near Prince and Interstate 10 to the dismay of local plant experts.

Teams currently fighting to curb it include the Department of Agriculture, the Native Plant Association, the National Park Service, Pima County, the Arizona-Sonora Desert Museum, and the Southwest Vegetation Management Association.

Tucson Audubon is covering the cost of equipment, staffing and public outreach with a recent donation of $100,000.

Figueroa said there are about 20 employees dedicated to combating stink bugs and other invasive plants as part of the organization’s mission to protect birds and their habitats.

Tucson Audubon has also launched a website. stinknet.org, helps people identify plants and understand threats. The site includes a map of all locations where stinknets have been found in Arizona so far, as well as an online form for reporting new sightings.

Phoenix has already suffered a Stinknet invasion, but plant experts think Tucson can be saved.

“I think we’re still doing a good job of it,” said Jonathan Horst, director of conservation and science at Tucson-Adubon.

But the cool, wet weather this winter and early spring has brought back weeds. Stinknet has sprung up in several new locations around Tucson. This is nothing compared to the vacant lot west of Stone along Passtime Road. The patch there covers almost two acres and some plants have already seeded.

“This is what Phoenix looks like right now,” Figueroa said on Tuesday, standing on the edge of a vacant lot.

Pima County Natural Resources, Parks and Recreation staff found the largest field of stink bugs in Tucson while driving through their neighborhood about a month ago.

Since then, Figueroa and his crew have found and removed small patches of vegetation at about ten locations within a mile of the main site. They also distributed leaflets to surrounding houses so that residents could pay attention to more weeds.

Figueroa shrugs when asked how long the vacant lot needs to be treated to keep the stink bugs from returning. “Indefinitely,” he said.

While we wait for the next wet and comfortable winter in Tucson, we have no way of knowing how many seeds are already there or how long they will last. It is no exaggeration to say that

“It’s a big effort, but you have to start somewhere,” Figueroa said.