Invasive plants benefit ticks

PANA, Ill. — Invasive plants are a threat to the natural ecosystem.

“Fescue is not native to Illinois,” said Teresa Steckler, University of Illinois Extension commercial agriculture educator. “It was introduced as erosion control and now it’s everywhere.”

There are numerous invasive plants in Illinois that are changing the ecosystems, Steckler said at a presentation during the Dudley Smith Farm Winter Meeting.

“Some of them are Autumn Olive, multiflora rose, thistles, reed canary grass, Johnson grass and kudzu,” she said.

“There is also Japanese barberry that we see cover the floors of forests,” said Steckler during the virtual event. “Bush honeysuckle will completely invade a woods in 10 years and it sterilizes the soil which prevents normal flora from growing.”

U of I researchers are working to understand the relationship between invasive plants and tick-borne diseases.

“When you have an increase in the environment for the tick, an increase in the environment for small rodents and birds and an environment that’s changed for the deer, they all interplay to affect the prevalence of ticks,” Steckler said.

Each tick carries its own specific disease.

“If you get bit by a tick, pull it off with a pair of tweezers, put it in alcohol and save it,” Steckler said. “If you have any flu-like symptoms within two weeks, take the tick in because it can help the doctors identify what disease the tick could be carrying.”

According to data from the Centers for Disease Control and Prevention, Steckler said, Lyme disease cases have increased by over 500,000 in the United States.

“In Illinois it has increased by 15 to 20%, so it is something everybody needs to be aware of,” she said. “Tularemia is in pockets of Illinois.”

As humans and dogs are enjoying a wooded area, they have the potential to come in contact with a tick that is infected with Lyme disease.

“Ticks sit on the end of sticks, usually on paths where they are attracted to carbon dioxide,” Steckler said. “They wait for shadows to come along and then they latch onto an animal or person.”

There are many factors that effect if there is a presence of disease in a tick population.

“Ticks need a food source, the right habitat, proximity to infected hosts and access for transmission to humans,” Steckler said. “It is also effected by the percent of the population infected and the activity of the ticks because ticks aren’t going to be active when it is cold.”

When the temperature rises to the mid-40s, Steckler said, they will become more active.

“To have a really good tick population you also need higher humidity,” she said. “In a hot, dry summer there will not be a lot of ticks.”

Ticks need access to small mammals and birds, as well as larger mammals such as deer or cattle, for the adult stage feeding.

“Humans and dogs are usually dead-end hosts,” Steckler said. “Dogs are typically treated with chemicals to kill ticks and when humans get bit the tick is killed by the person.”

A closed canopy in a woods increases the humidity which could increase the tick population.

“An increase in invasive shrubs compared to native shrubs will increase the density and humidity and therefore increase the host populations and tick populations,” Steckler said. “It’s a vicious cycle, so we want to look for ways to change those situations.”

Bush honeysuckle has the ability to overtake an area in a short period of time.

“If you don’t want to use herbicides to control it you have to dig the roots out,” Steckler said. “If you just cut it down, it will keep coming back.”

Steckler is working on a project that will start in March to examine the relationship between different invasive plants including shrubs and grasses and the prevalence and diversity of tick species associated with human and animal pathogens in Illinois.

“We plan to determine the abundance of tick species at our sampling sites,” she said.

The researchers are going to be evaluating several sites located near Decatur and at the U of I Dixon Springs Agricultural Center. The researchers plan to drag for ticks at Dixon Springs in March and near Decatur in April.

“We are going to collect the ticks, figure out what species are there and analyze the ticks to determine the diseases that will affect cattle and humans,” Steckler said. “We’re also going look at temperature and humidity at the sites to relate that back to the ticks we are seeing and the prevalence of diseases that these ticks are carrying.”