Today’s installment of the EnvIowa podcast features an interview recorded Feb. 7 with Dr. Andrew Forbes, an evolutionary ecologist at in University of Iowa biology department. Forbes chats about the ecological importance of parasitic insects and shares insights about other creepy crawlies like emerald ash borers and periodical cicadas.
Listen to learn more about his work on insect diversity and speciation.
Invasive species often travel across continents via human transportation vessels and the cargo they carry. These species often have no natural predators in their new homes, so their populations explode. The native species that the invaders in turn prey upon are not adapted to defend themselves against these new predators, giving the invasive species an advantage over the native predators that now must share their prey. The result is a devastating chain reaction that can ripple through entire ecosystems.
Iowa Governor Kim Reynolds declared May Invasive Species Awareness Month to encourage the public and private sectors to join forces and amp up the fight against ecosystem invaders. Invasive species in Iowa harm agriculture and seriously degrade state parks, which are a source of tourism revenue.
One of Iowa’s most problematic invasive pests is the Emerald Ash Borer, a beetle from east Asia that has killed millions of ash trees across the country in the last 17 years. Another common offender is Garlic Mustard, a tasty herb which is spreading rapidly through Iowan woodlands and crowding out native plant species. A full guide to problematic invasive plant species found in Iowa’s woodlands can be found here.
Gardeners will be familiar with many invasive bugs and weeds, like the Japanese Beetle, the Brown Marmorated Stink Bug and bull thistles. These pests and others can pose real threats to Iowa farmers, and many are tracked by the Iowa State Ag Extension Office.
How can you help?
Do not buy or sell firewood from outside your county. Firewood can contain and spread invasive insects like the Emerald Ash Borer.
Scrub shoes and clean clothes before and after trips outdoors to avoid spreading seeds, especially when visiting public lands.
Remove invasive plants where you recognize them. Some groups and parks host volunteer days to pull invasive species.
Researchers at Iowa State University are studying a stingless wasp species as a way to combat agricultural pests such as the soybean aphid.
Aphids began posing a serious threat to Iowa soybeans around 2000. Since that time the invasive insects have reduced crop yields by 40 percent during outbreaks and have led to a 130 percent increase in insecticide use on affected fields. The aphids are native to Asia and are suspected of being brought to the United States by travellers transporting plants.
The researchers are studying the Aphelinus glycinis, a stingless wasp that serves as a predator to aphids, at ISU-affiliated research farms this summer. Not only will the researchers be studying the effectiveness of the Aphelinus glycinis in reducing aphid populations but they will also study ways the Aphelinus glycinis responds to the environment and affects Iowa’s ecosystem.
The research team consists of Matt Kaiser, a pre-doctoral associate in ISU’s Department of Entomology; Matthew O’Neal an associate professor in the Department of Entomology; and Keith Hopper, research entomologist for the U.S. Department of Agriculture. The idea of introducing one species as a way to reduce the population of an invasive species is a concept known as “biological control.”
“If there’s a pest causing harm to humans or the environment, you can find other organisms that reduce that harm by suppressing the pest’s population. That’s what we refer to as biological control,” Kaiser said.
Officials in Iowa will be releasing thousands of tiny, stingless wasps in the next few weeks as a way to combat the invasive emerald ash borer (EAB).
Iowa officials will introduce two species of parasitic wasps to deal with the EAB infestation that has been recorded in 31 of Iowa’s 99 counties. Each wasp species, which are harmless to humans and about the size of a grain of rice, will attack the EAB in two ways: one by laying eggs inside EAB eggs and the other by laying eggs in the EAB larvae. Both species also use the EAB to feed its offspring.
Officials with the Iowa Department of Agriculture and Land Stewardship will release the wasps into a 133-acre wooded area near Fairfield in Jefferson County. The Jefferson County site will be part of a four-year effort that involves releasing the wasps into the environment and monitoring their affects on EAB populations. Officials have also considered releasing wasps in Allamakee County where the EAB was first detected in 2010.
The invasive emerald ash borer (EAB) has made its way into Johnson County, according to officials with Iowa’s Department of Agriculture and Land Stewardship.
Facilities Management crews for the University of Iowa made the discovery this week after noticing woodpecker activity on the upper branches of an ash tree south of the campus’ Main Library. The east Asian beetle was first sighted in Iowa City by a resident 19 months ago, however officials at the time were unable to find signs of a larger infestation.
UI Facilities Management crews plan to remove the campus’ more than 550 ash trees in the coming years. Ash trees make up roughly seven percent of the tree species on campus including areas along the T. Anne Cleary walkway as well as the Pentacrest. The cost for the project is unknown but is expected to be “hundreds of thousands of dollars.” Officials have discussed the possibility of the using the trees they remove as a fuel source for the UI Power Plant.
This is at least the second mass removal of trees on the UI campus during its nearly 170-year history. More than 2,000 American elms dotted the UI campus prior to an outbreak of the Dutch elm disease during the 1960s and 70s which wiped out all but two trees. Those two trees still stand today with one on the Pentacrest and the other near Rienow Hall.
The EAB was first discovered in Iowa in 2010. Johnson County is now the 30th county in the state to report an EAB infestation.
Dr. Darren Ranco visited the University of Iowa campus this week and on Wednesday night gave a lecture on the emerald ash borer and how it is affecting Native American basketmakers in his home state of Maine.
Ranco is a member of Penobscot Indian Nation and holds a PhD in social anthropology from Harvard University. He is currently the Chair of Native American Programs at the University of Maine and also serves as an associate professor in anthropology. Much of his research focuses on issues of environmental justice for Native American populations. On Wednesday he presented “Wabanaki Diplomacy to Protect the Ash Tree: Sustainability Science and Environmental Justice in Maine” as part of the UI’s Ida. C. Beam lecture series.
He began by discussing the infestation of the emerald ash borer in the United States which was first reported in Michigan in 2002 and has since spread as far west as Colorado and as far east as New Hampshire. In Iowa, the emerald ash borer has been reported in nine counties (Allamakee, Black Hawk, Bremer, Cedar, Des Moines, Jasper, Jefferson, Union, and Wapello).
“The upper part of the Midwest here has a pretty high density of ash trees compared to other places so the rate of spread, in terms of creating a large number of bugs because there’s a lot of food they can eat, is also part of the spread dynamic,” he said.
The spread of this species, which is native to China, can also largely be attributed to the transportation of fire wood. Public education campaigns have been launched in an effort to fight the dissemination of the bug with much of the focus on prevention as opposed to eradication.
“The biggest thing that makes it really imposible to fight in a conventional forestry way, in terms of eradication, is simply it’s just so hard to detect at low density,” he said. “By the time it’s in a place after three to five years and kills a tree there’s just no response you can have.”
He added that foresters can sometimes catch the bug before it becomes a problem but it is considerably more difficult for landowners and other members of the public to detect it. The bugs themselves do little damage when eating the tree’s leaves however the larvae burrow underneath the tree’s bark which inhibit the tree’s ability to retain necessary nutrients.
Though the emerald ash borer hasn’t made its way to Maine yet, Ranco and his colleagues are working to make sure they are prepared for the bug’s inevitable arrival. For the past five years, Ranco has conducted research using a combination of sustainability science and indigenous research methods to find solutions for tribal basketmakers, landowners, and others who would be affected.
“Maine is a huge forestry state but ash trees are not a central part of our forests. It’s only about four percent of our forests that are ash trees,” he said.
Because of the lack of ash trees specifically in Maine, Ronco said officials with the state’s forestry industry have been slow to respond to the treat of the emerald ash borer. However, Native American tribes in the area often use brown/black ash trees (fraxinus nigra) to construct wood baskets and a loss of ash trees would mean a loss of this cultural tradition as well as a source of income for some. Regardless of the challenges they face, Ranco said he is confident that Mainers will be prepared for the arrival of the emerald ash borer.
“Once the EAB gets there it wont be just a bunch of politicians and bureaucrats lighting their hair on fire, we will actually know what to do.”
The pesky and invasive emerald ash borer is moving west across the state and could become problematic for parts of central Iowa, according to a recent article in the Des Moines Register.
The infestation of this Asian beetle began in Michigan in 2002 and has now migrated as far west as Newton, Iowa which is about 30 miles east of Des Moines. The emerald ash borer was first sighted in Iowa in 2010 and has since spread to at least nine Iowa counties including Allamakee, Black Hawk, Bremer, Cedar, Des Moines, Jasper, Jefferson, Union, and Wapello. State and federal officials worked together to draft a readiness plan and as of February 2014 the entire state was placed under quarantine to prevent further infestation into neighbouring states. The bug – which fully grown measures about one inch in length – “poses a 100 percent threat of death to ash trees if not properly confronted. “
An informational meeting to discuss ways in which to combat this invasive species will take place at the Ankeny fire department headquarters (120 N.W. Ash Drive) in Ankeny at 5:30 p.m. tonight.