Fall yard work and maintenance can be a key time to remove and prevent the spread of invasive species and diseases, according to guidance from the Iowa Department of Natural Resources.
Invasive species like bush honeysuckle are easy to spot and yank out during the fall and funguses like oak wilt can be best managed by pruning during cooler temperatures. Iowans should also be on the lookout for things like zebra mussels as they pull boats and other equipment out of the water.
The Iowa Department of Agriculture and Land Stewardship confirmed Friday that the invasive spotted lanternfly has been identified in Iowa. IDALS urged Iowans to keep an eye out for the insects that can be destructive to vineyards, orchards and forests.
These Asian-native insects like to cluster on the trunks of their favorite food, tree of heaven. The lanternflies have brown outer wings with dark spots and bright red and black inside wings that can be seen when the lanternflies open their wings. In nymph form, the lanternflies are black with white spots and turn red as they get older, according to photos from the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service.
The insects excrete a sticky “honeydew” substance that can be seen near the plants that a colony has infected. They also create spots of mold that look like soot along the plant and its fruit. As nymphs, the insects gather in large clusters on a plant, which can make them easy to spot.
While the insect prefers tree of heaven, which IDALS said is common in alleyways, unkept urban areas and fence rows, they can feast on around 70 plant species.
The spotted lanternfly was introduced in Pennsylvania in 2014 and is now present in 20 states. The insect was seen and confirmed in Des Moines County in September, but state entomologists have not seen signs of ongoing infestation in the area.
IDALS encourages Iowans who identify the spotted lanternfly to contact IDALS at (515) 725-1470, Entomology@IowaAgriculture.gov or their local Iowa State University extension office.
When bringing outdoor equipment inside, or transporting in the fall and winter, APHIS recommends scanning the items for “egg masses,” which look like smears of mud. These masses should be crushed and scraped into a sealable plastic bag and then thrown away to prevent the spread of spotted lanternfly.
Clean boats and water equipment for zebra mussels
Boats, trailers, docks and lifts in Iowa’s lakes and rivers should be thoroughly checked and scrubbed down for zebra mussels before being stored for winter, DNR advises.
DNR’s Aquatic Invasive Species Coordinator Kim Bogenschutz said the winterization process is “a great time” to check for new infestations.
“As you bring each item out of the water, visually inspect areas that have been submerged for months,” Bogenschutz said in a news release from DNR. “Juvenile zebra mussels should be visible this time of year, but also run your hand over smooth surfaces to check for very small juvenile zebra mussels that feel like sandpaper.”
Zebra mussels are expert hitchhikers, which is why boat owners are instructed to clean, drain and dry all of their equipment before leaving a water body. Equipment like bait buckets should also be emptied and cleaned. According to DNR, it is also illegal to introduce any live fish, except for hooked bait, into public waters.
Zebra mussels, once introduced to a water body, can build up dense clusters, increase algal blooms and interfere with the aquatic food chain.
DNR has confirmed the presence of zebra mussels in nearly 20 Iowa lakes and nine rivers. Most recently, the department found the mussels in Saylorville Lake.
Pruners, herbicide and rakes
As most plants and leaves turn brown in the cooler months, the plants that keep their leaves a bit longer tend to pop out of the landscape.
DNR said this is the case with bush honeysuckle, a deciduous tree native to Eurasia that will outcompete Iowa native plants in a landscape and is therefore considered invasive.
Bush honeysuckle plants will hold their leaves well into November, while native varieties’ leaves will drop off. The bush honeysuckle can also be identified by breaking off an older stem. According to DNR, bush varieties will have a hollow, brown core while native varieties will be solid.
Smaller plants can be pulled out, while more substantial growths of bush honeysuckle will need to be chopped at the roots, or cut near the base and hit with an herbicide solution.
Glossy buckthorn is also easy to spot in the cooler months when surrounding vegetation drops its leaves. This small tree or shrub has a brown-gray bark with lighter colored pores and a bright yellow and orange sapwood, the wood just inside the bark.
These plants can similarly outcompete native species and cause shaded forest floors where other plants have difficulty surviving. According to Iowa State University, the plants are also a host to soybean aphids.
Iowans can remove glossy buckthorn by chopping it at the base of the plant and coating the exposed stem with herbicide, or by coating the lower 12 to 18 inches of the stem with an herbicide. If the herbicide is dripping off of the plant, it has been over applied, which can be damaging to the surrounding environment.
DNR also recommends pruning oak trees during colder temperatures to prevent the spread of oak wilt, a fungus that can cause oak trees to wilt and eventually die.
Tivon Feeley with DNR’s forest health program said pruning outside of the oak tree’s growing season is the best way to prevent the spread of the disease.
Black oak, pin oak, and red oak trees are most susceptible to the fungus and will typically die within the same season they are infected, according to DNR. White and bur oak varieties can live with the fungus for a number of years before the disease takes over.
Open wounds in the tree during the growing season can easily be infected by small beetles that carry the fungus spores from one tree to another, which is why DNR recommends pruning outside of the growing season.
“It’s best to wait until after Oct. 15 to start pruning oak trees,” Feeley said in a news release. “You can prune your oaks all winter long with the goal to stop pruning by March 1.”
Trees can also be infected by root grafts that connect to nearby, infected trees.
Infected trees will have leaves that bronze along their outer margins and defoliation will begin at the top of the tree.
Pruning trees and dealing with invasive species in the yard might sound like a lot of work, but DNR said these chores could replace one of the most dreaded fall activities: raking and bagging leaves.
According to the department, leaving some leaves and yard waste in strategic areas can provide insulation for trees and wildlife and benefit the soil.
A newsletter from DNR suggested leaving an unmown area of the yard, away from the house, to collect leaves and branches that will provide shelter for critters during the winter. As the leaves sit there, they will break down into a loam that can be beneficial for flower beds or planters come spring.
