Iowa DNR: Watch out for invasive species, diseases while winterizing

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 Des Moines County in southeast Iowa. IDALS urged Iowans to keep an eye out for the insects that can be destructive to vineyards, orchards and forests.

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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.

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The insect 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.

Two immature lanternflies were identified in 2022 in Dallas County near Des Moines.

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.

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.

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 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.

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.

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.

“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.”

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.

This article was first published by Iowa Capital Dispatch.