Invasive Pests on the Horizon

We are all too familiar with the destruction that a single pest or pathogen can bring to our trees. Two of the most evident examples from the recent past would be Emerald Ash Borer (EAB) and Dutch Elm Disease. Thankfully, pests of this significant nature are not common. We can use lessons learned from them to help us manage future issues since we know the importance of proactive management. Now, we are monitoring two potentially threatening insects: a resurgence of Spongy Moth and a potential of a new insect called Spotted Lanternfly.

Adult spongy moth laying an egg mass

Spongy Moth (Lymantria dispar) received a name change early in 2022, previously being known as “Gypsy Moth”. Spongy moth is a non-native, introduced pest in Wisconsin. Their life cycle starts with small caterpillars emerging from egg masses that have overwintered on tree trunks and branches. These caterpillars are voracious leaf eaters and can cause widespread defoliation of mature trees throughout late spring and early summer. Oak trees are the primary food source for the spongy moth, plus maples, walnuts, lindens, and even spruce trees can experience some level of defoliation. 2022 also saw an increased spike of forest defoliation that had not been observed for the better part of 15 years. The weather and other factors can play a variable role in control, but the stage is set for a high level of defoliation this coming year.

The Spotted lanternfly (Lycorma delicatula) is 1 inch long as an adult and has brilliantly colored red hindwings and a yellow and black abdomen. The spotted lanternfly (SLF) continued spreading west in 2022 across Michigan and geographically jumped to Iowa. So far in Wisconsin, only dead adult specimens were positively identified on nursery stock in 2022. This pest has shown a highly invasive nature and it is only a matter of time before SLF becomes an issue in Wisconsin. Adults prefer to feed on grapevines and tree of heaven. The nymphs have a much broader host range and will feed on grapes, hops, roses, and hardwoods, including maple, walnut, willow, and poplar. Feeding can cause tree decline that can lead to mortality.

If you are unsure about how these pests may impact the trees on your property, call Wachtel Tree Science to utilize the ISA Certified Arborists on staff to provide tree and pest identification. We will deliver the best solutions to keep your trees happy and healthy!

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