Above: A group of the late stage 4th instar nymphs of the spotted lanternfly. Photo taken by Vince Burkle (DNR DEPP).
Every few years we seem to be sounding the alarm for a new insect pest (typically an exotic, non-native pest) in Indiana. Although this is not an all-inclusive list, here are five insect pests of concern that are either here already or we fear soon will be: spotted lanternfly, box tree moth, emerald ash borer, Asian long-horned beetle, and the spongy moth.
One of the newer pests of concern is the spotted lanternfly (SLF), first identified and confirmed in 2021 in extreme southeastern Indiana. In July of 2022, it was confirmed along a railroad corridor in Huntington, IN. The insect excels as a hitchhiker and is presumed to have arrived in Huntington via train. “This federally regulated invasive species is a serious new pest that harms plants by slowing their growth and reducing fruit production, especially in vineyards and orchards,” said Cliff Sadof, Purdue entomologist.
The first through third instars (instars are immature and smaller forms of the insect, also called nymphs) of SLF are black with white spots. The fourth instar of the insect is bright red with black and white markings. Adult spotted lanternfly has two sets of wings, and the underwing has a very distinct red color with spots on the outer wings.
Find information on spotted lanternflies at https://ag.purdue.edu/reportinvasive/species/spotted-lanternfly/.
Secondly, a new pest of concern is the box tree moth. Purdue Extension Entomologist and Indiana Cooperative Agricultural Pest Survey Coordinator, Alicia Kelley, reported that it has been found in southern Michigan, but hasn’t been detected in Indiana yet. The larval stage of this moth does extensive damage to boxwoods by skeletonizing leaves, feeding on the bark, and eventually killing the plant. Boxwoods are somewhat common landscape shrubs. Larvae are bright yellow-green with two rows of dorsal black spots. Mature larvae have black and dark green stripes as well. Their black heads have a white “Y” shape in the middle. “They will also use silk to join leaves together for pupation, so the presence of silk webbing is a sign of this pest,” she said. The adults have two color forms, white wings with brown edges and all brown. “Both forms have a characteristic white mark in the middle of each forewing,” she said. Find Kelley’s recent article, “Box tree moth on Indiana’s doorstep,” at https://www.purduelandscapereport.org/.
Thirdly is the emerald ash borer, which has been around for several years now. The question currently being asked is, “Is it worth it for me to continue protecting my ash trees?” The short answer is yes, according to Purdue’s Cliff Sadof and Bob Bruner, who authored an article on this query in a recent issue of Purdue Landscape Report. “Nearly 20 years after its first detection in Indiana (2004), trees still need to be protected to keep them alive,” they said. “The benefits of these living ash trees easily justify the cost of monitoring them.” Removal and replacement costs are two big factors to consider. Read their article entitled, “Should ash trees still be protected from emerald ash borer?” at https://www.purduelandscapereport.org/.
The Asian long-horned beetle (confirmed in Ohio, but not yet in Indiana), is a large black beetle with white spots or blotches and long antennae. Indiana Department of Natural Resources reported that this beetle attacks a wide range of hardwood trees including ash, elm, birch, poplar, and willow, but has a strong preference for maples. Damage occurs as the larva feeds in the heartwood, making branches more susceptible to wind and storm damage. Find more information at https://www.in.gov/dnr/entomology/regulatory-information/asian-longhorned-beetle/.
Last but not least, is the spongy moth, formerly known as the gypsy moth. It is the most serious forest defoliator in the United States. Trees in northern and northeastern Indiana are most commonly affected. Oak leaves are their preferred food, but spongy moth caterpillars can eat the foliage of 500 species of trees and plants. While most trees will produce new leaves after defoliation, repeated annual defoliation may kill trees in two to four years. Whitley County has been added to quarantined counties for the spongy moth in 2023 to limit the artificial spread of spongy moths to other areas. Find more information at https://www.in.gov/dnr/entomology/regulatory-information/spongy-moth/.