Spotted Lanternfly Damage

Spotted lanternflies are a significant economic and lifestyle pest for residents, businesses, tourism, forestry, and agriculture. Their presence has led to crop loss, exporting issues, and increased management costs.

While the list of spotted lanternfly host plants is long, the greatest agricultural concern falls on grapes.

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Should I worry about spotted lanternfy?

They don't bite or sting but their large numbers and messy honeydew can be a nuisance.

a large tree trunk completely covered with adult spotted lanternflies

Swarm Feeders

Spotted lanternfly feed in large numbers, which can be a nuisance.

front view of black bug feeding on a twig with small orange spots that look like eyes but are antennae

Feeding Damage to Plants

Spotted lanternflies do not appear to be damaging trees or most agricultural crops but are having an impact on grapes and some other crops.

an adult spotted lanternfly and a yellow jacket

Honeydew

Sooty mold grows on the honeydew excreted by spotted lanternflies. Honeydew also attracts other insect pests.

Grapes

Spotted lanternfly has proven to be a serious pest of grapes (both cultivated and wild). They are swarm feeders and up to 400 Spotted lanternfly adults per vine have been reported. Feeding by a population this high has been shown to weaken the vine, leading to loss of winter hardiness, reduced or no return bloom or crop, and even vine death.

Feeding Damage to Plants and Crops

Spotted lanternflies do not appear to be damaging trees or most agricultural crops. In natural and residential areas, they feed on Tree of heaven (Ailanthus), black walnut, maples (they will preferentially feed on silver maple, then red maple), willow, river birch, black cherry, tulip poplar, and other trees.

They don't seem to be causing significant damage to agricultural crops such as hops, apples, or peaches, but the issue is still being studied.

More information about spotted lanternfly host plants.

Spotted Lanternfly Host Plants

Feeding Behavior

First through third instar nymphs feed on young shoots of perennial and annual plants while the stronger-beaked fourth instar nymphs and adults are able to feed directly on older tissue. Spotted lanternfly feeding damage can deplete reserves and stored starches in affected plants which can be serious for sensitive plants, such as grapes.

Feeding by Spotted Lanternfly may cause

Oozing
Wilting
Defoliation
Dieback
Yield loss or quality reduction
Reduction of cold hardiness
Plant death

leave covered with a dark sticky looking residue and a spotted lanternfly

nysipm - spotted lanternfly honeydew on stairs

Honeydew, Sooty Mold and Stinging Insects

Because spotted lanternfly consumes large quantities of a plant's sugary sap to extract nitrogen and amino acids, it expels large quantities of excess sugar-water (honeydew). Honeydew—often misidentified as sap—shows up on outdoor equipment, decking, vehicles, pets and your clothing and hair. Left to accumulate outdoors, honeydew acts as a growth medium for thin, dark layers of sooty mold fungi.

Abundant excretions of sticky honeydew by swarms feeding on shade trees, and the associated growth of sooty mold, can restrict people’s enjoyment of parks and their own backyards. Honeydew can also produce an odor of fermentation which can attract other nuisance insects, such as bees and wasps. This creates an increased stinging risk around infested plants.

The combination of honeydew and sooty mold production has a negative effect on the quality of life for residents in areas with high populations of spotted lanternfly and can have some residents feeling like prisoners in their own homes, from late summer until the first hard freeze kills the adult spotted lanternflies.

Sooty mold damage to crops

Though no life stage of the SLF feeds directly on fruit, sooty mold growth on the skins of grapes and tree fruit can make crops unmarketable. Sooty mold can also inhibit the photosynthetic capacity of leaves.