On a recent inspection of an infested Spotted Lanternfly site in Erie County, I witnessed an abundance of Honeydew and Sooty Mold. The owner of the property asked, “What can I do to get rid of it?”
What is Honeydew?
It is a sweet, sticky fluid excreted by insects with piercing, sucking mouthparts. It is a waste product of the plant phloem sap from insects including aphids, soft shell scale, whiteflies, and yes, Spotted Lanternfly.
What is Sooty Mold?
This sugary honeydew coats the leaves below causing a glossy, sticky coating that can attract other insects and lead to the growth of sooty mold, which is a superficial black fungus, which will grow on any surface coated with honeydew.
What insects are attracted?
Bees
Yellow Jackets
Flies
Ants.
These insects just feed on and/or collect the sugar.
What can you do? To get rid of the honeydew, you need to get rid of the source, the insect, in this case Spotted Lanternfly.
I authored an article last year titled “What’s your sidewalk telling you?”
https://bygl.osu.edu/index.php/node/2396
The county had maintenance staff pressure wash the sidewalk, just to have the sooty mold return the next week. This happened several times.
Finally, they treated the magnolia scale on the Saucer Magnolia tree above the sidewalk and the honeydew and sooty mold decreased.
If you have a buildup of sooty mold on hard surfaces, you will need to pressure wash or scrub with soap and water.
Do not Pressure Wash Trees and shrubs!!
To control Spotted Lanternfly adults, Ohio Department of Agriculture recommends the following:
Spotted Lanternflies are susceptible to several management methods. Use the least severe tactic that will give acceptable levels of control.
- When populations are low, acceptable control may be achieved by swatting or stomping nymphs and adults when you see them.
- Removing favored SLF hosts, some of which are invasive themselves (tree of heaven and grapevine, for instance) can result in a reduction in SLF populations on your property.
- The use of lower toxicity insecticides such as horticultural oils and insecticidal soaps can provide control of nymphs and adults, with little residual activity. These products would likely need to be reapplied throughout the season.
- Contact insecticides such as bifenthrin, carbaryl and malathion may be used as spot treatments against SLF nymphs and adults. Repeating treatments may be necessary.
As we approach fall, Adults will begin to lay egg masses. They look like a patch of ‘Silly Putty’ stuck to a tree branch, trunk, metal or stone surface. The egg masses can be scraped off. ODA has the following guidelines:
Managing SLF Egg Masses
Egg masses may be destroyed prior to nymphs emerging, resulting in a reduction in nymphs the following season.
• Egg masses may be squashed—popping the individual eggs within the masses.
• Scraping egg masses with a knife or edge of a credit card into soapy water (dish soap works) or rubbing alcohol will kill the eggs.
• Egg masses may be treated with horticultural oils during the winter months or before bud break in the spring.
In order to get rid of honeydew and sooty mold, you need to get rid of the insect.
In this case, Spotted Lanternfly.
