A note sent to Bugwood to update their Spotted Lanternfly information about what I have found while doing field research.

1. Spotted Lanternfly research note
Richard Gardner
August 24, 2019
The Spotted Lanternfly from my experience it is not a threat to forests and just because it is on a plant does not
mean it feeds on that plant. I have photos of SLF on a telephone pole and on rusted iron fence posts. What I have
seen is it will lay eggs on a food source, but very often on trees around a food source. An interesting quirk I am
seeing is that it does not feed on forest trees, but will feed on the same genus if it is in a domesticated situation.
SLF is primarily an insect of edges and ecotones such as fields edges, hedgerows, urban and suburban forests
which is where its primary food sources, Ailanthus altissima and Vitus sp. grow. Locally, I have also seen nymphs
and adults on Black Walnut (Juglans nigra). The few times I have seen SLF in a forest it was probably carried
there on a hiker, a hunter or vehicle. The gypsy moth is a much greater threat to our forests.
My understanding is that there are 5 nymph stages with instars 4 and 5 being red. Adults apparently have 2 or 3
stages from just emerged to mature. I am still working this out as I often see two and possibly 3 different adult
sizes. Along with this, I have seen two or three life stages such as two or more instars, adults and a late stage
instar and two sizes of adults at the same time.
The quarantine is a sad joke. SLF has spread into Delaware and New Jersey, possibly New York and has been
found in Maryland and Virginia. Scraping the billion or so egg masses in Berks County, PA is a completely lost
cause as that would require exploring every square meter of land in this area and eliminating every food source.
Reproduction - From my observations SLF just needs a good food source to produce fertile eggs. Locally, I saw
egg masses over the winter which hatched in the late spring and this past Wednesday adults in an area where
there are no Ailanthus trees, just wild grape.
Talking with local wineries, SLF is a major threat to them. However, talking with a local orchard, not a threat to
peaches and apparently other tree fruit. The past winter with a late hard freeze and the unusual amount of rain
over the past couple years has done more damage than SLF to local grape vines.
There appears to be a wave phenomenon with SLF where the population builds up in an area, explodes and then
virtually disappears. This needs a few more years to follow to be absolutely certain if is a long term phenomenon.
I can now locate an Ailanthus tree where SLF congregate by the smell from many feet away. In the winter I look
for the black sooty mold at the base of an Ailanthus tree from earlier feeding.
About two weeks ago, the adults started dispersing across the landscape. They nymphs and early adults may
disperse in a small area. However, mature adults disperse more widely. (I have seen nymphs in the same spot
over several weeks.) What was backyard research, with eggs, nymphs and adults this morning became back
deck research as there were many adult SLF on wild grape overhanging our deck.
We live in northern Berks County just south of Shartlesville. My MS thesis, University of Maryland, completed in
2008 was ironically on Ailanthus altissima.