SLF Egg Masses Begin 2022 Hatch
By: Maria Smith, HCS-OSU
Finally! In the past week, the sun’s come out and so have the growing degree days (GDD). In fact, we have added 80 GDD (base 50 F) in Wooster since Monday alone. We pay so much attention to GDD because it is the primary driver of phenological development for plants. But did you know that it also determines insect lifecycles as well?
…It does, and we can use it to take advantage of when to monitor and manage insect pests in the vineyard. And even if not in the vineyard yet, like Spotted Lanternfly (SLF), we should still be taking advantage of GDD to know when we need to look for various life stages on major host plants.
SLF Egg Hatch prediction map
As of today, SLF range anywhere between about 1% hatch through 100% hatch, depending on location in the state (Fig 1).
Fig 1. SLF Percent of predicted hatch, from https://tools.cei.psu.edu/slf/
What should you be on the lookout for?
Currently, Ohio has 3 known counties with SLF populations: Cuyahoga, Lorain, and Jefferson counties (Fig 2). We expect egg hatch to be further along in Jefferson County than in the more northern Lorain and Cuyahoga counties. It is not unreasonable to suspect that there are other populations out there yet to be identified, therefore it would be prudent to regularly scout for tree-of-heaven (Fig 3) and SLF (Fig 4, 5). At this early point in the season, if you find SLF, you're most likely to encounter older or hatched egg masses (Fig 4) or early instar nymphs (Fig 5). In contrast to egg masses (immobile) and adults (large, showy), newly hatched nymphs are small and mobile, and more difficult to find (Fig 5). At this stage, the first instar nymphs are approximately ¼” in length with black and white spots. They are easily confused with other small insects, but to me look most like ticks. If you have a regular tree-of-heaven that you scout and would like to capture nymphs, using circle traps is one of the preferred methods for catching early SLF nymphs. Circle traps can be purchased through Great Lakes IPM or can be made DIY.
Fig 2. Current SLF distribution map, March 28, 2022. From https://nysipm.cornell.edu
Fig 3. Tree-of-Heaven stand (left) and trunk (right), found near downtown Wooster, OH, October 2021. Tree-of-heaven has shallow-fissured, greenish-brown bark, large compound leaves with two terminal leaflets, and persistent, prolific number of seeds on female trees that develop mid-summer.
Fig 4. SLF egg masses at various ages and coverings. Photo from: https://extension.psu.edu/what-should-you-do-with-spotted-lanternfly-egg-masses
Fig 5. Early instar nymph, SLF, Photo: L. Barringer, PA Dept. of Agriculture, https://bugwood.org
Increasing the search beyond tree-of-heaven (republished from ODA):
Spotted Lanternfly (Lycorma delicatula) has been identified on 172 hosts, some of which were determined to not be hosts on which feeding occurred. Through survey and research observations, there are several hosts on which SLF life stages are seen in higher frequency. Listed below are the hosts which can be surveyed to increase the potential for detection of SLF. SLF population levels and life stage will affect visual survey efforts with lower populations and early instars being more challenging to detect even with the higher frequency hosts at the time of survey.
Egg mass hosts are not listed in terms of high frequency of occurrence as egg masses can be found on many different tree and plant species as well as inanimate objects.
Penn State Extension Spotted Lanternfly website, Spotted Lanternfly Management for Residents, Landscape Professionals, Vineyards
Houping Liu, Seasonal Development, Cumulative Growing Degree-Days, and Population Density of Spotted Lanternfly (Hemiptera: Fulgoridae) on Selected Hosts and Substrates, Environmental Entomology, Volume 49, Issue 5, October 2020, Pages 1171–118
Houping Liu, Richard Hartlieb, Spatial Distribution of Lycorma delicatula (Hemiptera: Fulgoridae) Egg Masses on Tree-of-Heaven, Black Walnut, and Siberian Elm in North America, Journal of Economic Entomology, Volume 113, Issue 2, December 2019, pages 1028-1032.
Joseph Keller, J. Rost, K. Hoover, J. Urban, H. Leach, M. Porras, B. Walsh, M. Bosold, and D. Calvin, Dispersion Patterns and Sample Size Estimates for Egg Masses of Spotted Lanternfly (Hemiptera: Fulgoridae), Environmental Entomology, Volume 49, Issue 6, October 2020, pages 1462-1472.
Lawrence Barringer, Claire M Ciafré, Worldwide Feeding Host Plants of Spotted Lanternfly, With Significant Additions From North America, Environmental Entomology, Volume 49, Issue 5, October 2020, Pages 999–1011.
If you suspect presence of SLF, report your findings to the Ohio Department of Agriculture by calling 614-728-6400, emailing email@example.com, or filling out the online report. Sightings of all invasive species in Ohio can be reported using the Great Lakes Early Detection Network App, which can also be used to report repeated negative or positive findings of tree-of-heaven and SLF. Please take photos and exact locations (GPS, identifiable landmarks, etc.) to file with your report.