Spotted Lanternfly Summit – Day 1

Recorded March 1, 2021

Download the agenda (PDF)

Q&A Day 1 – Research

Compiled by Nancy Cusumano, Northeastern IPM Center

Q. Will this research be published in a paper?

A. I know Dennis Calvin was working on a publication.

Q. Why is the base temp = 8.14 C being used to calculate SLF GDD development but base temp = 10.4 C being used for geographic models?

A. Answered live.

Q. At one point, I think I remember that there was an estimate of a reproductive rate of around 17. Do we have any better estimate of the reproductive rate?

A. The females lay between 2 to 3 egg masses which average around 30–35 eggs, so possibly close to 100 potential eggs per females.

Q. Do SLF carry wolbachia infections?

A. Answered live.

Q. Are egg masses that don’t hatch in the following year viable for a future year? What is the general hatch rate out of an egg mass?

A. Currently the information is that the egg masses are for a single year and do not extend into the following year.

Q. With the knowledge that egg masses aren’t laid within reach of traditional treatment (i.e., scraping or hand-held pressure sprayers), how can we change our treatment of egg masses during the winter? I heard “get creative” as a suggestion. Are there any specific ideas for reaching higher into trees?

A. Other than sprayers that can reach higher for treatment or in the case of NJ they were using extension poles to smash and scrape. I am in NJ using scraper poles and paint rollers!

Q. Some egg masses are “naked” without the putty-like covering. Any reasons for this occurrence? Diet or nutrition limitations of feeding females?

A. This is a good question and it is not entirely clear why this happens or in some cases it is only a partial covering like they ran out.

A. In response to above question. This is something we intend to investigate. There is a predator that denudes all of the wax off of SLF egg masses and we suspect this will cause desiccation and freezing of the eggs, but this needs to be tested. Naked egg masses (naturally not covered with wax) will be included.

Q. Does the dip in Bug Barrier efficacy line up with adult emergence/mating flight? (behavioral change from climbing to flying)?

A. Bug Barrier becomes less effective with 4th instars (can jump over it) and adults. Joe Francese from APHIS puts 3 layers of foam for 4th instars and adults. It’s better for 4ths but adults are still not caught at high numbers.

Q. What was the Facebook page called for the Birds Biting Bad Bugs?

A. Birds Biting Bad Bugs:

Q. Do nymphs hatch all at once or over an extended period of time (hatching synchrony in an egg mass)?

A. Eggs from an individual egg mass hatch within a day or two of each other, but different egg masses hatch at different times.

Q. Any further observations of gypsy moth parasitoids from SLF eggs?

A. Houping Liu of PA DCNR found a low percentage of SLF eggs parasitized by a gypsy moth parasitoid. This has been published. Occurrence, Seasonal Abundance, and Superparasitism of Ooencyrtus kuvanae (Hymenoptera: Encyrtidae) as an egg parasitoid of the spotted lanternfly (Lycorma delicatula) in North America. Forests. 10 (2): 79.

We could also do an intensive survey of other planthopper nymphs in China to see if any are parasitized by Dryinus sinicus.

Q. If searching for egg masses, and you find one, is there some type of rule to find the nearest neighbor egg mass?

A. Answered live.

Q. Was any phytotoxicity or bark staining observed on Ailanthus or red maple (or any other trees) when 5% oil was applied?

A. Answered live.

Q. Can you reiterate where Dr. Roush said we can find more info on these Beauveria studies?

A. The journal citation was Clifton et al. 2020 Environmental Entomology 49:854–864. Here’s a DOI link:

Q. Did oil treatments show better efficacy against eggs in the early spring months? Overwintering weathering creates openings within the putty coverings & allows better oil penetration?

A. Good question. Our studies in USDA had slightly better efficacy with spring applications possibly due to the reasons you presented. This was similar to what was observed in South Korea with egg mass treatments. But the closer the treatments were to hatch, they became less effective in South Korea.

Q. There is a special issue in Environmental Entomology (2020) on SLF with 12–15 papers (can’t remember exact number) in this collection. Lots of good info in this group of papers.

A. The link mentioned above is

Q. What about concerns regarding surface or ground water contamination with dinotefuran or its degradates? (Being that it is so water soluble.) Do you minimize that by avoiding applications on windy, rainy, etc. days?

A. This is still in development, but yes, environmental impacts or concerns need to be addressed with flight and spray parameters to avoid any potential impacts.

Q. Were forest areas open or close for aerial apps?

A. Answered live.

Q. Was canopy close or open for applications?

A. There was some variation across the plots from what I recall being reported. I would have to defer to the folks involved at Penn State on the description of the canopies. I know they also looked at host composition of the plots and size and dbh of trees.

Q. So knowing successful hatch rates becomes important to know here.

A. Yes. There is also a concern of course of how temperatures will affect hatch rates if SLF moves further south. Melody Keena will be talking about the effects of temperature later today.

Q. Would the weight impact the distance traveled?

A. Answered live.

Q. Joe any thoughts on malaise traps for SLF?

A. We tried a canopy malaise-type trap for Sirex years ago. It might be worth revisiting with SLF, but I’m not sure.

Q. Are there any significant concerns regarding bycatch for non-target insects with the circle traps?

A. We don’t see a lot of by-catch in the circle traps. The entry hole is pretty small (~2–3cm). We’ve seen some coleoptera, ants, flies, wasps and a few native planthoppers, but we predominantly catch SLF. As far as the jar traps, we did have one live mouse that decided to make a nest in the trap and we’ve seen a very small number of reptiles on BugBarrier.

So we’re seeing higher efficacy against SLF as well as minimal damage to friendlies—sounds like a far better alternative to sticky band traps.

Q. So the egg masses can last up to a year if you keep them at a certain temperature to prolong emergence?

A. Yes, you can keep them at low temps below which they would emerge/hatch. Sorry I can’t remember the exact temperature that the researchers are using. You do have to chisel off the egg masses with bark as the egg mass break apart otherwise. It is definitely an art. Plus it is somewhat destructive to the tree so trees like maples can be a challenge to collect from sometimes in terms of permission.

Q. Is there any indication of what alternate hosts could be for Anastatus? Do parasitoid wasps tend to parasitize within insect families, such as within fulgoridae?

A. Yes, I believe that is still coming up in Hannah’s presentation.

Q. At what point does the nymph die with dryinus, and do the nymphs die just from the eggs or do the wasps also eat them?

A. Answered live.

Q. Hi Tracy, what grape cultivar did you use?

A. Answered live.

Q. Is methyl bromide being phased out production?

A. Yes, it’s production and use in the US are being phased out with exceptions for critical uses as well as quarantine and pre-shipment.

Q. How did you measure die off on the trees vs. the petri dishes? Was there no movement of SLF to the dino treated trees from other areas?

A. Answered live.

Q. Has any work been done with flonicamid, pymetrozine or diamides for SLF management?

A. We have... they don’t work very well!

Q. Will SLF survive in the South?

A. The constant temperature data suggests there may be some high temperature limitations. We are doing the heat wave study to see if they can tolerate variable temperatures that include 35 and 40 C which are too high as constant temperatures. Gypsy moth starts seeing negative effects at 30 C and its spread has been limited in the south. SLF seems to have issues with 35 C and up which would make the limitation further south than is for possible for gypsy moth (about the Carolinas).

Q. Since Ailanthus tends to compete out other trees, what seedlings are being represented on the percentage maps?

A. Answered live.

Q. The photograph with the ring of a white fungal mat around the base of the trunk has been reported to be able to penetrate the bark & plug-up vascular tissues. Have tree deaths been observed with these infections?

A. Answered live.

Q. Should we expect more sooty mold growth in more humid areas?

A. Good question. The sooty mold grows well with warm temperatures and higher humidity, but precipitation can actually dilute and/or wash away sooty mold on the leaf surface.

Q. I see some similarity with inspecting trees for egg masses that Asian longhorn beetle surveys use—they also use tree climbers. Since we can’t easily cut down trees to inspect for egg masses, would tree climbers be a viable alternative?

A. Since TOH is a soft wood I would think it would be too dangerous to climb much like cottonwoods. Bucket truck would be safer.

Q. What size chemical strips are best for use in the circle jar traps (i.e., 1 inch by 1/2 inch) or a larger size?

A. We use the larger ones, but I think the smaller ones are fine. We’re going to be testing this year to see if we can drop them.

Q. What size/type/source methyl salicylate lure is best for the circle traps?

A. We use a 53mg/d bubble cap that we get from AlphaScents. I think that’s the same one that the PPQ Survey Supply buys as well.

Q. was there any evidence of cavitation (embolism) in xylem from tree cores taken from heavily fed upon plants?

A. Answered live.

Q. What about sampling by just putting the rollers in water filled containers, similar to nasal swabs?

A. Answered live.

Q. All pictures show sampling on the bark—is there any way to sample the foliage? would that have any benefit?

A. Answered live.

Q. How did you collect honeydew?

A. Answered live.

Q. What about taking leaf clippings for E-DNA? Would that work from tree to tree?

A. Answered live.

Q. Does rainfall help with distribution of the fungi?

A. Answered live.

Q. So kind of similar to Phytophthora, damp cool weather helps Beauveria?

A. Yes.

Q. Did you find any of the commercial Beauveria genotypes in your field collections?

A. Answered live.

Q. It would be interesting to see if these entomopathogens grow endophytically inside tree of heaven and other plants spotted lanternfly are feeding on. Do you have any plans to look into this at all?

A. Answered live.

Q. Given the uptick in wild activity follows egg laying timing (the next generation laid), do you think the “control timing” can be made to work sooner?

A. Answered live.

Q. Are you planning to track resistance to fungal infection in exposed populations of SLF?

A. Answered live.

Q. Is deformed wing virus for lanternfly occurring? One slide displayed lanternfly adults with deformities.

A. Answered live.

Q. Why no spread into Maine, New Hampshire and Vermont? Millions of people travel to Maine every year. Many come from PA, NY, NJ, etc.

A. This is likely due to the large effect human population density has on dispersal in our model. Stephanie will soon be showing New England might be not warm enough for them to complete development to the egg laying stage. This is of course barring evolutionary changes.

Working on “bottom-up” models that explicitly address transport likelihood based on trade flows, traffic flows etc., as well as incorporate climatic suitability, will probably give us more specific forecasts. We’re working on one that builds upon the model Stephanie just presented, adding spread through natural and human-assisted dispersal.

Q. Long distance artificial movement will likely occur during the next few years and will become more common as the infested area increases. How can modeling be adjusted to reflect this likelihood?

A. Yes, definitely! There are already instances of transport as far as California, so we should anticipate higher likelihoods of long-distance dispersal. One way to account for it (which we’re working on) is to model bottom-up long-distance transport through road/rail/plane. Nadège will soon mention some preliminary work on human-assisted transport.