2023 SLF Summit Q and A - Day 1

Compiled by Jerrie Haines, Northeastern IPM Center

Dana Rhodes | danrhodes@pa.gov | Pennsylvania Department of Agriculture

Q. If an adult doesn’t survive does that mean the SLF can’t spread . . . that is end of line for that cohort of SLF?

A. If an adult lays an egg mass, then the SLF will continue to survive if the eggs hatch the next season. In PA all adults die, but the egg masses survive.

Nicole Szubart | nicole.szubart@usda.gov | USDA

Q. Based on the results of these two studies, do you think that conclusions support that the removal of Ailanthus would negatively impact the development of SLF across all life stages?

A. It would not significantly affect the development of SLF.

Tracy Leskey | tracy.leskey@usda.gov | USDA

Q. Being a “suitable host” means that the plant is at risk of mortality or merely reduced growth.

A. We did see some impacts from SLF feeding on non-bearing peach trees, but not on apple. It was an interesting finding.

Q. Based on your studies does this mean that SLF can’t reach reproductive adulthood without having Ailanthus to feed on? Another way to put this is if SLF can’t feed on Ailanthus are the able to lay eggs?

A. They are able to lay eggs. See Kelli Hoover’s work as well.

Q. Is there a reason that the population in Korea went down and why there is such a low number more recently?

A. They talked about a biocontrol agent being present. Anastatus orientalis, I think.

A. S. Korea has an established population of Anastatus orientalis egg parasitoids, which may be playing a role in reducing populations.

Q. I may be wrong, but it appears that peach also fruits earlier than apples, and may have a stronger sap flow sooner in the season.

A. Definitely an earlier phenology.

Flor Acevedo | fea5007@psu.edu | Penn State

Q. Based on your studies does this mean that SLF can’t reach reproductive adulthood without having Ailanthus to feed on? Another way to put this is if SLF can’t feed on Ailanthus are the able to lay eggs?

A. Yes, they do lay eggs without access to TOH.

Q. The images appear to show adults coming out of the third instar, not the fourth (which is red). Am I reading this incorrectly?

A. Definitely a fourth instar emerging from a third, not an adult.

Q. Flor, do you think the same SLF development you found on concord could be with other varieties.

A. Vitis vinifera cultivars seem to be more susceptible to SLF.

Q. Did you take into consideration favoritism of certain TOH and what reasoning for that is when doing research with SLF?

A. TOH is an invasive species from the same geographical range as SLF (Asia). TOH is considered SLF’s preferred host plant. SLF can develop without TOH, but its fitness is highly reduced. Also, in Pennsylvania we are recommending people to eliminate TOH as a management practice. These are reasons why TOH was included in the study. Thanks for your question!

Q. Was there a noticeable effect on grapevine fruiting from SLF feeding?

A. We did not look at fruiting. We shop the clusters as they developed. We wanted the plant to invest resources on producing leaves not fruits.

Laura Nixon | laura.nixon@usda.gov | USDA

Q. Has anyone considered studying its life stages on or near invasive bamboo? We have found egg masses near bamboo.

A. I don’t know of anyone looking at bamboo specifically, but I’ll keep my ears open for it!

Phil Lewis | phillip.a.lewis@usda.gov | USDA

Q. What concentration of golden oil is required to reduce hatch significantly? Cost of this product at that rate?

A. Egg mass spot treatments are put out at 1:1 with water. I’m not sure of the cost.

Q. How tall were the trees treated during this test? Did you have any issues getting coverage of GPSO in the taller trees?

A. For egg masses, these were spot treatments of individual masses, and we were not spraying down entire trees or limbs. For the nymphs these were small scale tests, and we did not put out broad scale applications.

Q. Do you think the degradation of egg masses is due to application? Like if the spray bottles just didn’t have a mist setting, so the spraying disturbed the egg masses.

A. Controls were treated with water and we never saw degradation from water. The GPSO definitely degraded the integrity of the masses. We soaked the masses, did not try to use high pressure to impact them with the sprays.

Q. Does golden oil prevent the sloughed eggs from hatching? Or could they still hatch off the tree?

A. Yes, we saw very little hatch from the eggs noted as degraded in the pictures. Some could have hatched but quality of pictures was not always clear.

Q. Is GPSO legal to use in Canada? stollerusa.com/products/all-products/row-crop/golden-pest-spray-oil/

A. Sold by Stoller, not sure if it is sold in Canada.

Q. What is the benefit of using the GPSO versus scraping the eggs? If scraping eggs, how important is it to squish the eggs as you scrape? If the eggs fall on the ground without being squished as you scrape, do they still hatch? Or if they are uncovered to they do not hatch?

A. Sometimes there are so many egg masses that scraping is laborious. I did look at scraping an egg mass right into a petri dish and I did get hatch from that, so it is important to squish all of them, as they can easily survive if just scraped off the surface.

Q. As far as initial attraction to the traps, could some of the trap materials be giving off cues to draw them in? such as scents or visual cues? Or are other lanternflies attracted by adults already there laying eggs? I ask this in a general sense because sometimes a given tree is loaded with eggs and yet a nearby tree has few eggs and yet appears to us as very similar in characteristics.

A. It was interesting that the horizontal oriented traps had very few egg masses laid in them, really no different than the background of what is generally laid in the area around the traps. So, not likely they are responding to the shingle material.

Q. For areas with no infestation history, do you recommend these aggregation periods for early detection surveys as well? i.e., if conducting visual surveys, focus on Ailanthus during early adult time windows to narrow down search area?

A. Also, I feel that the use of our egg mass traps would be very useful for monitoring areas with low or no known SLF populations, since it serves to concentrate their egg masses.

Q. Do you think the SLF were attracted to the surface texture of the lamp shade trap, or do you think they were attracted to the structural shape of the trap (as in, it provided cover)? or both?

A. The two key components were the substrate (roofing shingle) which they readily laid their eggs on, and the environment we were able to create with the two layers of “lampshade” that induced them to oviposit.

Q. To what extent is the transportation of wood log products a source of SLF introduction?

A. The original introduction was likely from stone products imported from Asia.

Morgan Dube | morgan.dube@agr.nh.gov

Q. Phil, when assessing the effectiveness of GPO, do the operculum’s of eggs from which nymphs have emerged always pop off, or do they sometimes stay on like a flap and lay back down over the hole? If the latter, does that make it more difficult to assess actual hatch rate by visual inspection?

A. I rear them in a lab and I have seen hundreds of hatches I’ve never once seen them lay back down the hinges always either fall off or stay vertical.

Q. The images appear to show adults coming out of the third instar, not the fourth (which is red). Am I reading this incorrectly?

A. It looks like we might not have been able to see the red patches but in theory they were there . . . ?

Q. Are states proactively removing TOH?

A. NH is doing some removal. Piera Siegert may speak about that coming up.

Emily Wallis | emily.wallis@usda.gov

Q. When did you deploy your lampshade traps (end of summer?), and how long have they been left out? Your work is super impressive Emily, thanks!

A. Hi Oliver, we set out the traps between 9/21 and 10/20 and they were left out until the end of December, early January. Thank you, our team worked hard to get to our final trap design!

Q. Did you get a chance to identify the fungus that was causing the “mold” on the egg masses? Will you be doing anything like this again? We would love to receive some egg masses killed by mold, as you saw. We’ve done some work with fungus on egg masses but did not prove that the fungus was killing the eggs. So, we are interested. Thank you, Ann Hajek.

A. Hi Ann, we did not identify the fungus, but I can ask around if anyone at the lab did. If you email me Emily.Wallis@usda.gov we can arrange for that to happen!

Houping Liu | hliu@pa.gov | PA Dept. of Conservation and Natural Resources

Q. When you spoke about working on the entire TOH how would you go about that if the branches were high up, with collecting samples and such.

A. We use visual survey (binoculars) from the ground for the entire tree. Sex ratio and reproductive maturation were only examined for adults on the 2 m trunk section. See link for details: www.hindawi.com/journals/psyche/2022/4775718/

Q. For areas with no infestation history, do you recommend these aggregation periods for early detection surveys as well? i.e., if conducting visual surveys, focus on Ailanthus during early adult time windows to narrow down search area?

A. No. For areas with no infestation history, early detection surveys should focus on egg masses, start from Ailanthus but extend to other substrates (trees, plants, nonliving objects) nearby.

Q. I think eDNA would be good for an un-infested area.

A. Agreed but it’s going to be hard to determine where to start.

Fransesc Gomez Marco | francegm@ucr.edu | Hoddle Lab

Q. Out of the native parasitoids what do you believe is the most promising in controlling SLF?

A. We do not have a strong candidate yet. My bet is on Anastatus genera but we are just starting. We will go to Chiricahuas to try to collect some native parasitoids this summer.

Scott Schirmer | scott.schirmer@illinois.gov | IL Department of Agriculture

Q. Has SLF been found around Chicago?

A. No SLF establishment has been found in Chicago/IL to date.

A. This is a good resource to see where there are IDs but no established populations: cornell.app.box.com/v/slf-distribution-map-detail

Samantha McDonald | samantha.mcdonald@usda.gov | USDA

Q. I have seen what would normally be an egg mass but when I go to scrape it, there are no eggs under the protective covering. Mainly seeing it this year and not in the past. Seems like a miss carry. Any ideas?

A. VA has been seeing this trend for a couple seasons now. Most of the time we are seeing it near uncovered eggs or old egg masses. Not sure if other states are seeing the same occurrences.

Melody Keena | melody.keena@usda.gov | US Forest Service

Q. Do you expect time to reproductive maturity (whether enough degree days/development can occur) in the northern reaches of SLF’s range will be a more common limiting factor than winter egg mass mortality?

A. It might be.

Eric Biddinger | ebiddinger@dnr.in.gov | Indiana Department of Natural Resources, Webinar Facilitator

Q. Airin — what is MISIN? Maybe I should know what it is, but I don’t.

A. www.misin.msu.edu

Julie Urban | jmu2@psu.edu | Penn State

Q. What about using more variable markers (genomic SNPS)?

A. I think that is a great idea. I am not a population genetics person (deep time phylogeneticist who had a postdoc who wanted to work on this back in 2014) but that would be what is needed.

Q. One of the questions I field from the public a lot is if scraping egg masses without treating them with alcohol or hand sanitizer is actually killing them. So, would your study suggest that disturbing them would help naturally occurring fungi infect the eggs?

A. I’ll let Daniel share his perspective too, but I don’t think that is necessarily the safest way to go. The fungus seems to be more hit or miss. And in my lab, we have had hatch from egg masses that have crumbled away to bits. And those didn’t get infected with fungus either.

A. I agree with Julie — it is a hit or miss. We have seen collected egg masses stay completely viable, and others colonized with a fungus. Our study hopes to understand this a bit more, especially with all of the variability with egg masses. (Daniel Taratut, tuj46631@temple.edu)

Amanda Roe | amanda.roe@NRCan-RNCan.gc.ca

Q. What about using more variable markers (genomic SNPS)?

A. Keeping good tissue collections over time would be really critical to this type of question, as well as addressing some of the questions around adaptation at the edges of their distribution.

Nael Kerzabi | Nkerzabi@pa.gov

Q. I don’t remember seeing as much tree of heaven in CA as in many eastern states but I wasn’t really looking for it either. Is TOH fairly common there?

A. Even in the mountain deserts of Arizona, I have seen TOH in settlements.

Christine Colley | christine.colley@dot.ny.gov | NYS DOT

Q. About removing TOH, PSU is encouraging doing so in grape areas in Erie County, PA, to try to slow down SLF population growth once it gets there.

A. This is important to note. NYSDOT is struggling with whether to remove TOH or not within our ROW. We have SO MUCH — especially on Long Island. The cost would be astronomical, and we aren’t sure if it would be worth the investment. But like PA, we were thinking about focusing on our ROW that fronts vineyards.

Q. Can the low number of adults detected in the nurseries be the result of egg masses not surviving the cold weather? How can you affirm that it is the result of egg masses removal?

A. Is it possible that the nurseries spray on their properties and that might be what kills the egg masses?

Rick Roush | rtr10@psu.edu | Penn State

Q. About removing TOH, PSU is encouraging doing so in grape areas in Erie County, PA, to try to slow down SLF population growth once it gets there. Does PA have an “official” document that makes that recommendation — to remove TOH around vineyards? It would be helpful to have that when discussing proposed actions with Exec. Mgmt.

A. Please send me your email to: Rick Roush, rtr10@psu.edu

Brian Ruether | brianfr@vt.edu | Virginia Tech

Q. Have you seen data on the estrogenic effects of lavender oil? www.nih.gov/news-events/news-releases/lavender-tea-tree-oils-may-cause-breast-growth-boys

A. I have not! Wild. Thanks for sharing.

Hannah Broadley | hannah.j.broadley@usda.gov | USDA

Q. Have parasitoids shown a preference for uncovered or covered egg masses?

A. Thanks for your question. To date we have no evidence that Anastatus wasps have a significant preference for uncovered or for covered egg masses. There is some evidence that they may be attracted to the chemical cues present in the egg mass covering.

A. Interesting, thank you!

Q. How long do you estimate it will take to test all the other noninvasive insects that could be affected by the parasitoid?

A. This is a very hard question. It of course depends on numerous factors. For example, the timing depends on how hard the non-target insects are to collect and rear. It depends on the life cycle of the parasitoid (i.e., how quickly they go through their life stages and when we can detect possible parasitism). It depends on what our initial findings show. For example, if no non-target attack is detected for highly related species, then it may not be necessary to include as many different disperse species. There are other factors, but these are some notable factors. And about timing, developing biological control methods can be quite fast (take just a few years) to taking much longer (more like 8 to 12 years). For D. sinicus, we plan to have some very informative results to share by the end of the season and much more comprehensive results by the end of the next growing season.

Daniel Taratut | tuj46631@temple.edu | PA Commonwealth University System

Q. Do we know if these fungal pathogens are as risky as a conventional insecticide for use by an applicator?

A. This will require further testing on SLF efficacy and subsequent plant pathogenicity. The species we are studying are already native fungi found in the soil.

Q. It would be interesting to see if diet alters to a noticeable extent, the ratios of elements in the egg mass.

A. Hi! Yes! Especially as SLF feed on such a variety of plants. Great point.

Q. And have you looked at Batkoa spp?

A. Hi! I haven’t been able to isolate Batkoa yet, but I know Ann Hajek’s Lab at Cornell is utilizing this general in efficacy trials against various SLF life stages!