@erininm had made this same map for 2016-2019. That thread is closed though.
I remade it and added all the years since then and tweaked some of the options. I also expanded the range to all of North America since it seems to have spread to Canada and there was a dead one found in Mexico as well.
So far for 2024 it seems like the range hasn’t actually expanded very much but the number of observations have since 2023. States seem to be doing a good job of being on the lookout for any expansions of its range
Edit: actually if we account for the growth in userbase in 2024, I wonder if there’s even been an expansion in population size
I wonder how much of a priority its containment will continue to be though if we now know that it doesn’t actually harm most trees (except for tree of heaven and maybe black walnut). And the hype around honeydew honey and its benefits to honeybees is growing
Cool, thanks for sharing! And wow that is a long URL.
I think we’re past the point of containment and should be / are focusing on control. One of the concerns is that the honeydew surrounding their host plants promotes the growth of mold that kills off the surrounding foliage by blocking photosynthesis. It can feel like it’s drizzling rain when you stand under a tree covered with them, and all that honeydew results in death of the plants below over time. For example, photo 2 of my observation here: https://www.inaturalist.org/observations/239475562 or the last two here: https://www.inaturalist.org/observations/239476316 and a close-up of the honeydew “glaze” that covers the ground here: https://www.inaturalist.org/observations/239476283 Most of the Ailanthus trees around here are still alive, but the plants under them are not so lucky.
They’re also a major concern for vineyards, so even if they’re not killing native trees, they’re still an economic problem.
Uh-oh, just what we need, one non-native insect benefiting from another non-native insect. :P I know some local beekeepers who say that Japanese Knotweed makes some really amazing honey too though. So I suppose invasives have their own way of giving back the economy. lol
Also, don’t forget, we had one SLF observation for 2015, right where it all began: https://www.inaturalist.org/observations/10912226
Actually sooty mold doesn’t infect plants. It can cover leaves and stress a plant but it’s very rare for a plant to actually die from the mold. We should also consider the fact that the mold is native and the honeydew is often beneficial to many native insects that feed on it.
Yes I agree they’re still an economic problem. In fact, I believe that’s the main problem they are. There’s not really ecological research that backs up the idea that they’re a major ecological problem.
I also share your apprehension about the non-native honeybee benefiting but they’re far from the only insect that benefits. Honeydew is consumed happily by a very wide variety of native insects. And we’re seeing more and more birds finally learn that these clumsy bugs are an easy food source (again, of course this will equally benefit non-native birds)
My honest feelings at this point are that the increase in pesticides we’ve seen in response to their spread may be protecting commercial interests but are coming at the cost of ecological interests. I think the pesticides are doing more harm to native ecosystems than the bugs are. Everyone agrees that they’re spread is inevitable and I agree we should do as much as we can to slow it down, but I am very concerned at the willingness to prioritize commercial interests over ecological ones.
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