Dateline: September 7, 2012*
There’s an errant killer on the loose in Florida and other southeastern states. The ambrosia beetle likely arrived on packing materials from Taiwan, Japan or India, their native lands. First discovered in Georgia in 2002, these beetles carry a fungal disease known as Laurel Wilt and it is rapidly spreading.
I had heard about laurel wilt several years ago and didn’t give it much thought since it was far north of my county in Central Florida. Then, in 2009, I started to notice on my own street globs of brown, dying trees within the wooded areas. These are our beloved Redbay (Persea borbonia) trees. I had a small sapling that some bird had planted in my back yard and it seemed to be doing quite well. Then, it died a quick death. I called Forest Services and they came and took the sapling, but there was no conclusive proof that it was laurel wilt that killed my particular tree. However, the Forest Ranger did report that the trees in our wooded areas were victims of this disease that has no cure.
Not only is this invasive critter killing off our trees, there is also the potential that the Palamedes Swallowtail Butterfly (Papilio palamedes) could become extinct since the Redbay is the only host plant for this butterfly. Two other butterflies can use the Redbay as a host, the Spicebush Swallowtail (P. troilus) and Schaus’ Swallowtail (P. aristodemus), but both of these species have additional plants that can serve as hosts so the loss of the Redbay isn’t as threatening to them.
I was thrilled recently when a Facebook friend correctly identified a mating pair of butterflies that I identified as Black Swallowtails as Palamedes. Hope springs eternal. I have noticed a few Redbay saplings appearing along the fence line planted by resting birds that, after feasting on the Redbay berries, expel the seeds well “fertilized”. The scent of the leaves when crushed between my fingers is heavenly and proof positive that it is a Redbay or Swamp Bay.
In checking a young sapling recently, I was rewarded with the siting of an early instar palamedes butterfly caterpillar. He was munching away and will hopefully grow big and strong, build his chrysalis and emerge as a wonderful reproducing adult.
There is some hope based on studies of the recovery of Redbay (pdf dated December 2009):
“While the presence of redbay regeneration and the occasional discovery of live, larger-diameter saplings in the aftermath of a laurel wilt epidemic suggest that redbay will not go extinct, populations of mature redbay are nonetheless being dramatically reduced.”
The loss of Redbay also affects a number of our fauna since the berries are a food source for several different songbirds, wild turkeys, quail and black bears. Deer browse the leaves. It is the only known host of the redbay psyllid (Trioza magnoliae) a type of insect gall that is host to a type of wasp and a type of midge and also serves as a bird food source. You can see where devastation trickles down the food chain.
What the long-term affect of laurel wilt and the loss of mature redbays will have on the Palamedes remains to be seen. I’m just glad that some are still making a home at my place. They certainly are a majestic butterfly and it would be a terrible tragedy to lose them.
To help prevent the spread of the beetle that causes laurel wilt and other equally devastating invasive pests, DON’T MOVE FIREWOOD for camping or transport it for home use. What seem to be simple actions can have terrible affects on our native plants and those that rely on them for their existence.
Update March 2017:
Since initially publishing this article I have MANY saplings of swamp and/or redbay trees gracing my property and find eggs pretty regularly. Just this week I spotted a Palamedes Butterfly laying eggs on a Swamp Bay Tree (Persea palustris) out front.
Of course, now all hands are on deck to find a cure because of the potential harm to the Florida Avocado industry (note that Persea americana is an introduced species to Florida). Recent reports seem to have some potential good news in that area: “Repellant could keep dangerous beetles away from avocado trees”.
To me it is annoying that the efforts to rein in this invasive only proportionally increased when it was determined that a “cash crop” could be affected. Sad that the same value isn’t place on our native plants or native fauna. What does that say about our species?
* This is an update of a tale was originally published by Loret T. Setters on September 7, 2012 at the defunct national blog beautifulwildlifegarden[dot]com. Click the date to view reader comments.