Wednesday, August 05, 2020

Spotted Lanternfly in Princeton

Most people by now have heard of the spotted lanternfly, an insect native to China, Vietnam and parts of India that somehow showed up in eastern Pennsylvania in 2014. A leaf hopper with distinctive markings and colorful wings, it spread rapidly as it sucked the juices out of grape vines, orchards, and trees like Ailanthus, black walnut, maple and red oak.

Two years ago, local papers reported a sighting of spotted lanternfly in northeastern Princeton. Last year, the summer of 2019, a couple friends reported seeing it in Princeton--Mimi found a few in her backyard in western Princeton; Scott saw some in Herrontown Woods near the parking lot. 

For me, it didn't become real until I encountered this curiously tilted nymph on a butternut tree leaf near Veblen House in Herrontown Woods in early July. A Penn State Extension post describes the insect's colorful development from egg to nymph to the winged adults that emerge in late July.

For some reason, I had avoided writing about the spotted lanternfly. Maybe I was maxed out on the world's problems, and didn't really want to delve into the prospect of yet another introduced insect wreaking environmental havoc. 

Unlike the Emerald ash borer, which has gone largely unseen as it quietly kills every untreated ash tree in Princeton, 

the spotted lanternfly sounded poised to make a highly visible and messy invasion. The PA Dept. of Agriculture published a pdf with graphic photos showing mildewed foliage and tree trunks covered with the adult insects. And because plant juice is very dilute, the sucking insects need to move a lot of juice through their bodies to get the nutrition they need. That means that both nymphs and adults produce large amounts of "honeydew", which drops down from the trees and vines, and coats foliage on the ground with sugary liquid, promoting the growth of mold. Their egg cases look like mud, affixed to trees or cars or most anything. It sounded like our habitat restorations and garden beautifications would be reduced to a tattered, moldy mess.

Below are compiled some research and experiences with spotted lanternfly this past weekend at Herrontown Woods. 

Ailanthus--the Spotted Lanternfly's favorite food

Turns out that the spotted lanternfly has a strong preference for sucking the juices of Tree of Heaven (Ailanthus altissima). Native to China, Ailanthus is fairly common in Princeton and can be invasive, forming clones and sprouting aggressively from its roots if cut down. A stand of Ailanthus can be used for trapping the spotted lanternfly. Penn State extension offers tips for homeowners on this. 

At the Herrontown Woods botanical garden, next to the parking lot, we have an Ailanthus growing, and sure enough, some adult lanternflies were found clinging to its bark.

Looking up, the Ailanthus leaves appear to be getting eaten, though the lanternflies are said only to suck from the trunk and the stems, not the thinner tissue of the leaves themselves. 

In a sense, the preference for Ailanthus is good news. An invasive tree is being attacked by a newly introduced insect from a similar region of the world. But the tree is also helping the insect expand its numbers through the summer, and toxic compounds in Ailanthus, when ingested by the lanternfly, may confer some protection from predators.

The lanternfly's honeydew is causing sooty mold to grow on the plants underneath the tree.  The NJ Dept. of Agriculture info sheet reports that the sap dripping from "weeping wounds" on tree trunks can attract stinging insects. 

Probably the best thing to do is to take down the Ailanthus, using techniques described here.

More advice for homeowners

There's an enjoyable and clever article on various tactics on the MercerMe site. For instance, the adults are very quick to jump if you try to squash them. The article says their reflexes slow down with persistent efforts, however. Will test that next time. Another thorough read for homeowners is at this link, including a test to see if chickens would eat them. They didn't, but more research is needed.

Longterm prognosis

Will the spotted lanternfly prove to be a longterm calamity, like the Emerald ash borer, or fade into the background as a passing problem? Will it be a lasting plague for vineyards and apple orchards? An article reports that few lanternflies were seen this year in the area of Pennsylvania where it was first discovered five years prior.  Local Princeton arborist Bob Wells is quoted in the Town Topics as saying that though vineyards and apple growers have reason for concern, for homeowners the insect "won't be much of a threat at all." I inquired on a listserve that includes land managers in Pennsylvania who have had the insect around for several years now, and got mixed responses. One observed reduced numbers one year, then a rebound the next. 

It can be hard to know if you have spotted lanternfly in your trees. My friend LisaB, who lives near Herrontown Woods, had a couple black oaks fall near her property in late July, and was surprised to find numerous SLF nymphs on the leaves that until then had been elevated 70 feet above the ground. She had seen none in her yard up to that point. Her photos show the last nymph stage (red), 

and a beautifully captured example of what a newly formed adult looks like. Documented in past posts on this blog, insects like cicadasbutterflies, and apparently spotted lanternflies as well, must hang down as they unfurl their new wings. If the wings brush up against any obstruction, they can easily become misshapened. 

Update, Aug. 6: Walking through Quarry Park, closer to downtown, I noticed some Ailanthus trees near Spruce Circle,  looked up at the leaves above, and saw them there as well, a few scattered adults sucking juice from the rachis of the compound leaves. Will the spotted lanternfly be background or foreground, a quiet addition or serious pest? Time will tell. 

In the meantime, it looks like removing Ailanthus trees would be the most straightforward way to limit this new arrival's numbers and impact.

Reporting: I tried reporting the Herrontown Woods and Quarry Park sightings. The email address bounced, and the telephone number is always busy. It may be that the state doesn't want to hear about sightings in counties where the insect is already present, or maybe it's so widespread by now that the information isn't helpful.

Does milkweed kill lanternflies?

On the leaves of common milkweed growing near our Ailanthus tree, I found several lanternflies belly up or immobilized, leading to speculation that the insects sucked juices from the milkweed and died from the toxins therein. 

Sunday, August 02, 2020

Lisa's Salamander Rescue

This spring in late April, I received a surprising email from my friend LisaB who lives out next to Autumn Hill Reservation, across from Herrontown Woods. An amphibian had mistaken the water sitting on top of her swimming pool cover for a vernal pool, and laid a cluster of eggs there. My somewhat informed guess? Spotted salamander eggs. 

What to do with this unexpected gift? The salamander was not completely off-track in having laid its eggs in a puddle suspended over a swimming pool. Through uncanny luck, the swimming pool's owner happens to care deeply about the amphibians that inhabit the woods behind her house.

Lisa had contacted me back in March--March 15 to be exact--to report that the frogs in the neighborhood had been on the move the night before. "This was definitely Herrontown frog migration night," she reported. "Dozens on the road at 5:30a, all headed" towards Herrontown Woods to mate and lay eggs. "I only saw them in a relatively narrow band of ~a half mile, from the entry to Autumn Hill to the curve at Stone Hill Church. They were mostly moving in the dark early this morning--by 7am they were gone. Hope that protects them to some extent. Traffic picks up after 7." She suggested we organize next spring to serve as crossing guards for amphibians needing to cross Herrontown Road to get to their mating grounds, as is done elsewhere in the state.

On May 25, Lisa sent me a report on what she had decided to do with the salamander eggs, which otherwise would have been lost when the maintenance crew came to service the swimming pool. Since it's inappropriate to remove salamander eggs from a nature preserve, Lisa took this backyard gift as a rare opportunity to see salamander development up close.

"I put some in a deep vernal pool in Herrontown Woods and hung on to a few. They live outside in a tank so they get all the usual temperature variations, plus bonus mosquito larvae to eat. They seem to really like live blackworms, which I am now growing in my fridge (uh, don't tell my kid). I'd love to see one develop spots, which takes a few weeks after transformation. They already have puny little front legs!"

On June 24, another update:
"Salamander larvae are starting to transform! Losing their gills and showing their spots. Voracious carnivores!"

And on July 7, more detailed reports begin about the salamanders' metamorphosis, mixing affection with the close observation honed in her career as a scientist: "The two that transformed first flew the coop. For now I put lids on the tanks, so the next three to transform are still here. Some cool things I didn't know:"

1) "As they start to transform, their GILLS start to develop bright yellow spots just before they regress."

2) "Each one has a unique spot pattern that coalesces and intensifies as they transform, which makes them easy to tell apart. Not sure what nucleates the spots."

"This sequence of photos, taken two days apart, shows the development of spots on a transformed salamander."

"They become very shy once they transform. The larvae are just hanging out in the water column. I know they're about to transform when I look in the tank and I can't find them. The ones that have transformed are always burrowed under the moss. Interesting, for a stage with what looks like aposematic coloring ("don't eat me! I'm brightly colored and probably toxic!"). Probably they aren't actually toxic, and so the bright yellow spots pretty strongly select against anyone who is ever out in the open."

3) "The darkness of the larval stage seems influenced by substrate--ones raised on light rocks are lighter in color than ones raised in a pile of leaf litter. Not sure if it's a developmental camouflage or they're just dark because they're eating/covered in leaf gunk. "

"Man, do they eat a lot of blackworms! 1/8 lb so far."

Here are spots developing on a "new guy." Photos taken on days 1,2,3, 6, and 7.

By mid-July, thoughts turned to what to do with the salamanders once they've grown. "Technically I think I'm not supposed to release them, given there is some risk of introducing new pathogens into the local population (e.g., from the worms I feed them, which came from afar). Two did escape, though, so that ship may have sailed."

The Watershed Institute didn't have room. Salamanders apparently, and fortunately, given the potential danger to wild populations posed by poaching, don't make very good pets. They prefer to remain hidden, and can live up to 20 years. Many have toxins in their skin, and can easily absorb harmful oils and chemicals on our skin if we touch them. 

Finally, Lisa reached out to the Mercer County wildlife center, which then reached out to the senior biologist from the New Jersey Division of Fish and Wildlife Endangered and Nongame Species Program, who gave the following advice:

"From what I’ve read below I consider this to be a pretty low risk release and would recommend her to release them as near as she can to reasonable habitat by her property and best case would be to release them during the late morning when there’s some rain or release them an hour or so after sunset during a rain." 

One thing I've learned while putting this post together is that spotted salamanders (Ambystoma maculatum) have a longer incubation period than most species. Most vernal pools dry up once the trees leaf out. Only a few stay wet enough long enough to sustain the larvae until they metamorphose into juveniles.

Lisa sent a link describing how spotted salamander eggs incorporate algae into the body of the embryo. They become solar salamanders. The algae symbiotically provides energy and eats the salamander's waste. The algae fades away during the larval stage of the salamander.
Thanks to LisaB for all these photos and information. One more thing she shared speaks to why this was such a meaningful experience for her:
"I've been turning over stones looking for salamanders since I was a kid, and have seen hundreds of Eastern Redbacks. Once, when I was <10, one of the other kids found what I now know was probably a spotted salamander, and came running to tell the others (we thought they were lying about a salamander the size of a hotdog). That was the closest I've come to seeing one, despite the fact that they are all over here, until 40+ years later one decided to lay eggs on our pool cover."

Saturday, August 01, 2020

Mile-a-Minute Vine in Princeton

Each year I conduct a solo campaign to keep the highly invasive weed Mile-a-Minute out of Princeton. It's a prickly annual vine that grows each year from berries produced the year before. Knock it out before it produces berries, and eventually there will be no berries to sprout. Otherwise, the infestation will grow and birds will spread the berries across all of Princeton, to spring up in backyards and vex homeowners with its thorns and rampant growth.

I know of two infestations--one at the Princeton Battlefield, the other down off West Drive on the gravel road to Rogers Refuge. Yesterday, passing by Princeton Battlefield, I stopped to uproot what Mile-a-Minute I could find and leave it on the lawn to dry in the sun. Like most annual plants, it has whimpy roots and can easily be pulled, wearing a good pair of gloves.

Princeton Battlefield has a remarkable history, which makes it all the more remarkable how ahistoric the landscaping is. Non-native turf is surrounded by giant kudzu-like topiaries of non-native porcelainberry vine growing over the native dogwoods that were proudly planted for the 1976 bicentennial. There's little hint of what the Clark Farm looked like on that fateful day in January of 1777. The lack of botanical context doesn't fit with the people and era the Battlefield is meant to celebrate. Plants were important to George Washington and other leaders of his time. They were farmers. It's not coincidence that the United States Botanic Garden was built to stand next to the U.S. Capitol building. What grew upon the land mattered back then. They didn't mow the lawn and think their work done.

Seeing a landscape so invaded and out of balance, I sometimes imagine a hospital with no doctors or nurses, only custodians dedicated to keeping the place clean. The patients are on their own, unless a volunteer doctor happens by to treat some localized infection. That's the situation in the vast majority of our landscapes, cared for by custodians armed with raucous mowers and leaf blowers, oblivious to the complexities of nature and its needs. 

In the meantime, I pull the Mile-a-Minute, trim back some small portion of the porcelainberry vines so the dogwoods might live another year, and wonder at the world's disconnect with nature.

The two photos show 1) porcelainberry vines overwhelming a dogwood tree, and 2) another sea of porcelainberry in which only the similarly invasive Canada thistle can manage to lift its pink flowers above the swarm.

Wednesday, July 29, 2020

The Grass That Ate The King's Highway

There's a curious sight as you approach Montgomery from Princeton on Route 206. Something is eating the Kings Highway. 

That something is Phragmitis, most frequently encountered in its highly aggressive, non-indigenous form. In wetlands, it displaces even the tough native cattails. On the other side of town, in Rogers Refuge just below the Institute Woods, we've been working for years to keep it from taking over the marsh.

Spreading its tall tassels along freeway ditches, it dominates the New Jersey meadowlands and can be considered a worldwide weed. Its scientific name is as sprawling as its growth habit: Phragmites australis subsp. australis. The native version, less aggressive and now hard to find, is termed subspecies americanus.

One source describes the introduced variety as "a hardy species that can survive and proliferate in a wide range of environmental conditions." Sometimes it's planted intentionally, to treat wastewater or reduce soil erosion. Mostly, it plants itself, then expands relentlessly, oblivious even to normally intimidating barriers, like asphalt.

The common reed is a grass, like bamboo is a grass. Unlike bamboo, which lives for decades without flowering, Phragmitis blooms each year, combining abundant seed production with bamboo's powerful capacity to spread underground. That combination makes it a transformative force not only in nature but in human habitats as well. 

Tuesday, July 14, 2020

Redbud Leaffolders and Orchids--Herrontown Woods in July

While the woods seems to slumber, July brings another wave of flowers at the Herrontown Woods botanical garden and the Veblen House grounds. Whether the number of flowers constitutes a wave or a ripple, the photography that is standing in lieu of an actual nature walk during COVID times captures something of the feel of walking the pathways.

I have seldom seen Culvers Root growing in the wild, but it is a native with a beautiful form to its flowers. You can see the flowers beginning to open at the bottom of a spike, commencing a slow progression upward that serves the pollinators well.

The mountain mint donated to us is thriving, its strong minty flavor protecting it from the deer.

Shrubby St. Johns Wort blooms for a long stretch in the summer, living up to its latin name, Hypericum prolificum. The deer leave it alone as well.

We human deer are letting a few pokeweeds grow to maturity. It has an annual stem growing from a perennial root, and can become too numerous if left unchecked. A previous post mentions the intentional or unintentional use of its berries as a dye, and an interesting tree-like relative it has down in Argentina, called the ombu.

Not sure what this soporific bumble bee was doing on a velvety leaf of wooly mullein, a dramatic nonnative weed I associate with rail lines in the midwest, but which shows up here and there in Princeton.

The drought prompted the installation of a gutter and cistern next to the roof of the kiosk at the Herrontown Woods parking lot. One rain keeps us in water for weeks, as we walk around the gardens, giving new plantings a much needed drink.

Insects have been taking advantage of the many kinds of native plants we're growing--more than 100 species thus far. Meadow rue, for instance, is a seldom encountered wildflower in Princeton, discouraged by shade and the appetites of deer. But in the botanical garden, we can grow it in a protected, sunny setting. On May 10th this year, one of the tall meadow rues was found "donating" its foliage to caterpillars of the Meadow Rue Owlet moth, Calyptra canadensis. Thus a protected setting for seldom seen plants provides habitat for specialized insect species that otherwise have slim pickings in Princeton.

Another giving was discovered a couple days ago, on a redbud tree, some of whose leaves were folded up and turning brown.

Strands of silk tether the leaves, making protective chambers within the wrappings.

Opening one up, like a clamshell, reveals some energetic caterpillars busy chowing down and leaving dark trails of frass in their wake.

The speedy caterpillars are larvae of the leaf folder moth, with the provocative latin name Fascista cercerisella. Readers will be relieved to know that the insect is not a fascist. Originally, the word meant "bundle", as in a bundle of sticks, which can be extended to bundles of people who are part of a political movement. A fascicle means a bundle of leaves or flowers, while the Fascista caterpillar bundles itself up in a folded over leaf. The "cerce" in cercerisella likely comes from the insect's preference for laying its eggs on redbud trees, Cercis canadensis.

Up the trail at Veblen House, a patch of wineberries is going uneaten. As we've been clearing the invasive growth on the Veblen House grounds, a neighbor lamented that we had removed her favorite patch of wineberries, whose fruit are one of the small rewards for those who persevere through the muggy heat of a Princeton summer. Responding to neighborhood input, we've kept a few patches of wineberries.

Few will notice that the green fringed orchids at Veblen House are in full bloom. We've caged some to protect them from the deer. Below is an enchanting closeup of the flowers, giving the impression of wood sprites.

Wednesday, July 08, 2020

Princeton's Fuel Tank Raingarden Wannabe

Why would a plant lover be drawn to this desolate scene of concrete and asphalt? Because there's a raingarden behind that fence, or at least a raingarden wannabe, and that means I'm seeing not what is, which is pretty drab, but what could be, which is a dynamic, jubilant planting of native wildflowers, grasses and shrubs filling that skinny raingarden squeezed between the sidewalk and the town's fuel tank. The fuel tank was for awhile serving double duty, fueling town vehicles while its appearance fueled controversy in the neighborhood. A fine rain garden planting could go a long way towards healing the discontent, in my humble, totally plant-biased opinion.

The first good news is that the fresh layer of asphalt there appears to be appropriately tilted to shed its runoff towards the raingarden. What is a raingarden, after all, if the rain that falls on the surrounding topography doesn't flow towards it?

For some reason the raingarden hasn't been planted yet, so the plants have gone ahead and started planting themselves. It's looking a little sparse thus far, or you could say that the plants are social distancing.

Whenever I see plants trying to colonize bare dirt, I think of people who live in an emotionally impoverished situation. Back when I was in that predicament, I was drawn to places like this. Weeds trying to grow in parched ground were my friends and fellow travelers. Maybe that's why I can remember plant names when most people struggle, because the plants aren't just variations on green. They touch something deeper in me.

This late-flowering thoroughwort is a keeper--a native wildflower whose name is unlikely to flow smoothly from many tongues. It grows like a weed, and often in weedy places, like abandoned fields or roadsides, but can sometimes achieve great elegance of form when it becomes covered with plates of white flowers in late summer. It shows up early, but blooms late. Thus the name.

Here are the leaves of mugwort, which adds no color and spreads aggressively underground, taking over neglected raingardens over time. It's a force for monoculture and monotony that must be countered early and often.

Smaller scale weeds are clustered here, close to the ground, with dandelion on the lower right, a mock strawberry in the middle, and one 3-seeded mercury on the left. When I see one or two mock strawberries like this, I'm also seeing five years hence when it will have spread to coat the ground in an unattractive and inedible way. That increases the motivation to be proactive and pull it out now, before the task becomes overwhelming. This ability to imagine the future, learned in a garden, is directly translatable to global issues like climate change, where the job only becomes harder the longer one waits. 

Lots of homeowners puzzle over what to do with hundreds of oak seedlings in their yards, when everyone is telling them we need to plant more trees. Most tree species don't need help. They plant themselves, often in inconvenient places, like this raingarden.

Playing the editor, I'd say this nonnative red clover is a keeper as well, but pull the tall sweet clover at the other end of the raingarden. Sweet clover can be kind of pretty in a gangly way, but it is one of those midwestern and western weeds that appear to be expanding eastward, like teasel, Queen Anne's Lace, knapweed, and wooly mullein. Having lived in the midwest, I've seen how they can start to take over.

Leaping into the void in plants and action a couple months ago, I pushed some "live stakes" of buttonbush into the bottom of the raingarden. Despite the poor, hardened soil, they have sprouted. Here again, I'm seeing not so much the less than impressive seedling but instead the 8 foot high shrub it could become if it's allowed to get well established.

Just up Witherspoon Street, at the Princeton Recreation Dept. headquarters next to the community pool, is a demonstration of how gardens can look if there's someone knowledgeable taking care of them year after year. There's some serious tending going on here. Even the scarily aggressive variegated goutweed (whitish leaves on the left), which tends to take over gardens, is neatly contained in a discreet clump. These gardens owe their existence and beauty

to Vikki, whose job description in the Recreation Department probably has nothing to do with plants. From what I've seen over the years, it's clear that Vikki is one of the few people in town who is hard-wired to have a soft spot for public gardening, like Polly Burlingham with her hanging baskets downtown, and the various school gardeners, and like Dorothy Mullen was until she left our world earlier this year. I'd say that all it takes is love, and from that all things follow--vision, knowledge, persistence, strategic timing.

Maybe the sad, forsaken raingarden wannabe just a block away will somehow become loved ground. It's got "good bones"--sun, inputs of moisture. Good things could happen.

Tuesday, July 07, 2020

Proliferating Paradise

If you asked me what a utopian landscape might look like, it would be something like this. People talk more of dystopia than utopia these days, but this enclave stirred memories of utopian dreamers who were more common a half century ago. This is not a utopia filled with fantastical gizmology, but a more basic collecting of solar energy by plants and people to fill our needs for comfort, food and beauty. Though a deep forest would be somewhere nearby, houses would be producers, not just consumers, their roofs shaded by solar panels sending renewable electrons out into the neighborhood grid. And their front yards would be producers as well, of a joyous mix of wildflowers and vegetables.

Wild plants would mingle with domestic, and people would be a gentle mix of wild and domesticated natures as well. On this particular day, a neighbor was harvesting cucumbers and tomatoes while we plant lovers were inspecting the leaves of a curious plant grown from seeds we had collected from a wild remnant on the outskirts of town. We continue to be stumped. It's some sort of Silphium, not quite cup plant, not quite rosinweed. Genius nature has taken our breath and turned its carbon into yet another surprise.

The garden is largely the work of my friend Perry in Durham, NC, who began gardening in his own yard, then extended his work into his grateful neighbor's. Other neighbors on the block have picked up on the theme, getting acquainted with plants one at a time, until their lawns too have been displaced by something much more interesting and productive. It's a miniature experiment in proliferating paradise.

Perhaps paradise is too strong a word, being associated more with leisure than production, more with a tropical beach and soft sea breezes than an urban front yard. This is a plant-based, pandemic-borne, home-centered paradise.

I'm in Durham partly to see a close friend, but also to work on my house there, a 1919 house surrounded by towering oaks, but with a big lawn drenched with sunlight and potential to grow all kinds of interesting things. Being a long-distance gardener is even more challenging than being a long-distance landlord, particularly during a pandemic, but last fall, we started by planting seeds of local wildflowers and grasses around stakes in a part of the lawn where the soil had been freed of Bermuda grass. Perry didn't get my hopes up, sending periodic reports this spring of copious amounts of chickweed and weedy cranesbill filling the void in the lawn. It was a great surprise then to finally show up and find an enthusiastic crowd of intended plants around each stake, enough to populate a much larger portion of the lawn.

This is an unorthodox way of proliferating prairie. I used a similar technique at the botanical garden at Herrontown Woods in Princeton, where toddlers and their moms planted wildflowers in staked pods like this--mini-nurseries of clustered plants that were transplanted the next year to begin filling the whole forest opening. As the transplants produce seeds, they expand the overall planting still further.

Perry's been using incrementalism in a Durham nature preserve as well. At 17 Acre Wood, the first urban preserve I helped create in Durham 20 years ago, Perry and I checked out the hazelnut crop in a floodplain he has been working to shift towards native species.

One of the toughest spots was clogged with climbing euonymus, english ivy and periwinkle. Trees tend to be native, the understory not, but Perry is shifting the balance. It's hard to grow much in deep shade where water stands for much of the winter, but where the invasives have been removed, elderberry and jewelweed have bounced back, and a patch of lizard's tail has appeared.

The work is partly ecological, partly aesthetic, partly public safety, since removing invasive shrubs and vines improves vistas and sightlines along a public trail. This West Ellerbe Creek Trail, which follows the creek through the preserve, is also a story of incrementalism. It was a big hit with neighbors when it was built by the city in 2001, but would not have been built at all if not for the small steps that preceded it. A county government grant had helped our nonprofit create a nature preserve along the creek. Then the city, seeing we had created a destination, built the creekside bikepath to reach it. The result was a way for neighbors to take a nature walk in their own urban neighborhood.

To shift the world towards paradise, we really don't need new ideas, only people and organizations and governments doing what they each do best, combining incremental action with caring about the world and what we'll pass to future generations.