A Northwoods Almanac for August 17 – 30, 2018 by John Bates
Aspen Blotch Miner
Several people have contacted me regarding diseased aspen trees (“popples”) in our area, something I’ve noticed as well. I’m not well-versed on tree diseases, so I usually refer folks to Linda Williams, the forest health specialist for the WDNR in Woodruff. Here is Linda’s response to one of the individuals who had contacted me: “The issue that you’re seeing is the defoliation from a tiny caterpillar called Aspen Blotch Miner. This tiny caterpillar lives inside the leaf (between the top and bottom layers of the leaf).
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| photo by Wendi Home |
“The damage that they do looks significant, [but] it is not cause for alarm because the damage doesn’t seem to have an impact on tree health overall. The reasons for this are 1) the trees have had all spring and early summer to produce food, so damage to the leaf now isn’t as bad as something that defoliates the trees early in the spring, and 2) aspen will often send out a new flush of leaves mid-way through the growing season and those leaves will typically not be infested by Aspen Blotch Miner. Since they don’t have any major health impacts on the tree I don’t usually recommend any control.
“We saw damage from this insect last year in Vilas and Oneida Counties as well as a number of counties to our east (for some counties like Marinette, this is the 4th year of damage). Since the adult is a moth, it can fly to new areas and lay eggs, so you may not have had much defoliation last year.”
Migration
Our insect-eating songbirds are migrating south, and our ruby-throated hummingbirds are tanking up for their flights, too. We like to think of these birds as “our” birds, but really, they spend only a few months here and far more time in their wintering habitats. I’m always saddened to see them going. I already miss song-filled dawns and their colorful flitting in the trees.
Even though our local hummers may be leaving soon, keep your feeders up into October for other hummers migrating through.
Monarchs Soon to Migrate
“The monarch is . . . one of the few butterflies in the world that is able to explode out of the tropics into the temperate zone which is the most complex migration of any insect, of any invertebrate in the whole world. It’s so birdlike” (Dr. Lincoln Brower, considered the leading authority on the biology of monarchs).
Here’s my best shot at a quick summary of the remarkable life cycle of monarchs (adapted from the University of Minnesota Monarch Lab):
1- The monarchs that spend the winter in the mountains of central Mexico migrate north beginning in March. These are the same monarchs that migrated last autumn to Mexico from regions throughout much of the U.S.
2- They stop and lay eggs in northern Mexico and the southern US from late March through April. Farther north, the last eggs are laid in late April or early May. These new monarchs become Generation 1. Since it is often cool when Generation 1 larvae are developing, it may take them up to 50 days or more to develop from eggs to adults.
3- Generation 1 adults emerge from late April to early June. They quickly mate and begin to lay eggs about four days after emerging! Still, they continue the journey north that their parents began, laying eggs along the way and begin to arrive in the northern US and southern Canada in late May. Eggs that become generation 2 may be laid as late as July in the north.
4- Monarchs that emerge from those eggs become Generation 2 and are the grandchildren of the previous overwintering monarchs. Those laid in the southern part of their range continue to migrate north. Generation 2 adults emerge in June and July, mate, and also lay eggs soon after emerging. Most of those that begin their lives in the south still move further north as adults to avoid the hot and dry weather. Those that emerge farther north may not move far.
5- Some of these newly emerged Generation 3 monarchs may appear early enough to produce yet another summer generation – Generation 4 – but many don’t. Generations 3 and 4 monarch eggs are laid throughout the northern part of their range in July and August. However, Generation 3 individuals that emerge late in August will undergo diapause (a period of suspended development) and migrate to Mexico. Monarchs in Generations 3 and 4 are the great- and great-great grandchildren of the overwintering monarchs.
6- These late emerging monarch will not reproduce right after they emerge. In response to decreasing temperatures and shortening daylengths at the end of the summer, their reproductive organs remain immature. Instead of mating and laying eggs, they spend their time drinking nectar and clustering together in nighttime roosts in preparation for their long journey south. This delayed maturity is called diapause. During September, October, and early November, migratory adults fly to overwintering sites in central Mexico, where they remain from November to March. In March, they will begin to journey north again.
White-lined Sphinx Moth
Numerous people have recently sent me photos of white-lined sphinx moths (Hyles lineata) nectaring on flowers in their gardens. Some folks understandably mistake these moths for hummingbirds as they hover at tubular flowers, sipping nectar with their long proboscis that unrolls like a party favor. They beat their wings very fast like a hummingbird, which makes them a blur to photograph, and they’re also able to hover in mid-air, again like a hummingbird. They’ve been clocked flying at speeds as high as 30 miles an hour.
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| photo by Howard Peitsch |
They’re especially attracted to scented and brightly colored flowers, and have been feeding in our flower gardens on our bright red Oswego tea (Monarda didyma) and its close relative, bee balm or wild bergamot (Monarda fistulosa). They’re also known to prefer cardinal flower, columbine, evening primrose, lilac, penstemon, petunia,and phlox. In the evening, they prefer white or pale-colored flowers which are easier to see in the dark because of their contrast with green foliage. The adults are primarily early evening to nocturnal fliers, but we’ve been seeing them frequently during the day.
The adult females lay their eggs on plants in the spring – host plants in the Midwest include apple, evening primrose, grape, purslane, tomato, and willow-weed. The caterpillars that hatch out are quite variable in color, though the typical Midwestern color morph is green (dark to lime green) with a series of black lengthwise stripes, along with yellow and orange or pink dots. All have a pointed horn at their back end that may be yellow or orange. The horn is harmless, so don’t be concerned that it’s a stinger. The caterpillars develop through 5 instars (molts), growing up to 3½ inches long, then burrow 1 to 4 inches into the ground to pupate, eventually emerging as adult sphinx moths.
The adults serve a role in pollination, and at all stages of growth they provide food for predators. These relatively common moths occur throughout most of North America, from southern Canada down to Central America, as well as in Eurasia and Africa.
American Cancer-root or Squawroot
On one of our old-growth hikes last week, we found a plant that can best be described as resembling a pine cone or cob of corn. Called American cancer-root or squawroot(Conopholis Americana – conos means ‘cone’ andpholos means ‘scale’), this very odd flowering plant has no chlorophyll, and thus doesn’t photosynthesize. Instead, itgrows on the roots of oak trees in our area and derives its nutrients from the tree.
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| photo by Mary Burns |
There’s no scientific evidence that it either prevents cancer or causes cancer. Instead, the parasitic roots cause the formation of large rounded knobs on the roots of the host tree, which is most likely the origin of name “cancer-root.” I can find nothing, however, on why it was once called “squawroot”.
It is not clear in the literature if the plant compromises the health of its host tree. It may instead exist in a stable parasite/host symbiosis with its much larger and longer lived host oak.
The plant is eaten by bear and deer, which then disperse the seeds in their scat.
Fungi Time
August and September are the peak months for mushrooms. During these months, one can walk a path without seeing a mushroom, and two days later walk the path again, and it will be loaded with mushrooms.
Mary and I continue to slowly learn our mushroom IDs. It’s an intellectual struggle, but such a fun one! Mary has an excellent eye for spotting them, and last week she found a comb tooth mushroom (Hericium ramosum or coralloides), a pure white fungi with myriad branches that look like snowflakes.
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| photo by Mary Burns |
It’s saprophytic, usually living off the decay of downed hardwoods, especially birch and maple. Apparently, it’s a delicious edible, but Mary and I rarely eat the mushrooms we find – we just don’t have enough confidence in our ID skills. Plus, some things are so pretty that they should just be left alone.
Celestial Events
Four planets are visible after dark this month. From west to east, they are Venus, Jupiter, Saturn, and Mars.
Today, 8/17, look for Jupiter five degrees below the waxing crescent moon. On 8/21, look for Saturn two degrees below the waxing gibbous moon.
August’s full moon occurs on 8/25 and 26. Called the “Corn” or the “Rice” moon among many names, the moon will be 100% illuminated on both 8/25 and 8/26.
We’re losing our evening light at a rapid pace – by 8/28, we’ll be down to 13.5 hours of daylight, with autumn equinox just over three weeks away.
Thought for the Week
“One of the greatest peculiarities of the past is that it shapes so very much of who we are – and yet in a very real sense it no longer exists save for the traces of it we carry in our memories. Without us to remember and reconstruct it, there would be no past. Much of growing up has to do with the expansion of our capacity to remember.” – William Cronen
Please share your outdoor sightings and thoughts: call 715-476-2828, e-mail at manitowish@centurytel.net, snail-mail at 4245N State Highway 47, Mercer, WI, or see my blog at www.manitowishriver.blogspot.com.
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