Paul Hetzler is the horticulture and natural resources educator at Cornell Cooperative Extension of St. Lawrence County. A naturalist, arborist and writer, this Paul Smiths graduate happily shares his land with his children and other wild things. He welcomes questions at firstname.lastname@example.org.
What’s round to oval-shaped, mostly orange, and is a common sight leading up to Halloween? Everyone knows the answer to that: Harmonia axyridis, obviously. Better known as the multicolored Asian lady beetle, this insect is no treat when it masses by the hundreds on, and inside, homes in the fall.
Lady beetles, or lady bugs, are the darlings of small children everywhere. There are a number of native lady beetle species, which tend to be more reddish than orange, and they aren’t known to be nuisances in homes. Multicolored Asian lady beetles, however, are not as polite.
First brought to the U.S. in 1916 to control pests on pecan trees and other crops, the multicolored Asian lady beetle didn’t turn into an ogre until the mid-1990s.
Actually there’s evidence to suggest that the current population is a new strain accidentally released at the Port of New Orleans around 1993. Whatever their origin, they’re back in season each fall along with corn shocks and Jack-o’-lanterns.
Lady beetles don’t carry disease, damage structures, suck blood or sting, and they eat harmful garden pests like aphids.
However, they stain surfaces, give off a foul odor when disturbed and will even pinch one’s skin on occasion. It’s their sheer numbers, though, swarming a sunny exterior wall, massed in a corner of the garage or coating the inside of a picture window, which unnerve and irritate so many people. They are most active on mild days, and may reawaken during any warm spell, even into December.
The good news is that managing lady beetles will cut your heating bill. They’re looking for someplace warm to spend the winter and if a draft can get in, they can too.
Take some time to caulk around windows, vents and places where cable or other utilities come through the wall. Be sure to seal between the foundation and sill. Ensure that door sweeps and thresholds are tight, and check for cracked seals around garage doors. Install screens on attic vents and inspect all window screens.
If the beetles are already indoors, don’t swat or crush them or they’ll release a smelly and staining yellow defense fluid from their joints (creepy, I know). For a variety of reasons including the lady bugs’ habit of seeking inaccessible areas, indoor pesticide use is ineffective, and is strongly discouraged. Instead, use a broom and dustpan or a vacuum cleaner. Try using a knee-high nylon stocking inserted into the hose and secured with a rubber band as a reusable “mini-bag.” Just remember to empty it as soon as the vacuum is turned off. You can also make a black light trap—instructions can be found at: http://www.ars.usda.gov/is/pr/2001/010130.htm
This fall, I think researchers should try decorating giant pumpkins to look like multicolored Asian lady beetles to see if it will frighten the actual pests away.
Hopefully it won’t attract a mate of similar size. If you see a 100-pound multicolored Asian lady beetle on Halloween, please don’t swat it.
Paul Hetzler is a natural resource and horticultural educator with Cornell Cooperative Extension of St. Lawrence County
A nonfiction essay about damsels and dragons sounds like a contradiction in terms, or at the very least like a stale gender stereotype. But dragons are real. Damsels, while appropriately slender and elegant, and garbed in bright colors, are not the shrinking violets of fairy tales. They are every inch the airborne flesh-eaters that their chunky dragon cousins are.
If you’re out on a mild September day you may see large numbers of dragonflies and damselflies—shiny red, green or blue jewels—darting about. It’s a treat to watch them snap up insects and, more impressively, mate in mid-air.
Dragonflies and damselflies are carnivorous insects in the order Odonata. Dragonflies are in the sub-order Anisoptera, a term meaning not (an) the same (iso) wings (ptera). Their front pair of wings are longer than hind pair, which is one way to tell them from damselflies, which are in the sub-order Zygoptera in case you were wondering. There are an estimated 6,000 Odonata species in the world, nearly 200 of which have been identified in New York State.
Dragonflies, powerful fliers, can be so large they can look like a bird at first glance. When resting they keep their wings outstretched; a line of them basking on a log seem like small planes waiting to take off. I’ve been told it’s good luck if one lands on you. Probably the “luck” is that they repel deer and black flies.
Damselflies are much more slender than dragonflies. In damsel-like fashion, they fold their wings primly along their bodies And while many dragons are colorful, damsels outshine them with bright, iridescent “gowns.” Damselflies are sometimes called darning needles, and even the official literature lists such damselfly names as “variable dancer” and other descriptive titles.
Both kinds of insects are beneficial in that they eat plenty of black flies, deer flies, mosquitoes and other biting insects. Not surprisingly, they breed in the same habitats as their prey. Damsels and dragons lay their eggs right in the water or on vegetation along streams, rivers or ponds.
The nymphs (immature stages) are monster-like with little resemblance to adults. You can get a sense of what their choppers look like if you watch the movie Alien. Seriously, when magnified you can see their primary jaws (actually labia, but they act like jaws) open to reveal a second or even third set of hinged jaws (palps, technically). Depending on the species, nymphs get pretty big—the family Tanytarsidae produce juveniles the width of your hand.
Damsels and dragons spend most of their lives—between one and three years—underwater. Even as youngsters they put a dent in the pest population, gobbling soft grub-like larvae of deer flies and horse flies from the mud and munching mosquito larvae near the surface. They shed their skins, or molt, as many as twelve times as they mature.
Nymphs don’t pupate, but when full-grown they crawl from the water, anchor their toenails (tarsal claws) into the nearest tree stump or boat dock, and “unzip” their skin along their backs. Outdoing any science-fiction film, a graceful dragon or damsel emerges from its monster-skin.
After drying its new wings in the sun for a while, these killing machines fly off to eat pests, and of course to mate in a precise and complex ritual. This choreography involves the male passing a sperm packet from his primary genitalia at the end of his tail to a secondary set mid-body, from which the female retrieves it and inseminates herself. All while hitched end-to-end in a “wheel” and engaged in aerobatics. In some species the pair flies in tandem during egg-laying as well.
I hope you get to enjoy a few “Indian summer” days this autumn, and that you get to see dragons and damsels dancing amidst falling leaves.
Paul Hetzler is a natural resource and horticultural educator with Cornell Cooperative Extension of St. Lawrence County
If trees held a race to see which would be among the first to have their leaves turn color, the winners would be losers. Premature leaf color change is a reliable indicator of failing health, and the worse a tree’s condition, the sooner it begins to turn.
Precious few places in the world have a fall color show like ours, and the display that northern hardwoods produce each autumn never fails to fill me with awe and appreciation. But when it starts in July, as was the case again this year on some roadside maples, I know those trees aren’t long for this world. In early August even some forest hardwoods growing on thin rocky soils began to show color, which is also unusual.
The summer of 2012 is ancient history to some, but to trees it was practically yesterday.
In 2012 soil moisture dropped to record low levels, partly due to scant rainfall, but also because of low humidity, high temperatures, a very high UV index, and frequent and persistent winds. In such conditions, tree roots actually die back, beginning with the fine absorbing roots a few inches below the surface.
Most people, myself included, are surprised when they first hear that ninety percent of tree roots reside in the top ten inches of soil, and that very few roots penetrate beyond eighteen inches deep. Knowing this, it’s easy to understand how tree roots can run out of moisture in a drought.
A sort of Catch-22 situation happens as a result of root dieback. All the starches stored in the affected portions of the root system root are lost, so the tree has less energy the following year. But that’s when it needs extra energy to re-grow its roots. And because its roots are compromised, the tree can’t get adequate water and nutrients.
Dr. George Hudler, recently retired from the Plant Pathology Department at Cornell, says it takes a healthy tree about three years to recover from a significant drought. But what about trees whose health was less than stellar to begin with? Most, though not all, of the leaf color change I observed in late July was on older trees on roadsides. Those are subject to road salt, root zone restriction, reflected heat from pavement, and in many cases turf grass, which gobbles up all but the heaviest rains. It’s no shock that these are the ones that turn color first, but it was jarring to see it in July.
Understanding the significance of early color can be distressing, but it’s also an opportunity to gauge how the trees around your home and in your community are doing. Trees that have almost completely turned color by late August are probably in irreversible decline, and it’s time to consider their removal and replacement in the next few years.
Color change of twenty percent or less indicates moderate decline but severe stress. Watering the root zone about an inch per week over the next few years may help keep them around longer. Mulching the root zone (twice the branch length) two to four inches deep in lieu of grass will also help.
Quite frequently, poor planting results in a tree that should live for a hundred or more years dying after 20 or 30 years. It seems hard to believe, but the sudden decline and death of a 25-year old hard maple is often due to bad planting practices like failing to remove burlap and wire cages, planting too deeply or making an inadequate planting hole. These things lead to poorly formed root systems that develop girdling roots and other problems years later.
If a branch or section of a tree has turned while the rest is green, probably one or more major root flares have been damaged, either mechanically or by disease (of course one often follows the other).
Let’s do what we can to make our trees come in last in the leaf-change competition so we can enjoy fall’s colors without fretting that they mean trouble.
Paul Hetzler is a natural resource and horticultural educator with Cornell Cooperative Extension of St. Lawrence County
Being an arborist, I’m of course very mindful of complexion. Things like bruises and blemishes catch my eye, in addition to scabs, cuts, and even those out-of-place whiskers that appear out of nowhere. It sounds like a description of my aging skin, but I’m talking about blotches, warts and cuts that accumulate on tree leaves over the summer.
I suppose if we had to stand outside day and night all season, our skin would develop issues too. Those who work or play much outdoors need to be concerned about skin spots that suddenly show up. With tree leaves, that’s not the case—even the ugliest “skin” condition is generally no cause for concern.
One of the more alarming leaf disorders is called tar spot, whose symptoms are black blobs that often show up in late summer or early fall. Tar spot affects Norway, silver, red and sugar maples, in order of severity. The spots, which really do look like drips of roofing tar, seem to appear overnight, and sometimes cover much of the leaf. While it may look like a serious affliction, it’s really just a cosmetic issue (meaning if you’re good with cosmetics you can probably make your tree look pretty again).
Unlike the tar sands of northern Alberta in Canada, though, tar spots can’t be processed into crude oil. As disappointing as that may be, at least tar spot is not a problem. Spots are caused by several different species of fungi in the genus Rhytisma, which I mention because some of you play Scrabble.
If your tree’s leaves have sprouted tiny spindle-shaped structures that make it appear that the leaves need a shave, don’t worry. These are tiny galls, formed when a minute arachnid called an eriophyid (go for a triple score on that word) mite laid an egg, along with a dose of a plant hormone which directed the leaf to grow a little home for her young one.
Depending on the species of mite, these galls can be green, yellow, red or pink. Some are squat and thick, resembling a wart, but they are all completely harmless. Good thing, too, because galls shield the mites from anything you could spray on them anyway.
Believe it or not, scabs are caused by a disease called scab. I think it was late on a Friday when scab and tar spot were named, probably by a new intern who was later reprimanded for “making sense.” It affects apple, crabapple, hawthorn, juneberry and other trees in the rose family. Scab causes affected leaves to drop early, and is much worse in wet seasons when it can defoliate a tree by mid-summer.
It’s a serious problem for orchardists because it causes scab-like blemishes on fruit in addition to weakening the tree, so they routinely spray fungicides beginning at bud break. Other ways of managing scab include proper pruning, increasing air flow and access to sun, and buying scab-resistant varieties.
High winds, especially early-season events, can tatter leaves, a condition called “leaf tatter.” (Same intern, don’t you think?) Japanese beetles, caterpillars, sawflies and other insects chew on leaves over the summer, while leaf-cutter bees remove perfectly scribed circles. All in all, many trees look bedraggled by September. Should you be worried?
Here’s a secret: by late summer, trees don’t “need” their leaves any more. While this is true, it’s akin to saying you don’t need another five bucks at the end of the year. It would be nice, but it’s not going to change the big picture.
A deciduous tree expends a huge amount of energy investing in new leaves each spring, and its leaves have to make enough sugar from sunlight to “repay” the tree, plus a little extra for rainy days. By early August, trees have recouped their investment along with a pile of interest.
Late-season disorders are superficial and no cause for concern. But if you’re embarrassed by your tree’s appearance come late summer, you can always try cosmetics.
While most plants respond to late summer’s shorter days by starting to wind down their business for the season, goldenrod is a “short-day” plant, the kind that is stimulated to bloom by waning day length. It’s a perennial in the aster family, and is widespread across North America. We have something on the order of 130 species of goldenrod in the genus Solidago.
As one of the most abundant blooms of autumn, this native wildflower is for many insects, including numerous bee species, a vital source of nectar as well as of nutritious pollen. Unfortunately, this latter item has given goldenrod a black eye among many allergy sufferers.
Goldenrod’s showy yellow flowers are in full view along roadsides and in meadows and pastures just about the time fall hay fever season usually kicks in. So it’s understandable that goldenrod has been blamed for the red itchy eyes, sinus congestion, sneezing, and general histamine-soaked misery that some folks experience this time of year. But it turns out that goldenrod pollen is innocent of all charges.
Goldenrod can’t be guilty because its pollen is quite heavy. That’s a relative term, I suppose, since it’s light enough that bees manage to carry a great deal of it away. But in the pollen realm it’s heavy—and also very sticky—and it doesn’t blow far from the plant. It’s not that goldenrod pollen is incapable of eliciting an allergic response, it’s just that to do so, one would have to literally stick its pollen in one’s nose and snuff it up.
Not only is goldenrod guiltless of allergic assault, it has been used as an alternate source of rubber. Henry Ford was intrigued by goldenrod, and reportedly produced some tires made from the plant. Interest in goldenrod was revived during World War II. Goldenrod is also used in herbal medicine to help treat kidney stones, sore throats and toothaches.
So who’s to blame for the spike in late summer allergies? Surprisingly, the culprit is goldenrod’s cousin, ragweed, although it doesn’t behave at all like its golden relative (I suspect we all have a relative or two like this in our family tree). Ragweed, a native plant, is also in the aster family, but unlike goldenrod it churns out loads of very light pollen.
Just how light is it? Ragweed pollen can remain airborne for several days, and significant quantities have been found as far as 400 miles out to sea. And a single ragweed plant can produce a billion pollen grains to fly on the breeze and make you sneeze. Yep, this is the stuff that stuffs you up.
One reason we don’t suspect ragweed is that its blossoms are dull green and look nothing like a typical flower. It’s as if they’re trying not to attract attention. You can almost imagine them thinking, “heh, heh—let goldenrod take the rap.” The reason ragweed is inconspicuous is that it’s wind pollinated and has no need to “advertise” with bright colors and sweet nectar to attract pollinators.
Most ragweed species—there are about 50 of them—are annual, and come back from the copious seeds produced each fall. Ragweed will keep billowing allergens until the first hard frost, so let’s hope it’s not too much of an extended season this year. And let’s try to spread the word about goldenrod to spare it any further false accusations.
In recent days our North Country pharmacy has come into its own, really blossomed. Just to clarify, that’s not a financial report, it’s a botanical one. I have no idea how the drugstore business is faring, but a couple of our most storied medicinal herbs are flowering right now, and they’re a sight to behold.
The “pharmaceutical” plants are purple-flowering Joe-Pye weed, the doctor, and the nurse, boneset, sporting a crisp white cap. One of the reasons they’re a visual treat is that they often grow in vast swaths in poorly drained soils and near the edges of wetlands. Sometimes they co-mingle, and other times you’ll drive past an undulating wave of pale purple Joe-Pye weed, followed by one of bright white boneset. I suggest doing an image search of these plants so you’ll know what to look for.
Tradition has it that Joe Pye was a Native American who used this plant to treat New Englanders for typhus. Joe-Pye weed, Eupatorium purpureum, was recognized by the medical community as a bona-fide drug in the 1800s. Among herbalists it is still well respected for its effectiveness. Its roots are used to treat a number of ailments, especially kidney and bladder stones, and for this reason some know it as gravel root.
“Nurse” boneset is a native plant that is closely related to Joe-Pye weed, and it is no less important as a medicinal herb. Though never sanctioned as a legitimate drug, boneset, which I always think of as Eupatorium perfoliatum (true story, sadly) was reportedly used widely in the 18th and 19th centuries. It was taken to reduce fever and congestion, and even today some people drink tea made from its leaves when they have a cold or the flu.
Valerian is a European immigrant which can be found in the same habitat as Joe-Pye weed and boneset. It’s easily recognized by its bright white flower clusters as well as by its sweet, sometimes cloying, fragrance. Unfortunately it has just finished flowering in most places, so it’s less conspicuous than Dr. Joe-Pye and Nurse Boneset.
Valerian root is a common ingredient in herbal supplements intended to help relieve anxiety and sleeplessness, and has been used throughout Europe and Asia for at least a thousand years. It’s seldom sold as a bulk herb, though, because of its smell. Some compare its odor to stale perspiration, but I think that’s an unfair claim. It’s much worse than that. Valerian is very powerful, and should be used with caution, and never on a long-term basis.
While medicinal herbs can be beneficial, it’s essential to check with your doctor before taking any, and to only use them under the supervision of an experienced herbalist. Medicinal plants are exactly that, medicine, some much stronger than others. They have the potential to react with prescription drugs, and in rare cases can aggravate conditions such as high blood pressure and glaucoma.
Whether or not you ever make use of these medicinal plants, they’re putting on a show right now, and I hope you enjoy the performance.
What do you call a dairy farmer who spends decades improving the genetics of a herd, then abruptly sells all the best animals to start a new herd from scraggly, unproven stock? Crazy, perhaps, or foolish at the very least (or maybe someone with gambling debts). Under normal circumstances, no livestock farmer culls their best animals to start over with random ones.
Yet it’s common for woodlot owners to sell all the large, well-formed trees during a timber sale and leave nothing but small and defective trees to regenerate the next forest. OK, so my metaphor isn’t perfect—nobody shows up with a tank of liquid nitrogen to help with your tree breeding program—but it’s a reasonable comparison in a lot of ways.
Genetic variation in trees works just like it does in other organisms. If you take a thousand seedlings, some are going to have a slight genetic advantage.
Maybe they are more efficient at photosynthesis, or they’re less apt to develop weak (narrow) branch attachments that are prone to breakage. When an unusually straight, fast-growing tree rises head and shoulders above its peers, it’s generally more than mere chance—that tree probably has something the others don’t, and that’s the one you want seeding the next forest.
The multigenerational process of choosing superior genetics in trees is called silviculture. Ideally a forester marks defective trees to cull for firewood, and marks some of the mature trees for harvest. She or he intentionally leaves some of the very best trees for seed.
This kind of timber production is sustainable in both an economic and ecological sense. Not only does the overall gene pool improve, but periodic select harvesting creates openings in the forest canopy, increasing habitat diversity as it releases understory trees.
Many forest owners have heard of silviculture but continue to practice what some foresters call “silver-culture,” maximizing short-term gain at the expense of long-term forest health.
The prevailing opinion seems to be that doing the right thing for the environment will hurt you financially. Although that may be true in some instances, it is definitely not the case in forestry.
Dr. Ralph Nyland, Professor of Forestry at the State University of New York College of Environmental Science and Forestry in Syracuse stresses that forestry is a very long-term endeavor. He believes we have to start thinking much farther into the future.
Dr. Nyland illustrates why good forestry make the most cents—and dollars—in the following example:
Assume you and your neighbor have identical 100-acre woodlots with salable timber (everything 16” in diameter and larger) worth $20,000. Your neighbor goes for a diameter-limit cut and gets that entire amount. But you mark a select cut, harvesting $10,000 worth of timber and leaving trees of equivalent value standing. It sounds like your neighbor made out better, right?
The next time you can harvest is fifteen years later. By that time, your timber is worth $34,000. You harvest half, leaving $17,000 worth standing. Your neighbor doesn’t have enough salable timber for a harvest yet.
Thirty years after the first cut, your neighbor again has salable timber valued at $20,000.
Their total income plus residual value after 30 years is $40,000. Your timber, though, is now worth $77,000, which means that your total income plus residual value after 30 years is $104,000. Now we have two winners, both you and your woodlot.
OK, what do you call a poultry farmer who kills the goose that lays one golden egg each day just to get his hands on two or three gilded ova all at once? Well, for starters you’d call them fictional, but also dumb as a rock. Don’t manage your woodlot like that.
Good forestry will give you a healthy woodlot and a heathy bank account. “Silver-culture” will give you bad metaphors, less money and fewer good trees.
By definition, a weed is any plant growing where you don’t want it. To clarify, this holds true only in the garden beds or acreage under your cultivation. “Weeding” flowers in a park planter because they offend your sense of aesthetics is frowned upon.
To a plant, having “weed” embedded right in its name is probably akin to having a “Kick Me” sign on your back. Right out of the box there is bound to be a bit of prejudice against you, fair or unfair. Spotted knapweed, goutweed and Japanese knotweed are all pernicious invasive species, and deserve all the bad press they get. But occasionally an innocent bystander suffers from this name game.
The native plant commonly known as jewelweed (Impatiens capensis) is one of those exceptions.
A succulent plant that thrives in rich moist soils, it is nearly always welcome no matter where it is found. It’s an annual that is just as happy at the edge of the Arctic Circle as near the equator. Jewelweed has dappled orange, cornucopia-shaped flowers that attract hummingbirds and humans, though not necessarily for the same reason.
Hummingbirds and butterflies have been sipping nectar from its blossoms for who-knows how many millennia. While early settlers began dragging it back to north and central Europe as an ornamental beginning in the 1700’s, native peoples have valued it for thousands of years. Jewelweed may be unique in that it is at once a visual treat, a tactile diversion and a medicine.
Jewelweed is sometimes called touch-me-not, which might suggest one shouldn’t touch it. On the contrary, it should be handled. Jewelweed is “armed” with projectile seeds, and if you touch a mature seed capsule it will burst with surprising force, strewing seeds in all directions. Touching touch-me-nots is an activity that can amuse children (and some of us who never grew up) for long periods of time.
Poison ivy and jewelweed aren’t friends, but they like the same habitat and seem to have reached a certain rapprochement.
Toxic urushiol oil in poison ivy produces dermatitis in most people and a severe allergic reaction in some, but urushiol is neutralized by jewelweed sap. Jewelweed’s thick jointed stem is easily crushed, and you rub this juicy pulp over the skin where poison ivy has contacted it. It helps relieve itchiness caused by insect bites and nettles as well.
Although its reputation as a treatment for poison ivy and other rashes goes back centuries in oral traditions, jewelweed sap has not been well investigated for this purpose in controlled trials.
However, the sap has been used to treat athlete’s foot and other fungal conditions, something which does have has a basis in science—research has confirmed that jewelweed is antifungal.
A close relative of the ornamental impatiens varieties that we love for shady areas, jewelweed is not susceptible to impatiens downy mildew, a disease that has destroyed traditional impatiens in the past few years. Perhaps the key to developing resistant impatiens lies with jewelweed.
Its name may come in part from the way its leaves sparkle when held under water. The leaves are hydrophobic, not wettable, and myriad gemlike air bubbles adhere to them when submerged. It’s possible, too, that it was dubbed a jewel because of its important medicinal uses. Now if we could just get rid of the “weed” portion of its name.
When you think about it, trees in our landscape have it pretty rough. They don’t get to choose their neighborhood; good, bad or indifferent. Depending where they’re planted they may have to contend with “visits” from territorial dogs, “materials testing” by late-night fraternity mobs, entanglements with errant kites, and other issues.
Rooted in one spot day in and day out, year after year, they suffer from—well boredom, I imagine. And from restricted root area, drought stress, competition from turfgrass, reflected heat from pavement and buildings, deicing salt in the soil, that sort of thing.
But in recent years there has been an epidemic of seismic proportions that threatens the well-being of our beloved shade trees. Volcanoes. That’s right, over the past ten to twenty years we’ve had an outbreak of mulch volcanoes. They seem to erupt at the base of landscape trees, particularly young ones, and the results aren’t pretty.
Seismologists and botanists are hard at work trying to account for this phenomenon. Until a cure can be found, though, the public is urged to watch for rouge volcanoes in their neighborhood, and to report them to property owners. Be on the lookout for sudden eruptions of much around the base of trees. It can happen seemingly overnight, especially on commercial and institutional properties.
Banking mulch around the trunk of a tree can have severe detrimental health effects (for the tree, just to be clear). For one thing, insect pests are chickens. Like vandals and Internet trolls, they rarely do their dirty work in the light of day. No, they like it dark, and preferably damp, like under a pile of mulch (or in Mom and Dad’s basement, in the case of trolls). Wood borers and bark beetles love a mulch volcano because it gives them free access to the tree trunk.
Who doesn’t like a cute rodent? OK, some of us probably don’t. Trees aren’t fond of rodents either. Mice, meadow voles and pine voles all enjoy the taste of tree bark. The trouble is, eating it takes them a long time, during which they’re vulnerable to predators. But under a mulch volcano, lunch is on.
Tree roots need oxygen. This may seem obvious—of course they do, and they get oxygen through their veins, right? Well, no. Trees have vascular systems and they do make oxygen via photosynthesis, but they lack something akin to hemoglobin to transport oxygen to all their parts. Turns out that roots get their oxygen through the soil surface. Anything that obstructs access to the surface will smother roots. So, how long can you hold your breath?
Another problem is adaptation. Generally that’s a good thing. To the extent possible, trees are “self-optimizing.” They adapt and respond to changes in their environment. But mulch volcanoes are a different story.
When their trunks become buried by a mulch volcano, which limits oxygen to their natural roots, trees begin making adaptive, or adventitious, roots to compensate. Fine rootlets issue from the trunk in response to being smothered by wood chips. However, over time as the mulch volcano breaks down and subsides, those tender roots dry out and die, stressing the tree.
Finally there’s the issue of water. Transplanted trees may need additional water for several years. The rule is one additional year of watering for each inch of trunk diameter. Mulch volcanoes act like a thatched roof, shedding water very effectively. For a mature tree that’s not a problem, but a young tree may have all or nearly all its roots under that mountain of mulch, (not) nice and dry.
Maintaining two to four inches of mulch around a tree (twice the branch length is ideal) is beneficial, as long as the mulch doesn’t contact the trunk. Help stamp out mulch volcanoes in your lifetime!
For more information on tree care, contact your local Cornell Cooperative Extension, or new York State Department of Environmental Conservation office.
The term ‘blight’ strikes fear into the heart of anyone who grows tomatoes and potatoes, but it actually has no strict definition. It can refer to any number of plant diseases, from the innocuous to the truly pernicious.
For example, early blight, also known as Alternaria, is a soil-borne pathogen that kills the lower leaves of tomatoes and progresses up the stem throughout the season. Every garden has early blight, and while it’s usually not serious, it can be bad in wet years or if a lot of disease spores have built up in the soil.
Late blight, however, is a completely different kind of pathogen. Of all the plant maladies, I think the only one that deserves the fearsome moniker ‘blight’ is late blight, Phytophthora infestans. Its Latin name, roughly translated, means “highly contagious plant-destroyer.”
Late blight is airborne, so you can’t protect against it through crop rotation and other management practices the way you can with early blight and other garden-variety (so to speak) diseases. It affects leaves anywhere on the plant, not just the lower ones. It also infects stems and fruit, and can kill entire stands of tomatoes and potatoes in just a few days.
Weather plays a big role in the spread of this disease, and this year has been, well, the perfect storm for late blight. Sunlight kills late blight spores in less than an hour, but if it’s cloudy they remain viable for days, travelling long distances. Also, late blight needs moisture to germinate—it won’t infect a dry leaf. What have had in abundance this summer? Yeah, clouds and rain.
Late blight does not overwinter in New York, although it could potentially survive on an infected potato tuber. With the exception of that latter scenario, late blight spores get here from the far south on storm fronts. But once here, every infected plant becomes one of its spore factories, hastening its spread exponentially. This is why it’s so important for gardeners and farmers to destroy infected plants by bagging them up promptly.
Typical symptoms of late blight are large dark watery lesions (similar to lettuce that has been frozen and then thawed) on leaves, and dark brown lesions on stems. Brown, very firm lesions with a “greasy” look and feel will appear on tomatoes. In damp conditions some grayish “fuzz” may grow on the margins of these lesions.
As of late July, late blight has been confirmed in six NY counties, and two in western Vermont. Essentially we’re surrounded, and the weather continues to favor late blight’s spread.
If you think you may have it, don’t destroy your plants until you get confirmation. Bring a sample of leaves, and fruit if it’s tomatoes, to your Cornell Cooperative Extension office for diagnosis.
To protect tomatoes and potatoes, organic growers can use copper-based sprays to protect their plants, and home gardeners can use products containing chlorothalonil. Neither of these will cure late blight or even halt its spread, but are only meant to protect against initial infection.
Commercial growers with a pesticide applicator’s license can buy products which stop late blight. Chuck Bornt of Cornell’s Eastern NY Commercial Hort Program advises commercial growers:
“Once you see LB [late blight] on your farm or if you’re downwind of a farm that has LB, use the systemic or translaminar products such as Curzate + Previcur Flex (or other material) + a protectant. Tank-mix Curzate and Previcur Flex because Curzate has a short residual (especially in hot weather), but very good “burn out “activity. Adding Previcur Flex or another labeled translaminar material will greatly improve control. Because of resistance issues with Ridomil, I would wait until the strain has been identified before using it, although so far this year most of the LB strains identified have not been resistant to Ridomil.”
For daily updates on late blight, visit http://www.usablight.org/
PESTICIDE DISCLAIMER: Every effort has been made to provide correct, complete and up-to-date pesticide recommendations. Nevertheless, changes in pesticide regulations occur constantly, human errors are still possible. These recommendations are not a substitute for pesticide labeling.
Please read the label before applying any pesticide and follow the directions exactly.