joene's garden » invasive plants

Newsy Notes: Plant Pathogens, Butterflies, Invasive Plant Spread

joenesgarden — Sat, 20 Aug 2011 14:46:19 +0000

Newsy Notes features quick explanations of research related to the growing of plants. I come across this research during my daily sweep of plant-related information. I found the items noted below of particular interest. Follow the links for more in depth reading on each topic. The following were all published by ScienceDaily.

E. coli, Salmonella may lurk in unwashable places in produce:

Washing fruits and vegetables may not remove E. coli or Salmonella, report Purdue University researchers. After developing a method to look at pathogens in nutrient-transporting plant tissue they found E. coli in mung bean sprouts and Salmonella in peanut seedlings after the seeds of each had been contaminated with the pathogens prior to planting. Proper washing removes dangerous pathogens from the outside of food, but heating to a specific temperature is needed to remove them from inside tissues. This, of course, does not occur with fruits and vegetables consumed raw such as salad greens and bean sprouts. The next research step is to try and determine how the pathogens survive inside plant tissues, which may lead to methods of eradication.

Major breakthrough on how viruses infect plants:

Cucumber mosaic virus causes disease by directly matching a host plant gene associated with chlorophyll formation, found plant scientists with The Commonwealth Scientific and Industrial Research Organisation, Australia's national science agency. Like a zipper, one side of the gene - the virus side - directly matches the host plant gene. When scientists altered the host plant's genetic make up so it carried both copies, rather than one copy, of the chlorophyll forming gene the virus could not attack. With this knowledge, scientists can now search for genes in plant viruses that match plants' known genetic sequences in an effort to find ways to stop disease spread.

How butterflies copy their neighbors to fool birds:

Butterflies are truly amazing creatures. They migrate thousands of miles as part of their life-cycle and delight humans with their flittering and colors. Here's another amazing butterfly fact ... they can change wing patterns to fool birds, report researchers who studied wing color patterns of an Amazon butterfly species. Gene analyses in these butterflies showed they carry three versions of the chromosome that controls wing patterns. Butterflies, and apparently moths, alter wing patterns to make them less attractive to their specific predators. Fascinating!

Rural road maintenance may accidentally push spread of invasive plants:

When you think about this it's a no-brainer, but how many have actually considered that maintenance of a road bed in rural areas, such as grading work, can spread roadside invasive plants? Apparently it can, shows a computer simulation model developed by researchers at Penn State. They input field experiment data from spring road re-grading into their computer model to determine how this work might spread Japanese stilt grass. Though most of the sterile seeds used in their model remained within about 164 feet (50 meters) of their original location, a small percentage of seed moved more than 820 feet (250 meters). Of course, this is not the only way invasive plants spread, but it may help explain some spread.

NOTE: Click this link for more information on Japanese stilt grass in Connecticut. This invasive has quickly … and I mean quickly … invaded disturbed soils, lawns, roadside edges, and woodland edges in my neighborhood. It is currently the invasive weed I spend most of my time trying to control.

Categories: Gardening, General, Invasives, Newsy Items.
Tags: butterflies, invasive plants, Japanese stilt grass, Plant pathogens, ScienceDaily.

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Lyme-ticks thrive in Japanese barberry thickets

joenesgarden — Sat, 16 Apr 2011 10:00:00 +0000

This time of year the undergrowth of Connecticut woodlands begins to show a tinge of green. This color is certainly welcome relief after a long winter. Too bad so much of this color is due to invasive Japanese barberry (Berberis thunbergii de Candolle). This thorny shrub dominates unmanaged wooded areas. Deer don't eat it and birds spread it by eating and dispersing the shrubs' prolific fall berries. Japanese barberry quickly grows into large thickets that provide cover for mice and an ideal environment for immature blacklegged ticks - the very ticks that carry Lyme disease. In their early life, ticks are susceptible to desiccation – they need high-humidity at the ground level to thrive. Japanese barberry accommodate young ticks by leafing out earlier than most native shrubbery. The early leaves help maintain moisture levels at ground level by blocking drying sunshine.

This connection may not be a big deal if a tick simply lived its entire life in a barberry thicket. They don't. After ticks feed on mice they seek out host number two – commonly white-tailed deer. Fortunately for the ticks, Japanese barberry grows to a height that allows them easy access to passing deer. Ticks climb barberry stems where they hitch a ride on passing deer. Deer stroll from woodlands to yards and gardens, bringing their tiny passengers along for the ride.

We know this, in part, because of research from the Connecticut Agricultural Experiment Station in New Haven. Scott C. Williams and Jeffrey S. Ward have been monitoring the number of mice, the number of ticks and Lyme-infected ticks, and ground-level humidity in three geographic areas of Connecticut. In each area they have test plots of uncontrolled, controlled, and no Japanese barberry. For control, they used one of three methods.

One form involved torching the base of each shrub until the main stems carbonized and glowed – in effect girdling main stems to stop nutrient transfer. The dead shrubbery was left standing. The other two forms of control involved mechanically cutting the shrubs – usually by brush hog – and mulching cut plant material in place. They controlled regrowth with herbicides or flame from a propane torch applied directly to new sprouts. Note: Torching is acceptable control method for organic land care. It involves heating new sprouts by sweeping the flame back and forth over leaves until their cells burst – torching does not involve turning a large patch of land into a flaming inferno.

With a total of three years of data now collected, Williams and Ward estimate plots without barberry have 30 Lyme-infected ticks per hectare (the equivalent of 2.471 acres). By contrast, plots of uncontrolled Japanese barberry contain 280 Lyme-infected ticks per hectare. They report decreased humidity and suspect this led to «a near 60% reduction in the number of B. burgdorferi-infected adult blacklegged ticks,» in controlled plots.

They speculate continued barberry control will result in continued decline in tick populations and, therefore, suggest all landowners, managers, stewards «immediately initiate a management plan to address this alien invader.»

As Scott Williams explained for my report on his and Ward's previous Japanese barberry-tick study, mechanical control takes vigilance and follow-up. Effective eradication requires proper identification, mechanical removal of all above-ground portions in late-spring or early summer, allowing the shrubs' roots to use starchy reserves to force out new growth, then killing new growth in later summer. (Again, propane torch flaming is an acceptable organic land care practice.)

Do not cut barberry and expect it to die. As Williams notes, cut shrubs send up new growth with a vengeance.

Williams also advises against pulling a barberry shrub from the ground unless it is small and you can get all the roots. Any little rootlet may re-sprout. Again, re-checking for re-sprouting is vitally important.

I urge homeowners to take a few minutes to check their properties for Japanese barberry and, if found, to follow the control methods described above. This, and not planting any more Japanese barberry, may just cut your chances for Lyme disease.

Newsy Notes: Growing Organic Veggies, Invasive IDs, an Artificial Leaf

joenesgarden — Tue, 29 Mar 2011 14:36:20 +0000

Here's a list of few opportunities for local gardeners and wanna-be gardeners to hone their organic veggie growing skills and for those seeking outdoor invasive plant ID training, plus there's a peek into a new and very cool technology.

Growing Organic Vegetables
Want to grow vegetables organically at home but don't know where to start? Bill Duesing, the executive director of CT NOFA (Connecticut Northeast Organic Farming Association), will share his hands-on experience on April 19, 2011 at 7:30 pm at the Kellogg Environmental Center in Derby, Connecticut. Bill is an organic farmer when he is not advocating for healthy environmental land care practices. A CT DEP press release offers more information and registration contacts. With a $4 donation ($2 for students and children) you'll learn organic gardening practices from one of the best, plus it's hard not to catch Bill's enthusiasm for organic growing.

Other Organic Gardening Sessions
Connecticut Organic Gardening Education Day – April 2, 2011 – is a CT NOFA sponsored event at multiple locations, offering education on soils, compost and starting seeds. Growing Food in Small Spaces - April 9, 2011 in New Haven – offers tips on growing edible plants in a variety of containers.

Identifying Connecticut's Invasive Plants
A few hardy souls will have the chance to attend either of two one-day, hands-on, in the woods sessions on identifying invasive plants. Why is it important to do this now rather than wait until everything leafs out? Clearing invasive plants is best done when the soil is no longer frozen and most plants and trees are still dormant. But knowing which plant is invasive takes some practice and training, information field botanist Bill Moorhead will impart on a limited number of attendees during the April 1 and April 8, 2011 workshops. Read more about these sessions at the CT NOFA blog.

An Artificial Leaf?
I must admit when the headline Debut of the First Practical 'Artificial Leaf' caught my eye it conjured up something like the aluminum Christmas trees Charlie Brown and Linus passed by in their search for a real tree, but the artificial leaf this article refers to looks nothing like a real plant leaf. It's actually a new type of solar cell, about the size of a playing card, that converts sunlight and water into energy much like a leaf does - it photosynthesizes. Lead researcher Daniel Nocera, PhD, from Massachusetts Institute of Technology, reports the current solar cell design built on lessons learned a decade ago during development of a similar solar cell. The beauty of the new version is its use of readily accessible and inexpensive materials. The solar cell produces electricity by splitting water into hydrogen and oxygen. Extra energy is then saved in a fuel cell. Besides the coolness of this concept – it can be used in underdeveloped regions, works under simple conditions, and is stable - I'm particularly struck by Nocera's quote, "Nature is powered by photosynthesis, and I think that the future world will be powered by photosynthesis as well …"

What a concept … since nature is powered by photosynthesis, we might learn and succeed by copying nature. Nocera et al follow this concept in creating their solar cell. Less technologically-inclined folk can copy nature simply by gardening organically.

Categories: Edibles, Garden Blogs, Gardening, Invasives, Newsy Items.
Tags: 'artificial leaf', CT NOFA, gardening in Connecticut, Growing organic vegetables, invasive plants, photosynthesis.

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Newsy Note: Japanese Barberry

joenesgarden — Fri, 30 Apr 2010 10:50:50 +0000

Look into the woods of Connecticut during early spring and you'll likely notice stands of low-growing shrubs leafing out in an almost eerie lime-green. It's likely Japanese barberry (Berberis thunbergii DC) at its worst - invading our woodlands.

These imports from Japan now dominate large expanses of woodland undergrowth and crowd out native trees and plants - reason enough to find the thorny invaders objectionable. But scientists have uncovered more rationale to abhor the shrub; dense Japanese barberry thickets serve as favorable breeding grounds for Lyme disease-carrying ticks.

Scott C. Williams, PhD, and colleagues at The Connecticut Agricultural Experiment Station in New Haven compared three plots of land in Connecticut. They left one heavily infested Japanese barberry plot alone. In a second plot Williams' team controlled barberry thickets by cutting the shrubs down, then killing late-summer new growth with a propane torch. Their third study plot had no evidence of Japanese barberry.

William's team spent two years trapping and recording the numbers of white-footed mice in each plot, as well as the number of ticks feeding on the mice. They found the uncontrolled thicket of Japanese barberry averaged 6-to 7-times more ticks over the two years than the other two plots.

Barberry thickets give mice protection from predators serve host to one part of a tick's life cycle. William's group speculates the early spring leaf-out of barberry thickets creates the humid ground-level micro-climate in which ticks thrive. These two factors seem to give ticks a good jump start. Once done feeding on mice, barberry shrubs provide ticks the avenue - so to speak – necessary for the little blood suckers to complete another life-cycle phase. By climbing to the upper regions of the barberry shrubs they are able to catch a ride on passing deer.

Now if deer ate Japanese barberry, I doubt the shrubs would be so prevalent. But deer don't like the thorny invaders any more than humans, so Japanese barberry thrives, mice thrive, ticks thrive, and deer certainly thrive in Connecticut woodlands. The combination may create the perfect Lyme-disease storm.

But before you grab a machete or other instrument of destruction to attack barberry thickets, understand the shrub is not easily controlled. Williams suggests a two-step process:

· First mechanically remove the above ground portion of the shrub in spring or early summer. For heavy stands a brush saw or tractor-mounted brush hog works best.

· Then allow the shrub to use some reserved energy to shoot-up new growth. In late summer kill new growth with either an herbicide or a propane torch.

The second step is vital. Left alone the shrubs will grow back «with increased vigor,» Williams told me in an email. Forget to follow up and after one growing season your cut-down barberry thicket will look like you've done nothing.

Hand pulling might work if you are lucky enough to find just a few small barberry shrubs in your area. «It's a heck of a lot easier to get rid of them before they form an impenetrable thicket,» Williams said. But «any little rootlet left in the soil has the potential to re-sprout into a mature plant.»

Again, regular vigilance is needed to eradicate Japanese barberry.

The Invasive Plant Management Guide from UConn offers more detailed Japanese barberry obliteration methods. Click on the Woody Plant link, then on Japanese Barberry. Additional photos from Invasive Plants of the Eastern U.S. will give you a better idea of the shrub's many stages, including the bright red berry stage. Birds eat the berries, do their bird do-do from whatever perch they choose, and voila, barberry spreads.

Even more photos and links to information on Japanese barberry's impact in other state comes from Invasive.org and the USDA Plants database.

Massachusetts prohibits the sale of Japanese barberry. There's some move toward a voluntary ban on sales of certain Japanese barberry cultivars in Connecticut. All homeowners, gardeners, and landscapers should avoid buying and planting Japanese barberry.

Personally, I don't understand why anyone wants these shrubs in their landscape – I have yet to see a cultivar I find attractive. Considering the negatives, doesn't it make more sense to just avoid planting Japanese barberry?

Stay tuned. Debbie, at A Garden of Possibilities, plans to alert readers on any ban updates in Connecticut, and Williams told me he is in the process of compiling information from continued samplings of the original plots. His team has also continued to manage barberry thickets using only propane torching and he plans to report on these findings as well.

Categories: Gardening, Newsy Items, Techniques.
Tags: control, eradication, gardening in Connecticut, invasive plants, Japanese barberry.

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Autumn Joys, part deux

joenesgarden — Fri, 30 Oct 2009 15:23:18 +0000

Now is the time to get out and enjoy the last of the fall colors in southern Connecticut. While outside wandering … whether aimlessly or not … look high to grab a mental snapshot of New England's breathtaking fall colors. But also look down to take note of color changes lower to the ground. Often, perennial plantings put on their own show each fall. Low-growing sedum, once bright green, now displays it's autumn hues.

Shorter grasses, like this pennisetum, add color and structure.

Also, while enjoying the view, keep a sharp eye out for any bittersweet vines. I do a thorough bittersweet search in the spring, but fall is also a good time to attack this invasive vine.

In the photo below you can see the green bittersweet leaves giving themselves away at the top of a native blueberry bush. This bittersweet easily could have grown from a small shoot to this in one season. Pull bittersweet now, before the ground freezes and, if possible, burn the vines in an outdoor firepit so birds cannot eat the seeds and further spread the tree and bush destroying vine.

Categories: Gardening, Seasons, Techniques.
Tags: Autumn beauty, bittersweet vines, invasive plants.

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