~Hudson
Valley Horticulture~ Cornell Cooperative Extension of the Hudson Valley ~~~~~~~Commercial Horticulture Electronic Newsletter~~~~~~~ Volume 6, Issue 8 August 7, 2006 |
Participating Counties: Dutchess * Orange * Putnam * Rockland * Sullivan
* Ulster * Westchester *
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Plum Pox Found
in NY For further information click on the following links: Submitted by James Lee, Cornell Cooperative Extension of Westchester County Return
to Index Submitted by Teresa Rusinek, Cornell Cooperative Extension of Ulster County Research on
Heat and Plant Productivity The Agricultural Research Service has been actively involved in researching the correlation between rising temperatures and plant productivity as part of their Global Change national program. The research is being carried out in growth chambers in natural sunlight and temperature-gradient greenhouses in Gainesville, Florida. Each crop studied was found to have its own optimal mean daily temperature (OMDT). As temperatures climbed, it was found that yields decreased as some plants stopped setting seeds. Seed productivity declined by about 6% for every 1 degree F above a given plants OMDT. The ultimate goal of this research is to utilize traditional breeding to develop crops with a built-in heat tolerance. With temperatures on the rise throughout the country, this research could help decrease the agricultural impact of climate change. The entire article which appears in the August 2006 issue
of Agricultural Research can be read on-line at http://www.ars.usda.gov/is/AR/archive/aug06/ Poison Ivy
Gets Pumped Up One of the scourges of summer is dermatitis from contact
with poison ivy. The leaves, branches, and roots of this perennial vining
weed contain an oil (urushiol) that, once it penetrates your skin, can
cause itching and scratching for weeks. Worse yet, the oil remains active
on clothes, tools, and gloves and can reinfect you even when youre not
working in the garden.
The targets of the three-year study which is being led by entomologist Lindsey Milbrath of the ARS Plant Protection Research Unit (PPRU) in Ithaca, N.Y. are two members of the milkweed family known as pale swallow-wort and black swallow-wort. Both plant species originated in Europe. Pale swallow-wort (Vincetoxicum rossicum) comes from the Ukraine, and black swallow-wort (V. nigrum) is from southwestern Europe. On their home grounds, both are kept in check by native natural enemies, particularly insects and diseases. But so far, nothing on these shores has halted their advance. According to Milbrath, the vines contain strong and unique poisons that probably limit natural enemies here and keep deer and cattle from feeding on them. Cornell research has shown that the pink-flowered pale swallow-wort grows rapidly in forest understories and in open fields of undisturbed soil throughout central and upstate New York, around the Great Lakes and in Canada. The purple-flowered black swallow-wort prefers open areas. Its found primarily in New York's Hudson Valley and Long Island, as well as throughout New England. Although both swallow-worts share the ominous "dog-strangling" moniker, theyre actually a threat to Monarch butterflies. Pale swallow-wort may be replacing common milkweeds in open fields upon which monarch larvae feed. The butterflies' larvae are unable to survive on either plant species. Also, the vines have pushed onto reduced-tillage corn and soybean fields and impacted forest regeneration. Cornell Cooperative Extension Dutchess County (Farm and Home Center) is a research study site for black swallow-wort. Researchers from the USDA-ARS are studying growth habits and biology of this invasive weed. Written by Luis Pons, USDA - ARS, June 2006 Submitted by Rick W. Harper, Cornell Cooperative Extension
of Westchester County One visit to your local garden center and its clear that
mophead hydrangeas (Hydrangea macrophylla) are very popular. While pink
or blue flowers have been the most popular colors, plant breeders also
have been working on new red selections. Up until now, most red hydrangeas
have produced flowers that are more lavender or deep pink. However,
Hornli breaks the mold. Hydrangea macrophylla Hornli produces fire engine
red flowers on a dwarf plant that's perfect for a container or flower
garden. Hornli grows only 2 feet tall and wide and produces 3-inch-diameter
blooms on old wood, so it will need protection in colder areas. Its
hardy in USDA zones 6 to 9. Batdorf, a horticulturalist, has been curator of the arboretum's National Boxwood Collection since 1977, carefully tending about 150 different species and cultivars in one of the world's most complete boxwood collections. The arboretum is operated by the USDA's Agricultural Research Service (ARS). Batdorf, who recently discussed his boxwood collection efforts at the 46th American Boxwood Society Meeting and Symposium in Memphis, Tenn., in 2002 began exploring for boxwood in Azerbaijan, a former Soviet republic that is home to many rare species. Foreigners have only recently been allowed to visit that country for plant exploration. During an expedition to the Chirkan Nature Reserve, in the towns of Lankaran and Astara, Batdorf discovered Buxus colchica, a very large (30 feet tall) and ancient (over 250 years old) boxwood. In January 2006, Batdorf registered a new Korean semidrawf boxwood (Buxus sinica var. insularis), dubbed Wee Willie, in the Boxwood Bulletin, a quarterly journal of the American Boxwood Society (ABS). This boxwood has straight, vertical stems with dense, dark-green leaves and excellent cold hardiness. Other valuable boxwood in the arboretum's collection includes Vardar Valley (Buxus sempervirens) from Macedonia, a variety known for its fragrant flowers, shallow roots, and resistance to leaf miners and mites. Another notable variety is Curly Locks (Buxus microphylia), a medium-sized plant with small, curly leaves. Written by Alfredo Flores, USDA-ARS, May 2006 The 2006 New England Greenhouse Conference Featuring Alternative Crops including Greenhouse Tomatoes, Salad Greens and High Tunnel Production of Cut Flowers The New England Greenhouse Conference will be held November 1-3 at the DCU Center in Worcester, Massachusetts with a trade show on November 2nd and 3rd Wednesday, November 1st, is a pre-conference day featuring in-depth workshops and short courses. The third day of this year's conference will offer workshops of interest to vegetable growers and greenhouse growers looking to extend their season. If you've never been to the New England Greenhouse Conference before this is a great opportunity to see what it's all about! Vern Grubinger, Director of the Center for Sustainable Agriculture at the University of Vermont, will be speaking on the organic production of greenhouse crops, focusing on tomatoes. Vern will cover the requirements for organic greenhouse production and discuss the specifics of growing greenhouse tomatoes. Eliot Coleman, author, and part owner and operator of Four Season Farm in Maine, will be speaking on the greenhouse production of salad and root crops using no heat! Eliot will share his production strategies on growing a variety of profitable crops over the winter months. The theme of season extension continues with several presentations on cut flowers. Mark Bridgen from Cornell University and Ted Blomgren from Windflower Farm in New York will cover cutting edge research plus a farmers practical experience on using high tunnels for cut flower production. Greg Berger from Springledge Farm in New Hampshire, will discuss how he successfully grows and markets his cut flowers, which are sold, at his farm stand and as a profitable U-Pick crop. Susan Han from the University of Massachusetts will talk about harvesting and caring for cut flowers. Learn the whys and how tos of handling cut flowers for maximum longevity. This session is a must for anyone handling and selling cut flowers! To be added to our mailing list to receive the 2006 New England Greenhouse Conference Program or for more information, contact: Cindy Delaney, Show Coordinator, 1 Main Street, No. 36, Winooski, VT 05404, Phone: 802-655-7769, Fax: 802-655-7769 Email: delaney@sover.net or visit our web site: www.negreenhouse.org November 3, 2006 ~ Bethesda, Maryland Dutchess County I won't say the cliche...heat wave! But it's been hot! Japanese beetles are once again abundant this year. Adults are still active and it is expected that mating has begun. Larvae will be detectable by the end of the month if not sooner. We are still seeing a lot of winter damage on conifers. Coupled with drought damage from last year, many conifers are struggling. A recent visit to a local Christmas tree farm showed Fraser fir damaged by the heavy spring rains on soils where the moisture just sat. Our diagnostic lab has received samples of digger wasps. These wasps like to burrow tunnels in turf to lay their eggs . Though they appear to look menacing, they are really harmless. Most "dodging" digger wasps are actually males protecting their territory. Since males do not have an ovipositor, they cannot sting. Cicada killer wasps also burrow into the turf to provision a nest for their young. They too are more intimidating than dangerous. Written by Stephanie D. Mallozzi, Cornell Cooperative
Extension Dutchess County Putnam County has been beset by fungal diseases. Turf
problems include brown patch, melting out and stripe smut. Vegetables:
powdery and downy mildew on curcurbits. Apples: Apple scab, wet rot,
fly speck. Peaches: brown rot. While control methods (thiophanate methyl
and Clearys 3336F, for example) are effective on some turf diseases,
the conditions that encourage fungal spore growth are still with us. Heat seems to be the cause of most of the turf and plant
problems we are seeing in our diagnostic lab. Summer dormancy of turf
is becoming more prevalent. Many lab visitors have been bringing in
samples of hydrangeas with browned out flowers. This, too, is a symptom
of recent heat stress. The lab is also seeing numerous samples of the
typical summer problems of powdery mildew, scab, and black spot. Several samples of Juniper have come into the lab with symptoms of browning. The cause in some of our earlier samples was determined to be winter injury. Recent samples have been diagnosed with spruce spider mites and Phomopsis tip blight. Spider mites are small (almost microscopic) creatures that feed on the sap of many plants. There is a type of spider mite that really loves junipers called spruce spider mite. As they draw the juices from the plants, the infested part of the plant turns brown. Their populations can build up very rapidly so the damage can seem to appear overnight. A web material they produce often coats the twigs they infest. The mite webbing maintains a higher humidity in the mites' environment and protects the spider mites from predators. Unlike many other spider mites, this spider mites activity typically declines in mid summer as temperatures rise and conditions become dry. Activity usually picks up again in the fall. Phomopsis tip blight, caused by the fungus Phomopsis juniperovora,
damages new growth and succulent branch tips of junipers from mid-April
through September. Older, mature foliage is resistant to infection;
therefore, most blighting occurs on the terminal 4 to 6 inches of the
branches. Affected foliage first turns dull red or brown and finally
ash-gray. Small gray lesions often girdle branch tips and cause blighting
of foliage beyond the diseased tissue. Small, black, spore-containing
fungal fruiting bodies develop in the lesions. Use a hand lens to view
these diagnostic fungal structures more easily. Spores of the Phomopsis
fungus are produced throughout the summer, and infection can occur whenever
young foliage is available and moisture or humidity is high. Most infections
usually occur in April through early June and again in late August through
September. Tip browning is often evident by late May. With juniper problems,
it is always a good idea to have the problem diagnosis confirmed by
a diagnostic laboratory. The month of July has indeed proven to be a warm, wet one as indicated by the amount of precipitation (23.06" at Westchester County Airport - almost 4" above normal) and the end of month Growing Degree Day count (1753 GDD; 119 GDD units above the average for this time of the year). Our phone calls have included questions about summertime patch diseases on turf (Brown patch) as well as leaf spot (Dreschlera sp.). During the month of August, our cool-season turf grasses generally cease growing and turn consistently brown throughout a given area - a process simply known as going 'dormant'. If dormancy is the suspect behind the browned area of turf don't panic because as temperatures cool, the grass will begin green up and grow again. During our field site visits, we have observed many of the usual diseases that occur on ornamental plantings during this time of the year including Powdery mildew on Lilac, Phlox, Peony, and other ornamentals, and Black spot on Roses. Feeding damage from pests active earlier in the season like Spruce Spider Mite can be observed on plantings such as Alberta spruce. Other mite populations including Two-Spotted Spider Mites have been observed damaging a number of ornamentals including Butterfly bush and vegetables including Tomatoes. Guignardia leafblotch has been noted on Horse-chestnut and of course our Elm trees are exhibiting the characteristic symptoms consistent with Dutch Elm Disease or Elm yellows (i.e. notable branch dieback, leaf loss, etc.) during this time of year as well. We have received a number of samples in our lab including, Impatiens that were suffering from root rot caused by Pythium sp. and Black root rot on Petunias. It is important to remember that although watering can be important during this time of the year, do it judiciously - generally 1" of water per week (including rainfall) for most landscape plantings. To view pictures or read up on any of the diseases that
were mentioned above, visit Cornell's Plant Disease Diagnostic Clinic
at:http://plantclinic.cornell.edu/ A printable version of the Hudson Valley 2006 Regional Horticulture Program Calendar is available online at the following link: http://www.cce.cornell.edu/ulster/Ag/AGEVENTS.htm ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ If you're not
already a member, please consider joining the Tri-County Nurseryman/Landscape
Association, Region 7 of the New York State Nursery/Landscape Association.
It's a great way to network, learn and meet other people within our
industry. Certified
Landscape Technician Training |
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