Monthly Archives: September 2015

Late Blight on Long Island – Did We Dodge the Bullet?

While gardeners and farmers elsewhere, including upstate New York, have been battling late blight in 2015, so far it hasn’t been found on Long Island! At least, not yet . . . This is the first year since 2008 that this highly contagious and very destructive disease of tomatoes and potatoes hasn’t been observed here in spring and summer. Its absence means that on Long Island, we are successfully managing plant sources of the late-blight pathogen, Phytophthora infestans, in three ways by:

  • not planting infected potato tubers to grow new crops
  • not leaving infected potato tubers from previous crops in the ground or putting them in cull or compost piles
  • not planting infected tomato seedlings
We all dread seeing these symptoms of late blight appear on our tomatoes!

We all dread seeing these symptoms of late blight appear on our tomatoes! Photo by Meg McGrath.

But one source of late blight remains on the scene and continues to be a threat until frost: spores blown long distances by wind. Typically spores of Phytophthora infestans blow no more than about 30 miles, but their farther wind dispersal is possible. A Long Island outbreak of late blight in August 2007 was, I think, the result of a storm carrying spores here from Lancaster, Pennsylvania. And in October of 2002 and 2008, late blight made its first appearance of the year on Long Island. There have been reports recently of late blight in New Jersey, so we’re not out of the woods yet.

Here is when late blight was first observed on Long Island in recent years:

  • October 3, 2002
  • July 5, 2006
  • Aug 26, 2007
  • October 3, 2008
  • June 23, 2009
  • June 18, 2010
  • June 24, 2011
  • May 29, 2012
  • July 25, 2013
  • June 20, 2014

Do you want to know where late blight has been reported in the United States this year? Check out www.usablight.org. Anyone can sign up on this website to get an alert by text or e-mail when a report has been logged nearby, so you can be one of the first to know when late blight has been found on Long Island. But realize your plants could be the first affected; therefore, signing up for alerts is not a substitution for looking for symptoms at least once a week. My own garden plants were part of the August 2007 outbreak!

Considering the potential impact of late blight, everyone who grows tomatoes and potatoes is responsible for inspecting their plants for late blight, reporting it when seen, and managing affected plants to minimize its spread. Photographs and information about late blight are posted on my website at: http://livegpath.cals.cornell.edu/gallery/tomato/tomato-late-blight/

If you see symptoms you think might be late blight (rather than one of its imitators, also shown on my website) call our Horticulture Diagnostic Lab at our hot line at 631-727-4126 from 9 a.m. to noon, Monday through Friday, where Alice Raimondo and Sandra Vultaggio, our Horticulture Consultants, can help determine whether you do, indeed, have late blight, even this late in the year.

Dr. Meg McGrath is Associate Professor at Cornell University’s Long Island Horticulture Research and Extension Center in Riverhead, New York, where she conducts research and extension activities to help farmers manage diseases.

Tomato Troubles? There’s an App for That

As Cornell University’s vegetable pathologist doing research at the Long Island Horticulture Research and Extension Center (LIHREC) in Riverhead, NY, I’ve seen a lot of sick tomatoes over the years, and I’ve been posting photographs of what I’ve seen on my website: http://livegpath.cals.cornell.edu/gallery/. When not at work, I’m an avid home gardener, too, so I have first-hand experience with the diseases popping up in Long Island gardens. In fact, many photographs on my website were taken at home.

Septoria leaf spot symptoms usually first appear on the lowest, oldest leaves after fruit start to ripen.

Septoria leaf spot symptoms usually first appear on the lowest, oldest leaves after tomatoes start to ripen.

This year my tomatoes have Septoria leaf spot, which started on one plant and has been slowly spreading to others. The spores of this fungal pathogen, Septoria lycopersici, are spread by splashing water. It hasn’t rained much this summer, and I usually water at the base of plants rather than use an overhead sprinkler, but the few rains we’ve had spread the pathogen a lot. Septoria gets into a garden when seed containing the pathogen or infected seedlings are planted, or a windy rainstorm moves it from a nearby infected plant. Once in a garden, this pathogen survives overwinter in tomato debris; hence the recommendations to remove infected plant debris and to rotate the areas where you grow tomatoes. Other diseases and disorders I’ve seen on my garden tomatoes include anthracnose and blossom end rot (both every year), drought stress on leaves, leaf mold, powdery mildew, and late blight, all of which appear on my website.

Small dark brown spots with tan centers containing very tiny black specks called pycnidia (spore structures) are characteristic of Septoria leaf spot.

Small dark brown spots with tan centers containing very tiny black specks called pycnidia (spore structures) are characteristic of Septoria leaf spot.

Recently some colleagues and I at the American Phytopathological Society, including Dan Gilrein and Margery Daughtrey from LIHREC, developed a new app for smart phones called Tomato MD. It costs $2.99 and is available for both Apple and Android phones. Learn more about it here: http://www.apsnet.org/apsstore/shopapspress/pages/apps.aspx

This interactive reference tool is set up for fast identification of tomato problems, based on symptoms of root, leaf, stem, and fruit. The goal of the app is to move you quickly through the most difficult part of dealing with a sick plant: what’s wrong and what is causing it. The app includes an index of nearly 30 diseases and insect disorders, an extensive photo gallery of the most common problems, and a list of diseases according to their characteristics. Tomato MD does more than just help with identification; management tips are included, too.

For more help in identifying what’s wrong, take a look at my website (above), then read our online fact sheets about dealing with tomato problems, which can be found here: http://ccesuffolk.org/gardening/horticulture-factsheets/vegetable-diseases. If you’re still stumped, call our Horticulture Diagnostic Lab at our hot line at 631-727-4126 from 9 a.m. to noon, Monday through Friday, where Alice Raimondo and Sandra Vultaggio, our Horticulture Consultants, are available to answer all your horticulture questions.

Dr. Meg McGrath is Associate Professor at Cornell University’s Long Island Horticulture Research and Extension Center in Riverhead, New York, where she conducts research and extension activities to help farmers manage diseases.

Buff Up Your Conservation Buffers

Because Long Island is surrounded by water, responsible residents strive to keep pesticides and fertilizers from polluting our coastal and drinking water resources. And as stewards of our land, we need to preserve as much habitat for wildlife as possible. One way to accomplish both goals is to plant garden or conservation buffers. These small pieces of land with permanent vegetation help control pollution while providing undisturbed habitat for wildlife. Examples of buffers include riparian buffers, small wetlands, shallow water areas, herbaceous and woody windbreaks, contour grass strips, living snow fences, and field borders.

Garden buffers like this one at Cornell Plantations in Ithaca can be used to filter polluted run off from parking lots.

Garden buffers like this one at Cornell Plantations in Ithaca can be used to filter polluted storm-water run off from parking lots. Photo © Robin Simmen

Although you may view them primarily as pleasant landscape features, buffers quietly prevent soil erosion, improve soil and water quality, enhance fish and wildlife habitat, reduce flooding, conserve energy, and ultimately conserve biodiversity. By capturing up to 75 percent of flowing sediment and by enhancing infiltration, buffers trap heavy metals. When properly installed and maintained, they can remove up to 50 percent of pesticides and nutrients from polluting coastal waters!

In addition to providing wildlife habitat (increasing the number and diversity of birds and butterflies) and creating corridors for their movement, buffers are attractive, low-maintenance, sustainable alternatives to traditional turf. Water moves more slowly through shrubs and other buffer plantings as compared to turf, thus reducing your irrigation needs. Conservation buffers can also improve your quality of life by reducing noise from the street and odors from garbage.

An added benefit is that buffers help reduce flooding. They also help stabilize streams, enhance biodiversity by providing micro habitats, and decrease and then stabilize water temperature. Fluctuations in water temperatures and warming can be very deleterious to fish and other aquatic creatures important to the stream food chain.

A shallow water area or a small wetland is a place where water depth is usually less than 2 feet with no more than 10 percent of the entire area being over 4 feet deep. These wet areas may be seasonal in nature, such as vernal pools, so you might be tempted to “dry ‘em out or fill ‘em in,” but DON’T DO IT! Not only is it often illegal to do so, but such spots are of particular importance to certain plants and animal species that depend on transient moisture for parts of their life cycles, e.g. reproduction or nesting.

To learn more about how to construct a conservation buffer on your property or how to evaluate your existing landscape, please join me and Joann Gruttadaurio, Senior Extension Associate Emerita, Cornell University, on October 15, 2015, 9:00 a.m. until noon, at the Suffolk County Farm for a hands-on workshop on how to “Buff Up Your Soil and Garden Buffers.” The cost is $30, and preregistration is required. Click here to download the registration form.

Dr. Tamson Yeh is CCE Suffolk Turf Use and Land Management Specialist. She can be reached at tsy3@cornell.edu or 631-727-7850 x240.

Best Way to Water Your Lawn

Question: I water my lawn every day, but it still looks like it’s drying out and turning brown. What is the correct way to water?

Answer: Usually there’s plenty of rain on Long Island during April, May, and sometimes well into June, but this year we weren’t so lucky. And summer rainfall has not been forthcoming. Most lawns need an inch or so of water each week to stay green, which is approximately how much moisture they lose weekly through evapotranspiration.

I suspect you are running your sprinklers for twenty minutes or so daily. Unfortunately, this means you are wasting lots of water and not helping your lawn. A brief daily shower only moistens the grass blades and doesn’t deliver enough water to the turf roots, which is why your lawn is going into drought stress.

Daily watering resulted in the drought-stressed lawn at the top of this picture. Compare it with the next-door neighbor's healthy lawn at the bottom, which receives one-inch of water just once a week.

Daily watering led to the drought-stressed lawn at the top of this picture. Below it, the next-door neighbor’s green grass receives only an inch of water once a week.

The best way to water your lawn with an inch of water is to soak it just once a week, which may take several hours depending on your water pressure and sprinkler heads. You can determine how long your system takes to supply one inch of water to your lawn by setting several empty tuna cans inside the spray pattern of your sprinklers and watching until they fill up to one inch; or you could buy a few inexpensive plastic rain gauges.

Late summer storms often supply ample amounts of water. As summer winds down, keep track of how much rainfall you get; then adjust your irrigation accordingly. Learn more about correct watering practices by looking at Suffolk County’s Healthy Lawns, Clean Water website, which discusses this in greater detail: http://healthylawns.suffolkcountyny.gov/lawn/watering.htm

Alice Raimondo is Horticulture Consultant for CCE Suffolk. She can be reached at aw242@cornell.edu or 631-727-77850 x335.