Tag Archive for late blight

Late Blight – The Sequel

It’s baaack … Connecticut Agricultural Experiment Station (CAES)recently issued the following:

-Alert for Late Blight of Tomato and Potato-

Late blight was identified on tomato plants from New Haven County on Thursday, 17 June 2010.  If you think you have seen late blight in your greenhouse, garden, or on volunteer potato plants, please contact The Plant Disease Information Office (203.974.8601).  You can also send or bring in samples for diagnosis.

Here’s a quick synopsis of the CAES late blight fact sheet:

This year tomatoes and potatoes are at high risk for  Phytophthora infestans (phyto is Greek for plant and phthora means destroyer), aka late blight, because of 2009’s widespread outbreak throughout Connecticut and the northeast. P. infestans overwinters in potato tubers.  Heavy rains, overhead watering, and soil disruption transports the pathogen to new plants. Infection becomes visible in 3 to 5 days and continues to grow at an alarming rate. Each individual lesion produces from 100,000 to 300,000 sporangia per day and each of these tiny buggers can go on to infect anew. Late blight can also infect other Solanaceae plants (eggplant and peppers for example) and ornamental hybrid petunias. Wind-blown sporangia can travel many, many miles.

CT’s Ag Station says the pathogen does not survive in soil, plant debris, or in tomato seeds. But when I listened in on a  2009 late blight teleconference by Cornell scientists they said late blight can survive in soils for as long as 8 years.  Either way, this is one plant destroya that lives up to its name – late blight is not to be messed with. Stopping/controlling it requires daily plant inspections and immediate removal and destruction (in sealed plastic bags) of all plant material. DO NOT COMPOST infected plants or fruit. I have not yet found a clear answer as to whether it is ok to burn infected plants in an outdoor fire pit. Please respond here if you know the answer.

Olive brown lesions on plant stems, 1/2 to 3/4 inch olive brown lesions – some with yellow margins – on leaves, and dark brown, rapidly expanding lesions on fruit are all signs of late blight. Similar fungal diseases on tomatoes  include Septoria lycopersici leaf spot, usually on lower leaves which then turn yellow and drop off, (I have leaf spot every year) and early blight, Alternaria solani, which causes dark brown/black 1/2 inch dead spots that enlarge to concentric rings (a bull’s eye). Follow this link for photos of tomatoes infected with late blight, Septoria, and early blight, and to read the entire tomato blight fact sheet.

More late blight info:

tomato1Don’t think you are safe because you missed last year’s outbreak and grew your plants from seed. An alert from CT NOFA (Northeast Organic Farming Association) confirms late blight in a backyard garden with no previous late blight problems and in tomatoes home-grown from seed. After a quick check in my gardens I can breath a brief sigh of relief – my tomatoes, so far, look healthy. Cherry tomatoes are beginning to fruit, and Pruden’s Purple, Roma, and Manyel plants are all in flower. But you can be sure I will check them daily for signs of late blight.

Newsy Gardens & Plants – April 16, 2010

tree fungi (2) Interested in digging deeper into the world of fungi and other tiny non-plant, non-animal organisms, check out the book by Steven L. Stephenson, a research professor of biological sciences at the University of Arkansas.  In The Kingdom Fungi: The Biology of Mushrooms, Molds, and Lichens (published by Timber Press), Stephenson explains the purpose, forms, and roles of these commonly misunderstood life forms.  Gardeners know fungi do more than adorn a fresh salad or top a pizza, but how many of us really understand the true extent fungi play in our lives.  Stephenson’s author profile notes he has studied fungi and slime mold on six continents – sounds like he’s a real fun-gi (guy) – sorry, couldn’t resist.

Here’s an intriguing vision for gardeners plagued with Japanese beetles:

  • beetle eats petals,
  • beetle rolls over on its back with legs and antennae twitching,
  • beetle remains paralyzed for several hours.

“The beetles typically recover within 24 hours when paralyzed under laboratory conditions, but they often succumb to death under field conditions after predators spot and devour the beetles while they are helpless,” according to an article in the March 2010 Agricultural Research magazine.  What petals, you wonder?  Those of Pelargonium zonale – that’s right common, everyday geranium.  Scientists are analyzing specific extracts of geranium petals to determine which compounds stop the beetles in their tracks.  I wonder how I could entice Japanese beetles in my gardens to munch on geranium petals rather than roses, hibiscus, and other flowers?

The same issue of Agricultural Research reports the sequencing of the complete genome of Phytophthora infestans – potato late blight – the same pathogen that attacked so many tomato and potato crops in eastern U.S. gardens last season.  Sequencing allows scientists and researchers to better study how late blight works and seek ways to stop it.

Ever wonder where some of the most common varieties of strawberries come from?  At least three – Earliglow, Tribute, and Northeaster come to us via work done by the Agricultural Research Service.  Since I’m looking to build a strawberry bed into my new vegetable garden design I hope anyone with experience growing any of these varieties, or others, will pass on their experiences.

volunteer cherry tomatoes - Copy Finally, some stats from the Garden Writers Association offer demographic information on gardeners in the U.S.  Randomly conducted telephone surveys of nearly 600 people show:

  • 50 and 26%, respectively, have gardens in their back and front yards,
  • 54% of these purchase their spring garden plants from a local nursery/garden center, while 37% do so at big-box stores,
  • 37% go to retailers for advice on spring garden planning, 37% ask neighbors for advice, 34 and 31% gain advice from books and magazines, 29% use garden websites, and 7% use blogs for the same,
  • 66% who have a garden will grow vegetables – this is 2% more than in 2009,
  • of the respondents 31% were 35 to 44 years old, 17% were 45 to 54 years old, and 19% were 55 to 64 years old; 14% were younger than 34 and 18 percent were older than 65.

Late blight marches on

August 11, 2009.  Late blight continues to rear its ugly head in Connecticut farms and gardens, according to a recent report in the Norwich Bulletin.  Because of the high risk of this windborne fungus spreading from location to location, I check my tomato plants daily. The Connecticut Agricultural Experiment Station’s Department of Plant Pathology and Ecology posted images of CT grown tomatoes with late blight.  For images of all types of tomato disease, visit Cornell University’s Vegetable MD Online.

Roma tomatoes 8-11-09 Pruden's Purple - unripened 8-11-09 My Roma tomatoes (left) are just beginning to ripen but my Pruden’s Purple (right) still have a way to go before they achieve full vine-ripened goodness.  I’m prepared, though, to pull – and burn – each and every plant at the first sign of late blight.   I cross my fingers every morning as I approach the vegetable garden for inspection.  So far so good for my tomatoes, but I feel for the many farmers and gardeners who  have lost tomatoes and potatoes to late blight this year.

For more info on late blight, check out my previous posts, accessible by clicking late blight under the tags list in the right sidebar.