Tomato Blight: The Worst Outbreak in Years

Posted by Cathy England
August 30th, 2009
Filed in Garden Pests and Diseases
Tags: crop rotation, diseases, garden hygiene, Tomato blight

Any gardener living in the northeastern regions of the United States has probably some knowledge of the devastation of the tomato blight this year.  Brown spots, yellowing leaves, decreased production.  It is particularly frustrating if you are an individual who relies on tomatoes to can or freeze for use later in the year.

The Cause of This Year’s Outbreak

Late tomato blight is a disease that often appears late in the summer affecting only a few plants, and resolving itself after a while.  It is a different strain of the potato blight that devastated the economy and livelihood of residents of Ireland in the 19th century, leading to a mass exodus to the United States.  While tomato blight is not likely to cause such far reaching deterioration of the economy, the price of tomatoes and tomato products is quite likely to rise.

There are a few factors that are believed to have contributed to what is being called the most severe and widespread blight in recent history.  The first factor is due to the fact that for many in the northern and eastern regions of the United States, it was a cold wet spring.  The spores of the fungus can travel by air, or overwinter in the soil from previous years.  They are spread most easily when water is splashed on the plants, or when a gardener tends to plants while they are wet.  If you have picked your own tomatoes at a farm, you may have found that they do not allow picking while the plants are wet.  This is the reason why.

Researchers are also pointing to tomato transplants sold in the garden centers of the big hardware and retail stores.  Specifically, the distributor Bonnie plants is thought to be responsible for distribution of plants that had the disease.  They recalled many of those plants that showed signs of the disease although they deny that the blight originated with their products, and state that blight is always in the soil.

There are three types of blight, the first two of which do not affect the fruit of the plant, other than lowering production.  The difference with late blight, is that the fruit very often rot before ripening and are not fit for consumption.

How to Prevent Tomato Blight From Affecting Next Year’s Crop

1. Plant from organic seed – plants are less likely to suffer from tomato blight when grown from seed.  This can be accomplished by starting seed inside 6 to 8 weeks before the last frost.  Planting from seed lessens the chances that your plants will be affected as they will not be exposed to the disease in garden center of greenhouse settings.
2. Use good garden hygiene – Particularly if you have infested plants, it is important to clean up the garden area well.  Do not allow plants to remain in the garden over the winter.  Clean up all leaves, tomatoes etc that may carry the disease.  These plants should be burned or placed out for pick-up. DO NOT place them on your compost pile.  This time of year, the compost pile is less likely to reach temperatures hot enough to kill off the spores.
3. Clean garden tools – Before putting tools away for the season, make sure that they are cleaned well.  Use a bleach solution to sterilize them.  Also make sure to throw away any pots the tomatoes came in that you suspect may have the blight.  Better safe than sorry.
4. Organic Fungicide – If you are comfortable using organic sprays on your plants, then by all means do so.  After a year of such severe blight, there is no reason to think that next year may not be very bad as well.
5. Plant rotation – You should always rotate plants from year to year, but this is a special case.  Plant tomatoes in a spot where they have not been planted in at least 3 years.  Also be careful about planting potatoes in the same area since tomato and potato blights are close cousins.

If you do have tomatoes this year that were not touched by blight, then do not let them go to waste.  Many large scale farms have lost their entire crop this year, and it stands to reason that tomato prices may skyrocket.