Tuesday, July 7, 2009
Late tomato blight is making an early appearance, according to many agricultural researchers, including Penn State. The blight is fatal to both tomatoes and potatoes two closely related botanical cousins. The blight will cause the plants to blacken and die within a short period of time, in most cases less than week.
It appears that infected tomato plants have been discovered throughout much of the Eastern United States, including Pennsylvania and New York. The blight has been discovered in tomato plants which were sold by a southern grower to some big chain stores, called “Big Box” stores such as Wal-Mart, Lowes, Home Depot and Kmart.
That could mean many home gardeners, including first timers, could have infected plants, which need to be immediately destroyed. The blight organism, the same one which caused the great Irish Potato Famine, spreads like wildfire and is carried by the wind. It can easily spread from neighbor to neighbor and places such community garden in danger. It also has the commercial growers nervous.
If you bought plants from a smaller grower or grew themselves, your chances are a little better. Another good reason to choose heirlooms, save your seeds, and grow your own seedlings.
The blight is making an appearance early and has been fueled by our wet and cool weather this spring and early summer. Conditions are ripe for a serious disease outbreak. Once the blight has been discovered , pull the plants, Do not add to the compost pile. Burn them or enclosed in a plastic bag and let them fry in the sun for several days, then trash them. Again, never compost these sick plants, the risk of spores remaining in the compost is too high to take the chance.
There are some commercial sprays which are available to use to prevent or lessen the blight's attack. These remain somewhat controversial as to their effectiveness. There are other options, there is a baking soda spray from Cornell University, this is a three page article and the spray formula is near the end.
Another homemade option is compost tea. I would start using this as soon as possible. I have tried it and it works but it is a constant challenge. Be sure to remove any infected leaves before you start spraying, but it won't hurt one bit to start spraying now even if the plants appear healthy. There is no reason to panic, just get started now and save that crop of tomatoes or potatoes.
It is also important to make sure the tomatoes are staked and not crowded. A good layer of organic mulch can also help.
Clicking on any of the links (underlined words) will take you to additional information about this serious problem facing all gardeners. And note, the blight has been a problem for a long time; it is not harmful to humans.
Pictured: Well, the heirloom tomatoes here look good so far, have a few about the size of bunker marbles, and, the potatoes seem okay to date, but I'll be spraying compost tea this weekend.
Blogs to read that are informative and just good reading:
On Your Way to the Top
New York's Southern Tier
Urban Veggie Garden