2009-07-30 / News

Watch plants for signs of late blight

The Island Garden
By Roger Marshall

We’ve heard a lot about “Late Blight” during the last few weeks. While it can be a problem, there is no need to panic. First, understand that Late Blight has been around for hundreds of years. It is primarily a disease of tomato, potato and petunia plants, all of which belong to the same family.

The first incidence of Late Blight was spotted in mid-June on Long Island in a field of commercial potatoes and in a nearby home garden. These plants were removed and destroyed. The tomato plant grower also destroyed approximately one million dollars’ worth of plants that might have been exposed to Late Blight spores. Note that these plants were destroyed even though no signs were prevalent.

The symptoms of Late Blight are brown spots (lesions) on stems that gradually show a white fungal growth, olive-colored spots on the leaves with white fungal growth and tiny spots on tomatoes that eventually turn brown. Inspect your plants at least once a week for symptoms. If you see any of signs of disease or think you see signs of disease, contact your local extension agent (at URI). The only way to stop the spread of the disease once late blight has been found is to put the plants in a sealed bag before tossing them out. Do not compost them, as the spores are not destroyed in the heat of the compost pile.

Late Blight occurs when summers are wet, with limited sun. We’ve had the eighth wettest June on record and the wettest July since records began, so Late Blight might well occur. The best cure for the disease is heat, sunlight and dry weather, but as we are unlikely to see those conditions anytime soon, control it by spraying your potatoes, tomatoes and petunias with a fungicide, such as Daconil.

Now, let’s look at some good news. Potatoes, garlic and onions have grown huge with all the rain we’ve been having and are almost ready for harvesting. Dig potatoes and store them in a dark place. If you leave them in sunlight, they will turn green and become inedible. If your garlic has spathes (the green curly tops that contain the seed head), snip them off to make the plant put its energy into increasing the bulb size. You can cook the spathes, too, so you get an added bonus. As soon as the plants show signs of drying up, pull a head or two to see if they are fully ripe. If so, dig your garlic plants and store in a cool dry place to cure. After four weeks or so, they will have cured and can be stored for winter.

Onions are ready when the tops collapse and wither. That should be happening right about now. Like garlic, pull your onions and (if you’ve grown storage types) cure them for two to three weeks before storing. If you’ve grown large onions, such as Ailsa Craig, they must be used fairly quickly as they don’t store well. I use them to make a ton of onion soup that is then put in the freezer for winter lunches. Onion soup, French bread, a little grated parmesan cheese – yum!

Check cabbage, broccoli, caulifl ower and Brussel sprout plants for green caterpillars and dust them with Rotenone or BT to keep pests at bay. Harvest batches of parsley, dill, fennel, oregano and basil, and then chop and freeze in ice cube trays. When you need fresh herbs in winter, just drop a cube into your soup.

Oregano can easily be dried, too. Just hang a bunch in a sunny window until it is dried or put it in an oven with the pilot light on. When it is dried, strip the leaves, crush them and store them in a jar. Basil and oregano are nice on pizza or pasta. Basil tends to blacken when you store it in the freezer, so I like to make pesto with it. Garlic, basil, olive oil and pine nuts all go into the blender and when the mix is finely chopped, I add parmesan cheese. Ladle one meal-sized batch into sandwich bags and freeze. Pesto is good on toasted French bread (over tomatoes, too), or on hot or cold pasta.

Keep picking and keep hope. We’ll get some real summer sunshine soon – probably in October or November!

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