Beware of late blight!

Friday July 27, 2012

Although showers have been hit or miss, depending upon where you live, we have finally begun to get a little relief from this summer's drought.

However, as mentioned a few weeks ago, when moist weather returns there is also a risk of late blight infections on tomatoes and potatoes. It looks like my worst fears are becoming reality.

I've been monitoring the pro gress of late blight via contact with plant pathologists at UMass and also by checking USDA's USA Blight website ( node/29). As of this week, late blight has been found nearby in Litchfield County in Connecticut, Dutchess County in New York, and Franklin County. The USDA site also reported a "confirmed" occurrence in Berk shire County, but my contacts at UMass have not yet confirmed this.

Current stormy conditions favor occurrence of late blight on unprotected plants. Therefore, it is wise to protect plants now with weekly applications of an organic product containing copper sulfate or bacillus subtilis.

If you see late blight infections (check the USDA site for pictures of late blight) on tomatoes and/or potatoes, immediately pull up and destroy the plants. Symptoms on tomatoes include large brown lesions on the young leaves at the top of plants, dark brown stem lesions, and brown rough lesions on tomato fruit. Often, white fuzzy growth may be seen on leaf and stem lesions. Burying the plants is an option for tomatoes, but potato plants should be put in plastic garbage bags for disposal.

Daily monitoring of tomato and potato plants should be at the top of your "to do" list but here are other gardening tasks:

  • Cut long flowering stems of baby's breath, bachelor button, butterfly weed, delphinium, goldenrod, lavender, Queen Anne's lace, salvia, strawflower, yarrow, and zinnia for drying. Strip away most of the leaves along the stems, tie each type of flower in small bunches of five stems, and hang these upside down in a dark, dry, and airy location for about two weeks or until the stems are dry and brittle.
  • Replace fading annuals in containers and in flower beds with new plants. Garden centers still have bedding plants for sale but at much reduced prices. Sort through the plants carefully as some may be a little leggy. However, if the stems are cut back a little, the plants will be useable and attractive. Give the plants a boost by applying dried blood or liquid seaweed after planting.
  • Sow seeds of biennials, such as foxglove, pansy, honesty, sweet William, Canterbury bells, and forget-me-not, in a partially shaded seed bed or in flower borders, where they are intended to grow. If starting biennials in a seed bed, wait until they are well developed and then dig and move them to their final destination. This can be done in early fall. The plants may need winter protection. So, cover them with pine boughs or other loose mulch once the ground is frozen.
  • Pull up spent peas, bolted lettuce and spinach, and any other crops that are no longer yielding any harvestable vegetables. There's still time to plant bush beans, leafy greens, and root crops such as radishes and turnips.

I'm a big fan of buckwheat. I love that little rascal in the Our Gang comedies. I also love buckwheat pancakes and bread, but most of all I love buckwheat as a summer cover crop in our vegetable garden.

Although we are planting some late crops to fill in vacant spaces, there will still be open sections in the garden. Over these areas, we'll scatter buckwheat seeds. Buck wheat seeds sprout and grow quick ly, shading the soil and inhibiting development of weeds. Once the buckwheat plants begin to flower, they'll be cut down and tilled into the soil, contributing a small, but valuable amount of organic matter. In mid-September, a winter cover crop or winter rye can be planted where the buckwheat grew.


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