Protect your Harvest

Maybe it’s the wet weather.  Maybe it’s nature throwing all those first time vegetable gardeners in PA a curve ball.  Whatever the reason,  late blight is here early this year and if you want to insure your harvest of tomatoes or potatoes, you’ll want to take preventative steps.

Late blight is a fungus that usually occurs at the end of the growing season.   It is the same fungus that caused the Irish potato famine in the 1850’s.  It’s not new to Pennsylvania.  What is new is the timing.

Having to deal with it this early could be a real problem for commercial growers and home gardeners. Since it is already here, the best precaution is to apply protectant fungicides until the end of the growing season.

For home gardeners, seek the active ingredient Chlorthalonil (labeled as Fungonil, Daconil and other trade names).
Apply this every 7-10 days covering the plant and fruit completely. It will leave a white haze on the leaves and fruit that washes off.  It is safe to apply up to the day before harvest.

For those that walk the organic path, they can either wait for their plants to be infected then destroy them or apply what is known as a fixed copper (there are many on the market)every 7-10 days. Most commercial organic growers use ‘Champ’
copper formulation. I don’t like to apply these coppers the week of picking to avoid that penny in the mouth taste.

There is huge question regarding the efficacy of 2 other remedies (actually preventatives) available to home gardeners: Neem oil and Compost / Vermiculture teas. Raw Neem oil may be worth trying, but it is very difficult to find truly
raw Neem oil. Many of my Amish clients in Lancaster swear by vermiculture fermentation extracts, but no one has tested it against Late blight.

Once your plants get it they are goners, there are no treatments to control this disease in infected plants. That makes the application of protectants paramount.

How can you tell if your garden has been affected? Your  plants will get blotchy lesions on the leaves and start to look burned up. If you look at a late blighted patch as the sun rises, it appears silvery. This silvery appearance is massive numbers of spores
maturing and taking to the wind and rain. Fruit appear to be hit with axel grease.

The only solution to blighted plants is to destroy them. I recommend cutting them off at the base, allowing the plants to dry down for several days, then burning the dry tissue. Do not compost late blighted plants as it is very difficult to get compost hot enough to kill the spores. We let them dry first to keep from spreading the disease around as you drag the live diseased plants through the garden.

Take precautions.  The good news is,  if you find blight, and thoroughly clean up all the diseased plants, you’ll have a fighting chance next year.