Out in the vegetable garden, foliage diseases, especially on tomatoes, are at very high levels. One particular is a disease called Late Blight. Late Blight favors these wet conditions. Nearly all of the tomato diseases start at the soil line or interior of the tomato plants. If unchecked the disease moves up and outward from there, eventually leaving a tomato plant with tufts of leaves at the ends of the branches and fruits exposed to the sun. The hybrid varieties do much better as disease resistance has been bred into the plant. It still may get the foliage diseases, but tolerates the problem much better. Heirloom and antique varieties have limited or no disease resistance, so in a year like we are experiencing, foliage disease can be very devastating.
Leaf diseases can affect snap beans and vine crops too, yet the one that really impacts the garden are those on the tomatoes. Disease management includes not working the vegetable while the foliage is wet to prevent spreading the disease, proper spacing to allow plants to dry out quickly after a rain and watering the garden so foliage is dry by late afternoon. Any spray treatments done are going to be preventative, which is not where we are now. Any treatments now will help to slow the spread, but any leaves already there with disease will die.
It is impractical to attempt to remove the damaged leaves and if attempted would likely result in spreading the disease even more as disease spores would be scattered in the air as the leaves are removed. This is going to be a very challenging year for the vegetable garden.
Questions about your yard or garden? The Kendall County Master Gardener Help Desk is open for the season. Trained volunteers can answer your tree, garden, lawn and other horticulture questions from 9 a.m. to 12:30 p.m. Monday through Friday at 630-553-5823.Richard Hentschel is a Horticulture Extension Educator with University of Illinois Extension, serving DuPage, Kane and Kendall counties. Stay tuned to more garden and yard updates with "This Week in the Idea Garden" videos on Facebook at facebook.com/extensiondkk.