There is a fungus among us: advice for vegetable gardens

Gardeners have been seeing alerts in the media, on websites and in newsletters regarding some particularly aggressive disease problems which may be appearing in garden vegetables such as potatoes, tomatoes and cucumbers. In addition they may be observing wilted squash and cucumber, and eggplant vines, and other symptoms which seem to be threatening the success of the garden harvest for which they had great hopes.

There is a tendency to overreact and spray what I call “pantry pesticides” such as baking soda, peroxide, garlic juice, bleach, vinegar, dish soap or anything that seems like it might be strong enough to kill pests and bring these crops back to good health. Likewise whatever insecticide or fungicide happens to be in the garage might seem like a good bet. Don’t do any of these things. Find out what your problems are.

Right now, wilted zucchini or squash may be squash vine borer, an insect that is boring into the stem. Eggplant may be wilting due to Verticillium wilt. Cucumbers with wilted runners are probably suffering from bacterial wilt, a disease spread by cucumber beetles. There are plenty of university websites that will give you recommendations for cultural control. Chemical control recommendations are harder to come by because product offerings change rapidly and universities do not want to endorse products (the following information – inclusion or exclusion of products—is not an endorsement). However, on tomatoes, leaf blights, including early blight, Septoria leaf spot and late blight are best controlled with the use of preventative fungicides containing chlorothalonil. These are not considered to be “organic” products, but may be used safely. Two brands for gardeners that can be used close to harvest are Ortho-Max Garden Fungicide and Bonide Funginol. These products will also help prevent downy mildew and powdery mildew on cucumbers and other vine crops. Bear in mind two things:

  • Disease control is preventative, not curative, so gardeners must apply as directed and continue when conditions are favorable for disease spread and development
  • All pesticides must be used according to label directions. Cover any part of your body that might come in contact with the material and do not allow drift to get into your eyes.

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