I have an issue in the DWC portion of my AP system - 200 gallon with 4 - 3x3 media beds and 1 - 12x4 DWC trough. The lettuce is getting the yellow/brown discoloration on some of the mature leaves. See attached pictures. Just trying to properly identify it and come up with a good organic AP remedy. Thanks - Daryl
Downy mildew can ruin your plant in a matter of days or weeks. First of all you need to remove all infected plants from your garden. Try to eliminate moisture and humidity around the plants. You can use downy mildew by spraying the infected plants with a fungicide. But sometimes Downy mildew is often the most challenging, so try to consult pest control services who will use low-input pesticide applications.