Tomatoes are subject to an enormous array of issues. Fortunately, this excellent disease ID key for tomatoes from Cornell University Department of Plant Pathology has everything that a local gardener needs to make a close-up examination of their plants and determine what is going on. You can follow links for each individual disease for more photos of the symptoms. We are seeing a lot of issues related to recent heavy rains and splashing of water on foliage, which is very conducive to fungal disease.

General care of tomatoes begins with soil preparation as they are big users of nutrition. The soil should be light and fertile and preferably organic. Add compost and aged cow manure into the vegetable garden every season (either in fall or spring). Full sun (6+ hours direct sun) is also important for healthy plants, both for photosynthesis and keeping the soil and roots warm. A compact determinate tomato plant will do well in a container but must have great soil, plenty of sun, good drainage and regular, morning water. Feed your tomatoes every two to three weeks with a dilute solution of fish emulsion or an organic tomato fertilizer.

Water in the morning so that the plant has a full day to use the water while photosynthesizing. (Night watering will evaporate in hot weather before a plant can make use of it.) Take care not to splash the bottom leaves with water or fungal infections are given an opportunity to take hold.

You can learn more in our guides Growing Healthy Tomatoes and Tempting Tomatoes.

Courtesy of NYBG Plant Information