Greenwood County • Agriculture and Natural Resources Extension Agent Tomato Harvest: Fungal Diseases
Ant i cipating the upcoming tomato harvest, gardeners need to stay on the lookout for a pair of fungi that threaten to rob the bounty. Warm, humid weather and heavy rainfall favor the development of Septoria leaf spot and early blight in tomatoes. These are both environmental conditions we have been seeing much of in recent weeks.
Septoria leaf spot appears initially as small, water-soaked spots on the lower leaves. The centers of the spots turn light tan or gray, while the margins remain dark. Dark-colored fungal fruiting structures form in the spots, which are typically smaller and more numerous than early blight spots. Early blight symptoms appear as irregular, brown lesions or spots on the leaves up to one-half inch in diameter.
The dark concentric rings in the lesions give the spots a target-like appearance. It’s a rather distinguishing symptom to identify the disease. Several lesions can merge together and cause the leaf to yellow, dry up and drop prematurely. Leaf drop reduces the plant’s ability to photosynthesize, thus reducing the energy and vigor of the plant. It can also expose fruit to an increased risk of sunscald. Early blight lesions can develop on the stem and fruit, as well. Septoria leaf spot tends to be more common than early blight.
If you are interested in more information about diagnosing and treating these diseases, you can do a internet search for K-State Research and Extension Early Blight and Septoria Leaf Spot, or stop by the office and we would be happy to print a copy for you.
Information comes from K-State horticulture expert, Cynthia Domenghini.
For more information regarding upcoming programs, Agriculture and Natural Resources, 4-H Youth Development, or K-State Research and Extension call the office at 620-583-7455, email me, Ben Sims, at [email protected], or stop by the office which is located inside the courthouse. Be sure to follow K-State Research and Extension- Greenwood County on Facebook for the most up-to-date information on Extension education programs and the Greenwood County 4-H program.
