![]() ![]() Leaves may have become wet from condensation dripping from the tunnel roof, leaks in top of irrigation tubing or water depositing on leaves under high humidity. Following images taken on 17 June 2019 by Sandy Menasha, Vegetable Specialist Cornell Cooperative Extension of Suffolk County, document that early blight can occur in high tunnel tomatoes. The causal fungus can also cause symptoms on stems and fruit.īelow: Symptoms of early blight on fruit calyx and stem.īelow: One reason tomatoes are grown in high tunnels is to avoid diseases like early blight that are caused by pathogens that need leaves to be wet for several hours in order to infect. Sources of the pathogen are infested seed, debris from infected plants left in or on the soil (where it can survive at least 1 year), and spores from other affected plants dispersed typically short distances by wind, water, insects, or animals.īelow: Early blight symptoms first appear on older leaves near the base of the plant.īelow: Tomato leaves infected with early blight.īelow: Note the ‘target’ appearance of concentric rings. Young seedlings can be killed by stem lesions developing at their base. The causal fungal pathogen also produces symptoms on stems and fruit. Spots first appear on older leaves near the base of the plant. There are numerous cultural controls for this diseases, including removing diseased leaves, using clean straw or other mulch around the plants, using cages/other methods to keep plants off the ground, and spacing plants to allow for good air movement.Īpplying a copper-containing fungicide or chlorothalonil will also help prevent disease problems.The main symptom of early blight is round leaf spots with a characteristic target appearance due to the dark concentric rings that develop in most spots. Early Blight is very similar, except that instead of small black spots, you see 1/2″ lesions with concentric circles (bull’s eye) on the leaves. The disease moves up the plant as the summer progresses. The spots generally appear on the lowest leaves first, causing the leaves to turn yellow and die. If you click on the picture, you can clearly see the tiny black spots all over the leaves. Early Blight spores are not killed by soil-freeze. ![]() This tomato leaf shows classic symptoms of Septoria. The spores can overwinter in the soil if the plant sheds them and in unremoved or unnoticed plant debris. We haven’t seen any sign of them yet, but the symptoms and signs will probably start showing up after this warm, moist spell. Septoria Leaf Spot and Early Blight are two extremely common tomato diseases in this area. As the temperature climbs to 90 or hotter, it takes 12 hours of leaf wetness for infection to occur. At temperatures between 70 and 85, 6-9 hours of continuous leaf wetness will result in infection. The fungicides should be sprayed every 7-10 days when the conditions are right for infection. The best way to prevent the disease is to spray with either a copper-containing fungicide or myclobutanil (Immunox, but not Immunox Plus!). Last year I think we lost half of the grapes to this fungus. This morning I am seeing the first of the green grapes with the spots on them. Last week I saw this leaf with the characteristic lesions. I have already seen some indications of the Black Rot on the grapevines. The two diseases that I will be keeping a lookout for in the Demo Garden are Black Rot on the grapes and Septoria Leaf Spot/Early Blight on the tomatoes. Since our dry spell was broken last week with some damp weather, followed by quite a bit of rain, and now humidity, we are seeing great weather for disease problems! ![]()
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