cause of yellow leaves on tomato plants
Causes of Yellowing Leaves. Common causes of yellow leaves on tomatoes include cool soil, age-related death of the lower leaves and a myriad of nutritional deficiencies including nitrogen, boron, potassium, iron and magnesium. Leaves may also yellow when affected by fusarium wilt, bacterial wilt or verticillium wilt.
Some tomato plant leaves yellow due to a lack of sunlight on mature plants. When the plants become large, bushy, and heavy with fruit, the top portions of the plant can block the lower portions from getting sunlight. This can cause the leaves to yellow, and is really nothing to worry about.
The saliva causes yellowing tomato plant leaves, and often makes the veins turn purplish. The stems of the plant will take on a zig-zag appearance. Once the saliva has taken over the tomato plant, it is difficult to save. For best results, dust the leaves with sulfur as soon as you notice symptoms.
If you notice yellow leaves in other areas of the tomato plant, or the yellowing at the bottom is spreading upward, this could be a sign of disease, such as curly top virus (usually curly top virus will show signs of yellowing leaves that are curling up as well), Ringtop Virus, or other diseases.
Early Blight Alternaria â Treatment For Tomato Plant Leaf Spots And Yellow Leaves. If you have noticed tomato leaf spots and the lower leaves turning yellow, you may have tomato early blight alternaria. This tomato disease causes damage to the leaves, stems and even the fruit of the plant. Keep reading to learn more about what causes tomato early blight alternaria and how to treat leaf spot.