What is causing this damage to my tomato plant leaves? It occurs on the tips...

Asked July 30, 2014, 2:19 PM EDT

What is causing this damage to my tomato plant leaves? It occurs on the tips and or the side edges of the leaves. Spider mites have been an ongoing problem. I have also seen leafhoppers and whiteflies. Is this a disease, insect damage, damage from insecticidal soap and or horticultural oil used to treat spider mites, or something else? The plants are beginning to look tired and the new green tomatoes no not seem to be developing. I was originally removing the leaves it appeared on, but it is beginning to appear on too many leaves. If it is a disease can I prevent it from spreading by spraying with a liquid copper fungicide/bactericide? Do I need to remove all of the infected leaves prior to treating? Thank you in advance for any advice you can give me, Jackie

Montgomery County Maryland

1 Response

The tomato foliage looks like it may have been subject to early blight, a fungal disease. This produces spots or lesions on leaves, start at the bottom of the plant and progress through the season if conditions are right, to defoliate tomato plants (spotting, yellowing, dying.)
You can remove the lower leaves to slow the upward spread of the disease, keep plants well mulched to minimize soil splashing, water at the base of the plants, provide adequate spacing and spray with a copper fungicide (early in the season) to lessen spread of the disease. Fungicide treatments can help to protect new or un-infected foliage they are not curatives. Fungicides should be used as a last resort for persistent vegetables diseases. See our website for more information on management of the disease. http://extension.umd.edu/learn/early-blight-tomato
Also, see the publication for more information on use of Organic Pesticides