Hi I believe my tomato is suffering from wilt. It's a big boy burped plant...
The photo of the tomato shows the foliage may be affected by early blight, a fungal disease. You may also want to look for spider mites, a sucking insect. We cannot see a wilt disease. Some reasons for wilt include overwatering, underwatering, are they located in the vicinity of a black walnut tree, and possible wilt diseases. See our publication on tomatoes for symptoms and causes
Early blight 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. It is too late to spray this season. Fungicide treatments can help to protect new or un-infected foliage they are not curatives. See our website for more information on management of the diseases. http://extension.umd.edu/learn/early-blight-tomato
See information on spider mites http://extension.umd.edu/growit/insects/spider-mite