I just don't know what is happening to my poor tomatoes! I have four tomatoes...
I just don't know what is happening to my poor tomatoes! I have four tomatoes planted in Earth Boxes in my Baltimore city driveway. I bought them from the JFX farmers market back in May- they are all indeterminate varieties (clearly a mistake that I will not repeat next year because I'm finding them very hard to manage). Once it got nice and warm in June, they all exploded and each Earth Box was taking more than 4 gallons a day. They were lush and happy. One of the plants (an Italian plum variety-on left on the photo) is doing just fine, but my other three plants (one of which even shares the same Earth box with the plum) are in various stages of dying- the problem began just as each plant had a good amount of green fruit. I think they may have aphids, but the tiny bugs don't seem to look the pictures I see online. They are reddish brown and smaller than a pinhead- I can only see them moving if I hold a leaf right up to my eye. I don't know though- the three plants are affected by seemingly different problems, despite the fact that all four have these tiny bugs. The attached pictures are really the best I can do- basically, one of the plants is slowly losing each branch from the bottom up- they get yellow and die, but there is still new healthy growth up top and a few tomatoes are ripening though most of them split and rot on the vine. Another plant seems to be getting yellow and brown spots on its leaves uniformly throughout. The last plant seems to be affected by a combination of the two problems previously mentioned (this plant is on farthest right in the photo). I don't know if this is relevant, but I have been trimming them quite a lot by cutting all of the "suckers" off in an attempt to keep them contained. Also, my Earth Boxes contain a potting mix, dolomite lime, and fertilizer strip exactly as recommended by the company.
The tomatoes in the photo look like they were subject to some possible foliar diseases and spider mite damage.
Spider mites like hot dry conditions. There are horticultural oil and insecticidal soap sprays that control spider mites but spraying in hot weather can cause more damage to the foliage. At this point it may be helpful to hose the plants and leaf undersides early in the morning so they will be dry by evening. Next season monitor early and you can control if need be in their early stages. See our website http://extension.umd.edu/growit/insects/spider-mite
Foliar diseases include include early blight, Septoria, and gray leaf spot. All produce 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
Too much moisture can cause yellowing. However, it is normal for bottom leaves to yellow and drop as the plant ages. Too much moisture can also cause cracks on ripe fruit. You can pick your fruit at the blush stage and they will ripen on your counter. Continue to prune suckers.
Thank you for your help! After looking at the spider mite page you suggested and googling more pictures, I think they definitely have spider mites, complete with little webs- blech!
One more question about the foliar diseases- since even the saddest plant has healthy new foliage at the top, should I cut off the rest of the infected and dead foliage in an attempt to remove the fungus, or is that futile at this point?
You can remove dead and infected foliage to try and lessen the spread.