Tomato plant problem
I have 3 varieties of tomato plants- Better Boy, Celebrity and Roma. All we're doing very well until about 2 weeks ago. Now the bottom branches and leaves are turning yellow and dieing. Attached are 2 pictures- Celebrity and Roma. The plant tops are still growing but to keep them manageable, I do snip off the new shoots. What is happening to the plants? Is this a result of the high heat and humidity we have been having? I mulch with newspaper under straw and try to maintain moisture as well as using Miracle-Gro roughly every 3 weeks. The fruit coming off the plants are still very good and are still growing but the plants look horrible. What caused that and what can be done to prevent it? Thank you
Carroll County Maryland
It is normal for the bottom leaves to yellow and drop as the plant ages.
If you are noticing browning and leaf spotting, tomatoes can be susceptible to several foliar diseases. Two common foliar diseases are early blight and septoria. They can also co-occur on the same plant. Humidity and moisture are ideal for development of the diseases but it does not matter which disease it is because the management is the same.
Select disease resistant varieties, 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 an organic fungicide (fixed copper) early in the season to lessen the spread of the disease. Fungicide treatments can help to protect new or un-infected foliage, they are not curatives. It is too late to spray. Remove infected plant material at the end of the season.
There is nothing you can do at this point to fix the problem. Pick off the tomatoes that are already showing color. You can keep them on a counter top inside to let them finish ripening. In the future, consider choosing tomato varieties that have disease resistance. Cornell University is a good source for suggested varieties. http://vegetablemdonline.ppath.cornell.edu/Tables/TableList.htm
See our website for more information and photos on early blight http://extension.umd.edu/growit/early-blight-vegetables and