What is happening to the tomatoes this year?
My customer's tomatoes (several different varieties) are not growing or ripening. They are basically stopping their growth cycle, almost wilting and falling over. None of the various varieties are looking healthy with the leaves turning brown and curling. Will you take a look at the photos and help me explain what might be going on? And also, if there is any hope of reviving them this year and solutions for next year's crops.
This looks like Early Blight to me, which is caused by the fungal pathogen Alternaria solani. Diagnosing tomato diseases can be challenging from pictures, but that is my best guess. I also saw the pictures that you sent through your local extension office. Early blight is polycyclic, which means that it will continue to produce spores and infect healthy tissue when conditions are right for spore formation. Leaf wetness from dew, rain, or overhead irrigation will stimulate sporulation and further spread of the disease. Anything that you can do to reduce leaf wetness will slow its progression. Treating with a fungicide that is labelled for use in the home garden against early blight will also slow the spread, but will not cure the infection.
For next year, if they plan to grow tomatoes or potatoes, it will be very important to remove and destroy all of the infected plant residue (whole plants, fallen fruits, leaves, etc), because it will serve as inoculum for next year's crop. Inspecting the surrounding natural areas for solanaceous weeds (e.g. nightshades) and removing them will also prevent the return of this disease next year. I would also recommend choosing Early Blight resistant varieties for next year's garden.