Is This What's Wrong With Your Tomato Plant?

Client's Request: Client is growing tomatoes in a community garden. Several of the client's tomato plants are now droopy, appear diseased on the stems and leaves, and not performing as expected. Client dropped off a sample of the tomato plant (leaf and stem) at a Farmers' Market Master Gardener Help Desk. It was then delivered to the MGCC Pleasant Hill office for a Help Desk analysis of the problem (s?) and recommendations of what to do next.

 

 

 

 

 

 

 

 

 

 

 

 

MGCC Help Desk Response and Advice:  We were able to determine what was going on with your tomato sample by viewing it under our microscope. We found spider mite infestations, but that is secondary to what is actually going on with the plant. We believe that the tomato plant is suffering from "pith necrosis". While Master Gardeners have seen some previous evidence of this tomato disease, it is so far rarely seen in California, and UC does not have very much information or recommendation on the disease. However, Ohio State University has a Fact Sheet that provides information on the disease and its management. http://u.osu.edu/vegetablediseasefacts/tomato-diseases/tomato-pith-necrosis/. From our reading of the Fact Sheet, it doesn't appear that there is much you can do to manage the disease at this point in the tomato growing season, but you should consider your cultural practices before planting in the same plot next year (e.g., crop rotation, fertilization, etc.). The OSU Fact provides the best guidance we have at this time.

You will also want to read up on spider mites and keep an eye out in the garden for other plants which may be affected. Spider mites are difficult to control but it would be worth making the effort because you are in a community garden situation. UC does provide information on spider mites identification and control on this rather commonly found pest. Take a look at the section on cultural control in particular as spider mites thrive in dusty conditions so irrigation and dust control in the garden is especially important.  http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7405.html 

Thanks for contacting us and providing the sample.

Help Desk of the Master Gardeners of Contra Costa County

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Note: The  Master Gardeners of Contra Costa's Help Desk is available year-round to answer your gardening questions.  Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA  94523. We can also be reached via telephone:  (925) 646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/