tomato leaf disease

Asked June 14, 2013, 11:55 AM EDT

The leaves of my tomato plant have what looks like large rust spots on them. I've grown tomatoes a long time and I've never seen this problem before. I sprayed it with a pyrethrin-based product and the new top leaves look like they're okay. Should I trim off all the damaged leaves and see if the top still keeps growing? I also noticed that the green developing fruit now has tiny round black spots (like roach feces) and thought maybe it was caterpillar feces but they don't knock off the fruit and it would be a very small caterpillar and the fruit developed to about the size of a 50 cent piece and hasn't grown any bigger in a couple of weeks. If you need any more info, let me know.

Miller County Missouri

6 Responses

Pyrethrin products are insecticides and will probably not help the disease issues that you have. The symptoms you describe sound like 2 separate diseases.

The leaf condition sounds like early blight or septoria leaf spot. These are fungal diseases and you can try a fungicide containing captan. like many fungal diseases, the extra moisture this spring has made them worse. The later control measures are taken the less effective they are.

Early Blight pictures:
http://www.extension.umn.edu/yardandgarden/ygbriefs/p-earlyblight-potato.html

Septoria leaf spot pictures:
http://www.ipm.iastate.edu/ipm/info/plant-diseases/septoria-leaf-spot

control measures: http://ipm.missouri.edu/MEG/2011/5/Preventing-Foliar-Tomato-Blights/

Early blight can also cause lesions on the fruit. But, it also can be Bacterial spot.

Description: http://extension.missouri.edu/p/g6203

Pictures:
http://vegetablemdonline.ppath.cornell.edu/factsheets/Tomato_Bacterial.htm#Click

If still uncertain call or visit your local extension office:
Miller County
134 Second Street
Tuscumbia, MO 65082
Phone: 573-369-2394
Fax: 573-369-2394
Email: Millerco@missouri.edu
Website: http://extension.missouri.edu/miller

Thank you for the information I asked for. It was very helpful. In closer inspection of the leaves, I believe it is, indeed, a leaf spot fungus. What is best to sterilize my tools? 70% alcohol or bleach or something else? If bleach, what ratio? I have to go shopping for a fungicide and would like to know what brands (or ingredients) would be best for tomatoes with this problem. I have a very small home garden so prefer a product in a spray bottle, not a liquid that needs to be mixed w/water. Thank you so much for your helpful information.

Also, I have a drip irrigation system so overhead watering isn't in the equation.

50/50 Bleach to sanitize your tools. Captan is the fungicide ingredient of choice. Most of the fruit & garden didease control products will provide some help. Many are RTU, Readt To Use.

I have been doing some research online and found an interesting product called Serenade Garden. What are your thoughts on this. And thank you for the info about what RTU means. I saw it in several places in my perusing. Thanks again for your time and especially your quick replies.

I have no data on that product or its active ingredient. I still recommend looking for the active ingredient - Captan. Serenade Garden only claims that it will suppress the diseases that we suspect that you have.