Tomatoes are maturing in our gardens this week accompanied as always with fungus, bacteria and insect pests. In his article last week, our local extension agent James Shannon tackled some of the obstacles faced in getting our tomatoes to harvest. Thanks and we will stay tuned for other tomato topics!
Among the awful things that happen to tomato plants this time of year is bacterial speck and bacterial spot. A call came in to the extension office this week wondering how to handle this problem.
Bacterial speck and bacterial spot are very similar. Both infect cellular structures leaving angular edges on the dark brown to black lesions. Bacterial speck lesions develop a yellow halo or dark green halo. Bacterial spot tends to form dark streaks with a shot hole appearance as the lesions coalesce and the dead foliage may remain on the plant. Bacterial spot on the fruit appear as raised blisters that become brown and scabby. Bacterial speck on the fruit are dark lesions.
Some bacterial speck and spot have developed a resistance to copper fungicides, but hopefully ours have not. I am spraying weekly with copper fungicide to combat bacterial problems along with chlorothalonil (Daconil) for fungus, such as early blight. Pick off infected leaves as much as you can to reduce the numbers of pathogens and rotate your tomato and pepper plants with other plants next year.
If you would like more information about Tomato diseases, see “Common Diseases of Tomatoes” Publication No. P3175 which can be found at msstate.edu. Good luck and have a happy week in your garden!
Do you have a gardening question? Call the Pontotoc Extension Service at 662-489-3911 and ask to leave a question for the Master Gardeners. Pontotoc County Master Gardeners are trained volunteers who help the MSU Extension Service and serve the people of Pontotoc County.