Tomato Bacterial Speck
Bacterial speck is a disease that can affect tomato plants. It can be spread easily and ruin entire crops of tomatoes.
Causes and Symptoms
Bacterial speck is caused by a bacterium known as pseudomonas syringae pv. tomato, which is spread by rains and cool damp conditions. If the seeds used for planting are infected or damaged, this bacterium can infect the resulting plant. It can affect both the tomato foliage and the fruit.
Bacterial speck lesions begin as small black spots, usually with a yellow or gold ring around them. Leaves infected with bacterial speck will curl up. On the fruit, bacterial speck forms small, raised lesions. They may resemble freckles or cause you to think your fruit has been bruised.
Treatments and Control
In order to treat bacterial speck on tomato plants and control the infection, it is important for the home gardener to know that the fruit lesions that can appear are only present at the surface level, and if the disease is not far advanced it is possible to scrape them off of the fruit. After this step is completed, the plants should be treated with copper preparations.
It is typical to recommend copper sprays to protect your tomato crop, because copper is effective at killing many organisms that can attack tomatoes, including fungi and bacteria. Though bacterial speck is a disease of bacterial, rather than fungal, origin, it may respond to copper fungicide sprays for tomatoes. These copper preparations should be sprayed on the plants at the very first sign of bacterial speck. It is recommended that spraying be repeated every seven days. This treatment will help to minimize crop losses from the disease.
There are several things that the home gardener can do to prevent and control bacterial speck. Only buy your seeds or transplanted tomatoes from reputable merchants. Make sure your seeds are free of disease. They should have been treated with hot water in order to eliminate bacteria.
You can also engage in rotating your crops and planting your tomatoes in a different spot every year, only returning to the same spot every four years or so in order to limit your plants’ exposure to the same plant debris. Remove weeds from the area you plan to use for planting your tomatoes. Since weeds can harbor the detrimental bacteria, their removal can again limit your plants’ exposure.
It is important to make sure your plants have enough exposure to the air in order to prevent bacterial speck. This requires proper staking and spacing between them.
It is also possible to purchase varieties of tomatoes that have been grown to resist the development of bacterial speck and other diseases. Using these varieties will also prevent the spread of bacterial speck.