Tomatoes, Diseases of in Virginia
Bacterial Diseases: (Bacterial Canker, Bacterial Speck, Bacterial Spot, and Bacterial Wilt)
 | No economic thresholds have been established, but treatment is recommended
if initial symptoms of these diseases have been observed. Apply a fungicide
every 7 days if the threat of disease is present.
| The use of certified plants is critical, especially in areas where
bacterial disease is not yet established.
| A crop rotation of 2-3 years between tomato plantings may help manage the
causal agents of bacterial canker, speck and spot, but not bacterial wilt. | |
Late Blight:
| Blight forecasting systems can be very effective in identifying proper
timing of fungicide sprays.
| If cool, wet conditions prevail, a preventative fungicide application is
recommended every 7 days.
| Resistance management should be practiced when selecting a fungicide. | |
Leaf Spots: (Early Blight, Septoria Leaf Spot, Gray Leaf Spot)
| No economic thresholds have been established. Preventative fungicide
applications are the best means of leaf spot control, especially in areas
where this disease has been a problem.
| Good sanitation practices and crop rotation can help prevent leaf spot
establishment. | |
Wilts: (Fusarium Wilt and Verticillium Wilt)
| No effective chemical or biological controls are currently available.
| Cultural practices such as good sanitation and the use of resistant tomato
cultivars should be used if the disease has previously been a problem. Crop
rotations are not usually very effective given the persistence of the fungi
in the soil. | |
Gray mold, powdery mildew, Southern blight, timber rot (Sclerotinia) and post-harvest rots often show up under unusual conditions such as weather or result from poor cultural practices. Fruit rots (Pythium and Phytophthora) may also occur from time to time.
Consult the Commercial Vegetable Production Guide (456-420) for fungicide recommendations.
Reference(s):
