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Fusarium wilt | Verticillium wilt | Tomato Spotted Wilt Virus | Sunscald | Leaf roll Tomato Yellow Leaf Curl virus | Soil rot | Blossom end rot | Buckeye Rot | |
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Most Disease problems can be greatly Reduced with a combination of practices that include:
1. ] Purchase vigorous, healthy plants from a reputable supplier. Tomatoes, being susceptible to diseases, viruses and insects, some varieties have been bred or hybridized to be resistant to certain pests.
Resistance to these pests is usually
listed on the plant label using the following abbreviations: |
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2.] Crop Rotation in your garden planting area 3.] Remove and destroy all plant refuse in the fall and use deep cultivation to bury any remaining refuse. 4.] Do not place diseased plants in the compost heap, as this will only serve to carry bacterial or fungal infestation into the next growing season. 5.] Avoid over watering . Use surface watering methods. Do not handle plants when the vines are wet. 6.] Weeds compete with vegetables for soil moisture and nutrients and also serve as hosts for insects and disease carrying bacteria and fungus. Control weeds in and around the garden . 7.] Control insect pests such as aphids, which are known to transmit diseases from plant to plant. 8.] Use
plastic 9.] Choose a sunny location for your tomatoes. Leaf disease problems are much less likely to occur in a sunny location than in a shady one. 10.] Apply recommended fungicides according to label directions at the first sign of leaf spot diseases 11.] Remove abnormal or unhealthy appearing plants as soon as they are observed. To reduce the spread of suspected diseases wash hands and tools with a mild detergent after handling suspect plants.
See:
A Colour Atlas of Tomato Diseases: Observation, Identification and Control
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or
The earliest
signs of Fusarium Wilt in Tomato plants is the drooping and subsequent yellowing of
the lower leaves on one stem. These symptoms may appear on only one side
of the plant. Yellowing and wilting of the leaves occurs, and
the plants may eventually die. If the stem is cut , plant tissues under the surface are
frequently discolored brown.
Favored by soil temperatures around 80 F, and a low soil pH, Fusarium wilt is more common in southern latitudes. Verticillium wilt
, which is indistinguishable to the eye is more prevalent in Northern
regions.
Verticillium wilt closely resembles Fusarium wilt, only a laboratory diagnosis can sufficiently distinguish between the two. Verticillium wilt starts with a general or blotchy yellowing of the lower leaves and a wilting of younger shoots when exposed to direct sunlight. Initially, the wilted shoots will recover over night.
The leaf veins will brown, followed by
the shoots browning and lower leaf drop. Leaves higher up turn a
dull green in color and the edges curl upwards. Plants are stunted and
defoliated with only the growing tips remaining green. The fruits are
small and sunscald easily. The branches
tend to be less erect than those of healthy plants, giving
Verticillium-infected plants a prostrate appearance. When the
stem is cut open, the plant tissues
are generally a murky brownish near the base of the plant.
- Remove and destroy all wilted plants and all
debris of tomato and other susceptible crops at the end of the
growing season {Do not put them in the compost heap, this will only
serve to perpetuate the disease}.
- Other susceptible crops are peppers , eggplants, potatoes, raspberries and strawberries
- Crop Rotation - Rotate in a four year cycle with non susceptible crops, the fungi that causes wilt survive for many years in the soil and Verticillium as well as Fusarium fungus will attack many other plants.
- Use wilt resistant varieties -resistant tomato varieties are labeled V (for Verticillium) and F (for Fusarium). These disease resistance designations are shown in reputable seed catalogs both paper and online.
| Spotted wilt is caused by the tomato spotted wilt virus {TSWV} - no rocket science there. Spotted Wilt or TSW will greatly reduce the quantity and quality of the harvest. More than 150 plants are effected by this virus. Pepper ,lettuce, eggplant, cauliflower, celery, spinach, pea, dahlia, sweet pea, nasturtium, chickweed, poppy, lily, orchid, chrysanthemum, cineraria, mallow, etc... . Thrips transmit this virus. They acquire TSWV as larvae and later transmit it . Spotted Wilt symptoms vary widely, The first symptoms are orange flecks or a bronzed appearance of young leaves. Leaf spots may appear target-like as in early blight. Older leaves turn brown, droop and wither. Younger shoots may develop dark streaks, dieing back not the ends . Raised yellowish spots develop on green fruits. As the tomatoes ripen, these spots become more prevalent with rings of yellow or brown alternating with green and later pink or red. Similar diseases have slightly different symptoms. Vascular wilts do not have the orange spots on the leaves, or circular bulls eye spots on the fruits. Avoid proximity to plants {Weeds are plants too} that can serve as hosts for this virus. It is important to control weeds, especially chickweed and which serves as a place for the virus to overwinter. In the spring, these weeds become a major source of the virus. Do not grow tomatoes near lilies or dahlias or other ornamentals either in or outdoors. Reflective Mulch
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will reduce, but not
eliminate losses from Tomato spotted Wilt . Management of
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Sunscald Sunscald develops on the side of fruits suddenly exposed to the direct sun, first appearing as a light colored spot on green fruits. It's not really a disease and can not be transmitted from plant to plant, it's basically a sun burned tomato. This spot develops into a blister, and later becomes sunken and whitish with a paper-like surface. Sunscald will occur frequently after pruning of tomato plants. Once Sunscalded a tomato can not be "repaired" , but its progression can be slowed. You can leave exposed fruit on the vine and cover it with lightweight screen, shade cloth, or straw to protect if from further damage. You can also harvest them and allow them to finish ripening on a windowsill or kitchen counter. If Sucscald is a problem in your garden ther are a number of routes you can take.
•Don’t over-prune tomato plants, this exposes previously shaded
fruits and remaining foliage. Tomatoes with sunscald are okay to eat, so long as Black mold hasn't set in , simply slice off the effected portion
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| Leaf roll
Leaf Roll generally develops in rainy periods. The lower leaves roll upward until the edges touch and become thick and leathery . Leaf roll is predominant in cool wet weather, excessive fertilizer, and pruning are contributory factors. Leaf Roll has no serious effect on plant growth or yield. Other causes of stress on a tomato plant that can cause leaf roll are
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Tomato Yellow Leaf Curl
virus. Tomato Yellow Leaf Curl virus is transmitted by sucking insects - whitefly in particular. It is not transmitted through seed or by external mechanical means. Infected plants will show stunted and erect growth. Early infection can lead to a severe stunting of the plants growth with little or no yield at all. Leaves are smaller than average and curl upward with marginal yellowing, as well as a yellowing of the veins near otherwise healthy appearing sections. Use virus-and whitefly-free tomato
transplants, as well as pepper plants, which are whitefly
hosts. Transplants should be treated . Commercial growers
can use dinotefuran or bifenthrin for Adults and Oberon for eggs
and nymphs. These products are not readily available to the Home
Gardener , there are several less potent products, and
aphid / whitefly sticky traps
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are also helpful in controlling populations .
which I have found to
be effective. 
" A proven
broad-spectrum liquid fungicide for use on vegetables, fruit
trees, roses, flowers, lawns, shrubs and shade trees.
Controls many diseases including rust, leaf spot, blights,
anthracnose, powdery mildew, fruit rots, etc."
used in the treatment
/ prevention of Bacterial Speck