Local vegetable gardeners have been hit with several tomato diseases that are killing their plants. These are Septoria leaf spot, early blight and late blight.

The symptoms of Septoria leaf spot and early blight are dark spots on the lower leaves. The spotted leaves die prematurely resulting in early defoliation, fruit sunscald and poor fruit color.

Late blight is the most devastating of the three diseases. It is a fungus that attacks both tomatoes and potatoes. It can rapidly spread over a very large area and kill the plant in two weeks. The airborne spores can travel up to 50 miles.

The disease affects foliage and fruit. Large greasy, grayish areas develop on otherwise healthy appearing leaves. These areas expand rapidly in wet weather and leaves dry, shrivel and turn brown. Water-soaked spots occur on the stems. Gray green water soaked spots appear on the fruit. Infected fruit, when eaten, poses no threat to people.

Penn State recommendations are dependent on whether you choose to save your infected plant or destroy it.

If you choose to aggressively work to control the disease, here are some steps to follow: As soon as plant surfaces are dry and the sun is shining, remove all leaves and fruit with any symptoms of the disease. Mid-morning is a better time than evening to do this since any spores that are dislodged in the morning are likely to die before dew forms and new infection would become possible.

Try to minimize movement of affected plants during the following procedures: pick affected leaves and fruit and immediately put them in a plastic bag. When finished tie the bag shut and put it in sunlight so that the contents will be killed. Then the bag and contents can be disposed of with other garbage.

Immediately initiate and continue a weekly spray program with a fungicide. Products that contain chlorothanil (Daconil 2787) Mancozeb or fixed copper are suitable.

If you choose to destroy your infected plants, Penn State makes the following suggestions: Mature green fruit can be picked and stored in a dry area where they can be ripened for later use. Do not pull affected plants because this process can dislodge spores into the air where they can be wind-borne to neighboring tomato plants.

The best way to destroy individual plants is to pull a large plastic bag over the plant first. Then the plant can be cut off at ground level, tied inside the bag and continue as above, putting the bag in sunlight and then discarding with garbage.

In the absence of plastic bags, cut the plant stem at ground level, preferably when the plant surfaces are dry and leave to dry in the sun. Old spores will die in about five hours when the humidity is low and no new spores will form on dead plants.

A row of tomatoes can be destroyed by cutting the stalks at ground level and covering the tops of the plant with black plastic typically used for mulching the garden. The heat from the sun is absorbed by the plastic, which will kill the plants and the fungus spores.