ASK THE HORT AGENT
Question What is causing my tomatoes to flop, drop and die?
Answer Leaves and limbs flop or wilt when there is a disruption in the water supply line. This is true whether you are talking about tomatoes or ornamental flowers. Plants wick water into their roots and out through their leaves. As long as the H20 supply line is intact, leaves and stems are turgid and firm. If the water supply runs dry or is blocked, then leaves become dehydrated and floppy.
Nematodes, dry weather, excessive fertilizer and voles can cause plants to wilt. These situations can reduce yield, size, vigor, etc... If the plants do not die, then steps should be taken to identify the cause of the problem.
There are several diseases in the soil which cause a wilting effect. They enter through a plant's roots. The disease begins to grow rapidly in the vascular tissue (blood veins of a plant). The wilt disease will eventually block up the plant's water lines. Basically, the disease is causing the plant to have a fatal heart attack.
There are a few steps you can take to minimize the impact of soil born diseases. First, rotate the crops in your garden. Never plant the same thing in the same area of your garden year after year. Don't even use plants in the same family. Some plants may not show drastic wilt symptoms, yet they serve as hosts for the disease. For example, eggplants, peppers, tomatoes and Irish potatoes are in the same family. None of these plants should be placed in an area more than once every 3 years. It is even better if you can stretch it out to once every 5 or 6 years. Basically, you are trying to starve the diseases out.
Plant resistant varieties whenever possible. This practice enhances, but does not replace rotation. Resistant plants are not disease proof. If it is raining hard, you will still get wet with a water resistant jacket. If the disease pressure is great, then your plants are still at risk. Resistant varieties will be clearly marked on their label.
There are no pesticides to kill wilt diseases. However, they can be managed very well by using rotation, resistant varieties and good cultural practices. Did I mention that there are NO PESTICIDES available to homeowners that will kill these diseases?
One wilt disease cannot be managed by the previously mentioned methods. It is called Walnut wilt. This happens when gardens are located within 50 feet of a walnut tree. These trees produce a chemical called juglone which causes the tomatoes and other plants to wilt. This chemical can stay in the soil for 3 years after the walnut tree is gone. The solution is simple. Don't plant by the walnut tree.
Homeowners that have a very small plot of land, may want to consider container gardening. For more info about tomato diseases, visit http://hgic.clemson.edu/factsheets/hgic2217.htm If you do not have internet access, then call me at 910-893-7533 or email me at firstname.lastname@example.org
Researchers tried incorporating Viagra into tomato genes to stop the wilt. The new plants were still susceptible to the wilt diseases, but they didnít have to stake the plants.
Gary L. Pierce
Horticulture Extension AgentHarnett County