thermotherapy, a technique to eliminate virus diseases from grapevines by growing infected plants at high temperatures (about 38 °C or 100 °F), and then propagating from shoot tips. These shoot tips can produce plants free of virus diseases, but diseases such as fanleaf degeneration virus are eliminated much more easily than others—leafroll, for example. Each tip produced must be checked to see whether it is virus-free, and can become registered as a new clone. New techniques of tissue culture have generally been found more effective at virus elimination. Thermotherapy should not be confused with hot-water treatment.