Removal of infected leaves and improving air circulation is helpful. It is also beneficial to avoid overhead irrigation. Although not usually necessary, applications of fungicides can be made when new growth emerges in the spring. Among the compounds registered for use in Connecticut is sulfur. Consult the label for dosage rates and safety precautions.
Vines occasionally collapse for no apparent reason.
This can sometimes be attributed to site and soil temperatures. Although clematis need full sun in order to flower, they prefer a fairly cool root system. This can be obtained by mulching the base of the plant. Insect Problems Clematis borer, Alcathoe caudata. The larva of this clearwing moth is a borer in the fleshy roots of clematis, especially Clematis virginiana and C. jackmanii .