How to Save Dutch Elm Diseased Trees By Pruning

Dutch elm disease (DED), caused by the fungus, Ceratocystis ulmi, is the most devastating shade tree disease in the United States. Healthy elms can become diseased by 1) elm bark beetles that carry the fungus from elm to elm, or 2) through root grafting with already infected trees. Along with wilt symptoms, streaking (sapwood discoloration), a characteristic internal symptom of the disease, progresses rapidly down from limbs inoculated by bark beetles (Allison 1978).

The link address is: http://www.na.fs.fed.us/spfo/pubs/howtos/ht_save/ht_save.htm