Seiridium canker is becoming a serious problem of Leyland cypress. This disease may kill young shoots, older branches and in some cases entire trees. Bleeding cankers are sometimes observed on the trunks of infected trees. This fungus may be spread by wind and rain and possibly insects, birds, or infected nursery stock. Trees that are stressed by transplant shock, drought and/or high or low temperature may be more likely to be infected by this disease. Leyland cypress should be planted in well drained, fertile soils and irrigated during periods of drought. Diseased shoots and branches should be removed. Heavily infected trees should be destroyed. Chemical control does not appear to be an option as fungicides are not considered an effective or practical means for controlling canker diseases in general or Seiridium canker in particular and healthy trees would have to be sprayed indefinitely to prevent infection.