Evaluating IPM Strategies and Alternative Fungicides for Reduction of Rhabdocline Needle-cast on Douglas Fir

Douglas-Fir is a major component of the Christmas Tree and Nursery industries in NY state. Over 40 growers and nurseries are producing Douglas-fir in Monroe and Wayne Counties alone. In addition, most retail nurseries and garden centers sell large volumes of this evergreen species and furthermore, the landscape industry of both counties relies heavily on Douglas –fir in commercial and residential settings. During random visits to several wholesalers and growers alike, trees infected with Rhabdocline needle-cast have been notably poor in quality. Often the infections are so severe that affected trees have cast such a large percentage of 2 nd year needles as to become unacceptable, as either Christmas trees or landscape specimens, and thus are lost. One grower estimates losses approximately $10,000 per year due to this needle-cast disease. Reports in Cornell’s ornamental pest newsletter, Branching Out , Indicate the problem is statewide