Plant diseases in the Phytophthora genus are the primary cause of loss with established Pindo & Windmill palms but it can usually be prevented.

Disease causing pathogens in the Phytophthora family can attack and kill Pindo (Butia sp.) and Windmill (Trachycarpus sp.) palms in established landscapes and should be guarded against. Losses attributable to Phytophthora organisms form the great majority of post establishment losses with these two families of palms. The pathogens can be air or water borne and are fairly common in Texas and the rest of the southern United States. Early stage infection causes the loss of the lowest set of leafs and a mild discoloration of the remaining leafs. Mid stage infections will have the two lower sets of leafs dead and the spear leaf becoming brown and necrotic. The final stage is the loss of the meristem tissue and the death of the palm. One effective means of guarding against Phytophthora infection is through the periodic application of a chemical disease control agent known as Mefenaxum. Mefenaxum is sold generically but it is commonly available as the active ingredient in a product called “Subdue” or “Subdue Maxx”.

In our experience periodic applications to the canopy and root system of susceptible host species palms substantially mitigates the risk of Phytophthora infection and the periodic drenches will also help to control the development of other less serious but potentially damaging root diseases.Groundworks strongly recommends that owners of these species of palms have them sprayed and soil/root drenched (3) times annually utilizing Mefenaxum as a preventive measure. When performing the canopy spray, it is very important that the spear leaf be thoroughly drenched. In the event a palm is seen to be demonstrating early or early/mid stage Phytophthora infection, spear leaf drenches utilizing Mefenaxum will often times reverse the disease and save the palm however, once the meristem tissue under the spear leaf is dead, the palm is dead so you need to either catch the disease early or prevent its establishment all together. Applicators are cautioned to closely follow the label instructions when applying any chemical; the label is the law.