Young Palm Trees

• It is best to conduct a laboratory test to determine the causal pathogen before using a fungicide. For infection from Phytophthora, use mefonoxam and fosetyl-Al. The fungicide propamocarb is recommended for use in palm container nurseries only. If the infection is the result of Thielaviopsis, use thiophanate-methyl containing products. In the absence of a lab test, use thiophanate-methyl and etridiazole on younger trees.
  
  

Treatment Suggestions

• All fungicides are used as bud drenches, where the bud, or the point where the new leaves grow, is thoroughly soaked with the chemical. Since the bud is easily accessible in younger trees, timely treatment is highly beneficial in stopping the spread of disease. However, unless trees are treated in time, the infection can also rapidly kill younger trees. Monitor younger trees, especially those in nurseries, regularly and closely. This is particularly important after heavy rains and storms.
  
  

Mature Palm Trees

• As with younger trees, conducting a laboratory test helps to determine the specific chemical requirement to treat disease in a mature tree. In case of infection by the Phytophthora fungus, use fungicides with fosetyl-Al as a bud drench or mefenoxam as a bud or soil drench. If the tree is infected with Thielaviopsis, use thiophanate-methyl as a bud or soil drench.
  
  

Treatment Suggestions

• Given the height of mature trees and difficult accessibility to the bud site, the disease is often detected when it is too late. The application of fungicides is also more difficult in mature palms. The recommended strategy is to use the fungicides as a preventive measure around palm trees when you have confirmed the presence of a pathogen. Often the bud is entirely dead at the time of diagnosis. No fungicide can help the tree if this is the case.