Wax Myrtle Rust Powder: Likely Slime Mold, Check Watering

South Texas wax myrtles have rust-colored powdery growth on trunks; bark cracked underneath. Some dead, then whole shrub dies.

Assessment

• Rust powder likely slime mold—non-pathogenic, just reproducing.
• Real issue: water stress (too much or too little).
• Wax myrtles nearly indestructible except windthrow.

Action

• Adjust watering—sandy soil needs more frequent water for young plants.
• Don't treat slime mold.

Focus on irrigation.