Bug Watch: Frangipani rust
Photo - Linda Ross
This is a fairly new disease (Coleosporium domingense syn C. plumeriae) in Australia. It is believed to have arrived from Florida in an infected frangipani cutting 15 years ago. You’ll see small golden orange pustules on the reverse of the leaf, which quickly cover the tree. The rust spores are windblown so spread to other trees nearby. Frangipani rust can cause defoliation, reduced flowering and reduced vigour due to reduced photosynthesis. The rust doesn’t affect all frangis equally: the pinks and reds seem to be resistant, while the common white and yellow or ‘Celadine’ are the worst affected.
Spray from November through to February/March with either Yates Rose Shield or Eco-Rose. Bin any affected leaves to stop the spread of the disease.