Frangipani rust, or Coleosporium pluymeriae, is a fungal disease that affects plants in the Plumeria family. It is spread from branch to branch, and even tree to tree by spores carried on the wind that are then implanted on frangipani leaves. While frangipani trees are usually quite resilient, especially in their ideal tropical climate, frangipani rust is a very common problem and can affect their overall health.
If this fungal disease plagues your frangipani tree, it will most likely appear during the hotter months when the rainfall cycle is heavier.
Let’s find out what frangipani rust actually is, how to identify if your plant is affected and what to do to get rid of it.
What is frangipani rust?
Frangipani rust is a fungal disease that affects frangipani trees. This disease forms a powdery, yellow-orange pustule formation on the underside of frangipani leaves.
Frangipani rust, or Plumeria rust originated in Central and South America and has unfortunately spread down the eastern coast of Australia. It currently exists in Queensland and northern NSW, but it is continuing to spread south.
Is frangipani rust bad for your frangipani tree?
Frangipani rust is detrimental to your tree, as the rust growing on the underside of leaves reduces your tree’s ability to photosynthesize and gather all the nutrients it needs to survive.
Although Plumeria rust may not kill your tree entirely, it will cause defoliation or loss of leaves. This is especially pertinent for younger frangipani trees, as they are less mature and established.
How to identify frangipani rust
Frangipani rust can be identified on both the top and bottom of the leaf.
For the bottom of the leaf, if you run your hand on the underside of the leaf, your fingers will turn a reddish brown. You can also simply lift the leaf and inspect it visually. If there are many tiny dots or pustules that are a rusty colour, then frangipani rust is the most likely probability.
For the top of the leaf, if you can see chlorotic spots and lesions running through the leaf, then the leaf’s photosynthesizing capabilities have been compromised. This means that your frangipani tree is unable to get the nutrients it needs from the photosynthesizing process, and it may be diseased with frangipani rust.
How do you know if your frangipani is affected?
You will know if your frangipani tree has rust if the underside is covered in rust-coloured pustules, or if the topside of the leaf has chlorotic lesions on it. If your tree has begun to lose its leaves, then frangipani rust has affected it on a large scale.
Can frangipani rust affect other plants?
Frangipani rust cannot affect other plants. Although it is spread through spores being carried on the wind, it can only affect trees that are part of the Plumeria family. This includes all of the varieties of frangipani trees under this umbrella. Frangipani rust does not affect Australian native frangipani.
Can you prevent your frangipani leaves from rusting?
The good news is, you can use several techniques to prevent your frangipani tree from getting Plumeria rust, including:
- Before purchasing a frangipani tree or taking a cutting, check under the leaves for any rust pustules that may have formed.
- The most effective prevention for frangipani rust is by practising good garden hygiene. This means keeping your plants happy and healthy through regular maintenance, cleaning and feeding.
- If your frangipani is showing signs of rusting, make sure to keep it as dry as possible, and avoid wetting leaves. This will help prevent spreading of the fungal disease.
How to get rid of Plumeria rust
No cure or treatment can fully rid your frangipani tree of rust. There are no sprays or fungal treatments that are currently available in Australia for ridding your tree of frangipani rust.
For fully mature trees, if they do become diseased with Plumeria rust, it is not a huge risk. Instead of focusing your efforts on getting rid of the rust, it may be best to try and stop it from spreading instead. Complete the following steps:
Step 1
Remove infected leaves. Try to avoid dropping any spores or ‘pustules’ onto surrounding leaves during the removal process.
Step 2
Do not compost infected leaves. Instead, place them in your green waste bin or take them to a waste facility. After handling infected leaves, do not touch healthy leaves or frangipani tree.
Step 3
Use a generic rust removal product, such as myclobutanil. While it is not registered for removing frangipani rust, it may help along the process of removal.
