Phytophthora citrophthora


What is Citrus Collar Rot

This is a fungal root disease which usually affects the trunk of citrus just above soil level. 



A section of bark around the base of the tree dies back and falls away from the main trunk. Sometimes oozing gum and cracking around the dead section occurs. Leaves turn yellow. Tree loss can occur if left unchecked.


How to protect your plants

Cut the bark back to healthy growth and spray affected bark lesions with Yates Liquid Copper Fungicide Concentrate. Do not allow soil or mulch to pile up above the grafting union. For cultural control, improve air flow by removing any mulch touching the bark of the tree. Improve drainage around the tree if water logging occurs frequently or if the ground is often damp. 


Plants impacted

  • Citrus

Recommended products

More articles


Here's how to recognise and control borers in the garden.

Brown Rot

Brown rot is a fungal disease of citrus fruits. The fungus overwinters in mummified fruit which has either fallen to the ground or is still attached to the tree.

Citrus Rust Mite

If the surface of your citrus fruit looks like its covered in brown rust coloured spots or markings, it's the work of the citrus rust mite. Here's how to identify and control them in your garden.

Citrus Leaf Miner

If the leaves of your citrus distorted with silver patterns or markings, it sounds like you have citrus leaf miner. Here's how to identify citrus leaf miner and how to treat them in your garden.