Rust

Plants affected by rust will have raised pustules on the underside of leaves which break to release rust-colored spores. The upper surface of affected leaves will often have yellow spots. Eventually, affected leaves may fall off.

It is highly recommended to try physical prevention/control methods before resorting to chemical control. If you choose to use a fungicide, select a product that is labelled for rust and rotate products where possible to minimize resistance. Not all fungicide products work on all types of fungal diseases. Check local regulations (or your local Extension Office where applicable) to identify products that can be used in home gardens in your area. Follow label instructions carefully for safe and effective fungicide application and to ensure that edible crops are safe to harvest. Test fungicide on a few plants before widespread application. Spray fungicides in the late evening and try to avoid spraying during blooming to minimize negative impacts on pollinators- some fungicides are directly lethal to pollinators, and others can have indirect negative impacts. Fungicides may not help if the plant is already severely diseased; it works best when used early (or preventatively in cases where you know you have a particular disease susceptibility). Severely diseased plants may need to be removed and disposed off site.