Rusty thistles

Thistle Rust (Puccinia punctiformis)

When it comes to our ongoing battle with thistles — and our attempts to control them — we may have a new ally. While wandering around the garden recently, I noticed a Creeping Thistle plant that was looking a bit peaked — pale compared to its neighbours, but showing some dark rusty-red patches as well. A closer look showed it to be heavily infected with Thistle Rust (Puccinia punctiformis), a fungus that is specific to Creeping Thistle. So far, it's only the single plant that has been impacted; the nearby thistle plants all appear to be healthy. However, that may not remain the case. Thistle Rust is now found around the world and is widely used in some places as a biological control agent. Its spores spread on the wind, and either infect new shoots or enter a plant through its roots. Some species of weevil may also spread the spores while feeding. The rust affects the plant's ability to both photosynthise and reproduce, and can eventually kill it. Our bare toes aren't sorry to hear that!

This whole plant is affected