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Rust

Disease Uromyces, Puccinia, and others

Spots or blotches on leavesPowder, fuzz, or mold

A garlic leaf speckled with orange rust
Photo: Downtowngal, Wikimedia Commons (Public domain)
Orange rust bumps on an onion-family leaf, close up
Photo: Peter de Lange, Wikimedia Commons (CC0)

How to spot it

Small raised orange, red-brown, or yellow bumps, mostly under the leaves, that rub off like rust-colored powder.

What it does

Leaves yellow and drop, and harvests shrink.

What to do now

  • Remove infected leaves.
  • Sulfur sprays can slow it if started early.

Keep it away next time

  • Grow resistant varieties.
  • Space plants and water the soil, not the leaves.
  • Clear away infected plants in fall and grow the crop in a new spot.

Helpful supplies

Bypass pruners on Amazon (opens a new tab)

Affiliate links: we may earn a small commission, at no extra cost to you.

Plants it affects

Green beans (bush)Pole beansDry beansGarlicOnion (sets)LeeksAsparagusSweet cornSnapdragonMintRaspberry (summer)Blackberry
Cedar-apple rust

Not sure? Your county extension office can identify it from a photo or sample, often for free.