allium rust / garlic rust

Symptoms

Small bright orange-yellow oval pustules on leaves + sheaths, pustules erupt releasing powdery spores, severely infected plants senesce 3-4 weeks early.

Plants affected

• garlic

Easily confused with

• onion thrips

  How to tell them apart: Both attack garlic (Allium sativum) foliage and cause whitish leaf marks early on, but Puccinia allii (garlic/leek rust) is a fungus while Thrips tabaci (onion thrips) is a tiny insect. Rust starts as small pale flecks that quickly raise into bright orange-yellow powdery pustules erupting through the leaf surface — rub a finger across them and you get orange spore dust. Thrips damage stays flat: silvery-white stippling, blotches and streaks running along the leaf, dotted with minute black tar-like fecal specks, and you can often spot the slender yellow-brown insects (under 2 mm) wedged in leaf folds and at the base. No raised orange pustules and no rusty dust means thrips, not rust.

Common questions

How do I recognise allium rust / garlic rust on garlic?

Small bright orange-yellow oval pustules on leaves + sheaths, pustules erupt releasing powdery spores, severely infected plants senesce 3-4 weeks early.

Do I have to report allium rust / garlic rust?

No. allium rust / garlic rust is not a notifiable organism, so there is nothing to report to an authority. Treat it as a normal garden problem.

How is allium rust / garlic rust treated?

Mainly with biological and cultural measures — removing affected material, changing the conditions that favour it, and treating with agents approved in your country. The exact steps and their timing depend on the plant, the season and where you live: Dr. Phyto works them out in a free diagnosis.