Allium Rust on garlic has become quite an issue in the past 10 years. Not just in Canterbury, where I live, but in many places of New Zealand. 

It’s a fungal disease that never was that problematic in “the old days”. I used to grow heaps of garlic in Auckland and Christchurch, but slowly, stuff started to become troublesome. 

People complain that this fungal disease strikes in late winter/early spring, and the only thing that stops it from hammering the garlic plants is by regular spraying with copper or copper/sulphur fungicides (organics!). 

“Regular” might be as frequent as every fortnight! The easiest way to identify the rust attack is the yellow pustules that cover the leaf surfaces. 

Rust is transmitted by air movement – the spores float with the wind and can travel from great distances. If you are in a densely populated area with many gardeners that grow onions, shallots, leeks, and other Allium species, the spores will be everywhere. 

Another thing that seems to cause Allium Rust is by having too much moisture in the soil – keep it as dry as you can. 

Traditionally, garlic used to be planted on the shortest day (third week of June) and harvested around the longest day (just before Christmas), but I’ve done some trials for the last half a dozen years or so to bring those dates forward by at least a month and a half. 

With rather little success, to be frank – I still need to spray regularly and when I am on the road and miss one of the sprays, the leaves will turn that yucky yellow-orange with the rust. 

I tried growing inside my old tunnel house (drier conditions and no fungal spores having access to the young plants) – now that made a bit of a difference! 

This year I decided to go inside my brand-new tunnel house. A week ago (on the 4th of May) I planted a few narrow beds of garlic in various lengths between other plants (including my late-comer tomato plants). 

Keeping the tunnel house openings closed as much as possible will reduce the fungal spores floating into the tunnel house, and this will avoid infections right from the moment I plant the garlic. 

Remember to keep the garlic reasonably dry – it all works to keep your crop healthy. If you do find some yellow spores on the leaves, spray with some copper/sulphur fungicides. 

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