Can I Eat My Leeks? – Identifying Common Leek Diseases

12th Nov 2024

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Veg – Leek

Have you found spots or patches on your Leeks? Can you still eat your Leeks?

Don’t dig them up and throw them away yet!

Let’s take a look at a few common diseases of Leeks to see whether you can still take your leeks to the dinner table.

Leek Rust

It’s November in the Vegetable Garden and half of my Leeks have yet to be harvested and are still in the ground.

I noticed last week that Leek Rust has appeared on the leaves and I’m hoping I can still eat them.

What is Leek Rust?

Leek Rust is a fungal disease that strikes on members of the allium family like Leek, onion or garlic.

Leek Rust is patches of yellow and orange raised up nodules on the leaves. If the disease is left to spread it will turn the leaf brown so that it dies and falls off.

How to avoid Leek Rust?

Leek rust thrives in wet conditions.

The best way to not get rust on your leeks in the first place is:

Space your Leeks apart for air flow so the air can dry the soil.
Dig up Leeks when they are ready for harvest and not leave them in the ground during wet periods.
Do not grow Leeks, onions or garlic in the same ground next year just in case the fungus is still in the soil.

Can you eat your Leeks if they have a rust on?

Yes, the disease only affects the leaves and not the white bit of the leek we eat.

Just peel off the leaves and any affected areas and cook and eat the rest of your leek.

Harvest your leeks as soon as you see the Leeks Rust as the disease will spread to all of your leek leaves.

Do not compost your Leek Leaves as the disease will spread in your wet compost heap and infect other material.

Allium Leaf Miner

What is Allium Leaf Minor?

This is a tiny fly approximately 3mm in length, they lay eggs on the plants in early Spring (March to June). They eat the inside of the leaf which is where the term ‘Leaf Minor’ originates and the larvae which are brown, bury into the leaves and stem.

The long streak of white dots to the inside of the leaf is very visual and causes other infections in the plant as the plant becomes weaker.

The Allium Leaf Minor Pest will actively seek out plants that belong to the Onion Family.

Signs of Allium Leaf Minor Damage to Plants

Leaf Distortion and twisting as the leaves are attacked by the fly and larvae.
White lines running down the stem into the white edible section with brown pupae buried in it.
Lines of white dots along the foliage.
Rotting in bulbs ready to harvest in August.

Allium Leaf Minor – Solutions

Insect Mesh to cover the plants during the egg laying period of March & April. Also they are active in September to November.
Sow Leek seeds at a different time of the year not in Spring during the egg laying period.
Crop Rotation by moving where the plants grow, you may be able to avoid the pest problem for a different years.