Garlic

Onion white rot

What you will see

Yellowing and wilting leaves, rotting roots and onion base.

The source says: it is a serious disease of the onion family.

How to protect

1. Prevention

   • You can practically never clean soil once it has white rot: prevent it being introduced (soil on tools and footwear).
   • Do not grow alliums on affected soil.
2. By hand as soon as it appearsDig up affected plants together with the surrounding soil and dispose of them; no chemical soil treatment is available to gardeners.

Garlic fly

What you will see

Larvae eat the innermost young leaves of winter garlic. In spring the new leaves are notched, twisted or stop growing; the plant looks grass-like and the cloves stay small. It attacks only winter garlic, not spring garlic.

The source says: it can cause severe damage to garlic.

How to protect

1. Prevention

   • Cover garlic with crop netting or fleece on the very first warm spring days and leave it covered until mid to late April.
   • Choose hardneck varieties (those that send up a flower stalk); they are less attacked and the damage shows less.
   • Spring garlic is not attacked by the fly.
2. By hand March to AprilCrop netting or fleece from the first warm spring days until mid/late April.
3. Chemical — only when nothing else helps early AprilA product authorised in your country against biting insects or root flies. The best timing is early April, when 10% of plants have eggs; it does not work at low temperatures.

Leek rust

What you will see

Bright orange pustules on the leaves.

The source says: it is a common disease of leeks and garlic.

How to protect

1. Prevention

   • The disease is worse on soil rich in nitrogen and poor in potassium: feed carefully.
   • Try varieties that suppliers list as more resistant (this is only partial resistance).
2. By hand as soon as it appearsRemove affected leaves and dispose of them; do not overfeed with nitrogen.

Leek moth

What you will see

White blotches on leaves, young plants rot and die; tiny caterpillars are inside the tissue.

How to protect

1. Prevention

   • Cover plants with fine mesh for the whole growing period and rotate crops.
   • Look for white netted cocoons on the leaves and squash them.
2. By hand April to OctoberCollect cocoons and caterpillars and destroy them by hand.

Onion downy mildew

What you will see

Leaves yellow and die back, with a mould layer that is first white, then purple.

How to protect

1. Prevention

   • Avoid crowded and sheltered, windless spots; weed so air can circulate.
   • Do not plant soft, mouldy bulbs.
   • Dispose of affected plants and do not plant onions or shallots there for 5 years.
2. By hand as soon as it appearsRemove affected plants and dispose of them.