Leeks

(Question)

I live in Scarborough, Ontario, and have a small vegetable garden.  Last year I got a disease in the leeks – they became all mushy and wasted away.  I believe it is due to some bug laying eggs on the plants.  What can I do about it?

(Answer)

How disappointing to see your awaited vegetable be destroyed.  It’s very important to keep a constant eye on leeks and their progress, watching for any early sign of disease, pests or pest damage to prevent spread of the problem.

I hope you cleaned up and discarded all affected leeks in the fall in the and turned up the soil with a spade or fork to try to get rid of any larvae or adult insects that could overwinter in the soil.  If not, be sure to do so this spring, and if possible, grow your leeks in a different part of your small garden.  This will help control any fungal disease that overwinters in the debris.

If leeks are grown in good rich soil and full sun, they don’t usually have many problems.  There are, however, various insects that feed on them.

One possible insect attacking your plants, which are part of the Allium/Onion family, may be the Leek moth and its larvae.  This moth can cause mushy rotting onions, leeks and garlic in Ontario, mainly since the 1990’s.

A second insect problem could be an infestation of thrips, which are tiny, dark insects that commonly affect plants in the onion family.  If you see these early you can spray them off your plants with water.

Another possible insect culprit is the onion maggot, a small white larva found feeding at the base of the plant.

I suggest the first thing you do is try to identify which problem/pest you have, and the website links below will give you further information should you wish to read more.

https://www.omafra.gov.on.ca/english/crops/facts/08-009.htm

https://www.canadiangardening.com/gardens/fruit-and-vegetable-gardening/sleek-leeks/a/20351