Over the last few months, I’ve been plagued by perfectly healthy heads of lettuce suddenly wilting and dying. Could it be the cause of fungal diseases, cutworms… bad mojo?? After a great deal of wild guessing, counterbalanced by some careful observations, I’m very excited to announce I’ve figured it out. Wireworms!
Understanding the beast below
A wireworm is unlike any other worm, grub or caterpillar you may find in your garden. It has a hard yellowish body, menacing mandibles, and a rear end that looks like it could double as a bottle opener. When disturbed, it reacts with powerful and rapid movements in a desperate effort to re-burrow back out of sight.
Wireworms are the larvae of click beetles, aptly named for a clicking sound they make when they find themselves on their backs and try to get back on their feet. Unlike most insects with short life cycles, the wireworm takes 3-5 years to fully develop from larvae to beetle. That’s a long time for it to be feasting in your garden!
Wireworms live 6-8” below the soil where they feast on plant roots and tubers. One worm is all you need to lose a whole plant. My wireworms prefer lettuce, but they'll eat just about anything. They're a common agricultural pest of beets, carrots, potatoes, peas, and strawberries. Surprisingly, the adult beetle doesn’t cause damage to plants.
How to manage the wireworms
OVERPLANTING: While I do experience a pang of heartbreak each time I see one of my beautiful lettuce heads collapse, I’m not desperate to control the wireworms. Luckily I plant an insane amount of lettuce and can easily write off the 10-20% the wireworms are eating.
TRAPPING: I love a good experiment so I couldn’t resist making a simple trap suggested by Oregon State University. If you are interested in trapping, see the University’s excellent publication on wireworms and check back for an update how my efforts go. I’ve also read anecdotal accounts that you can use carrots or potatoes to trap wireworms.
DIGGING UP: When I do see a head of lettuce collapse, I immediately dig up the surrounding soil and place it in a tray. I then sift through the soil looking for the wireworm. If I’m lucky, the wireworm hasn’t moved on to a new plant, and I can find it in the soil I’ve unearthed. My chickens love the wireworms, so once I find one, I hand feed it to one of my lucky ladies.
COMPLAINING: I’m don’t have a full proof solution to controlling these buggers, but I’ve noticed a good venting session (like this blog posting) can really help me manage my frustration levels... and you know, that's half the battle.
It's probably a bit of an odd way to relate to the garden, but I find it's thrilling to discover who's killing my plants. I'd love to know if you‘ve had any wireworm issues, and if you have additional suggestions for managing them.