What’s eating the leaves of my parsley, basil, beets?

(Question)

Something is eating my beet tops as well as parsley and basil leaves (leaving holes in the leaves).  Is this earwigs? Something else?  How should I control them?

 

 

 

 

 

 

 

 

 

(Answer)

As this has been a very wet spring/summer, the hungry critters that are attacking your tender leaves are likely slugs or – as you suggest, earwigs.

Both these pests munch at night, and you can catch them in the act by heading into the garden in the evening, flashlight in hand – and peeking at the leaves of your plants.

Slugs leave ragged holes in leaves close to the ground and often leave a slimy trails that once dry, look shiny. Earwigs chew holes in leaves – they tend to make holes all over younger leaves, while chewing around the edges of older leaves — often these leaves look ragged.

If it’s slugs:  Here are a few suggestions about how to control them (see the references below for more options and details) —

WATER: Water plants in the morning, so they will be dry by the evening. As slugs love dark, damp environments, try to keep your garden light and dry.

TIDY: Keep the garden tidy – e.g., get rid of weeds and debris around the plants, and don’t crowd plants – maximize air circulation to keep the soil surface relatively dry.  This this eliminates daytime hiding spots for slugs. Consider your choice of mulch – large bark and wood chips are great places for slugs to hide. They seem to find shredded pine bark is less attractive, and are repelled by cocoa hulls.

BARRIERS: Slugs hate crawling over dry, dusty or scratchy, such as diatomaceous earth, cinders, coarse sawdust, gravel or sand. It makes them secrete lots of mucous to get past these materials, and they get tuckered out and die. Surrounding your plants with a border of any of these inert materials should help control slugs. Copper strips can also be used, but may cause safety problems for children or animals. –

HAND-PICK: You can hand-pick slugs off plants at night using your trusty flashlight and a pair of disposable gloves. This is pretty time-intensive as not all slugs are active each night – you would need to be patient to see an impact on the slug population.

TRAP: If your plants are in pots, you can keep slugs from them potted plants by supporting the pots over a pan of water. Slugs also will go to shallow dishes containing beer or baker’s yeast dissolved in water – they’ll drown. You can also trap slugs by using boards that are raised about an inch off the ground, or inverted melon or grapefruit rinds — the slugs will gather and you can scrape them off every morning.

PREDATORS: Toads are a natural enemy of slugs, and some people claim that ducks keeps a garden slug free.  Perhaps you can attract these animals to your garden…

For earwig control, keep the garden clean and dry (as for slugs, above). Trap them by filling shallow tin cans (an old tuna can is fine) with ½ inch of vegetable oil, placed in the garden. Alternatively,  use a rolled up newspaper or paper towel tube filled with straws; seal this at one end and put in an area of the garden where you have seen earwigs. Once they crawl inside, they will not be able to escape.

Note: Earwig damage is usually not severe, and these critters prey on garden insects, including pests – so it’s recommended that they be tolerated.

Here are some helpful resources that provide lots of details about how to identify the pests and deal with them:

University of Rhode Island Landscape Horticulture Program – Slugs (factsheet)

Nova Scotia government – Earwig prevention & Control fact sheet