Slugs, Slugs, and MORE Slugs
As you know mild winters and wet spring weather are the perfect conditions for an abundance of slugs. Here, in the PNW, we have garden slugs, both black and red, spotted leopard slugs, and our native banana slugs that are either white, all yellow, or with big black spots. In spring they forage voraciously on the tender schmorgasbord in our gardens. The best way to combat the damage is to reduce their habitat, put up barriers, and set traps.
Slugs prefer moist, cool ground cover to hide in and leaves to eat. Locate your vegetable garden away from evergreen ground covers or place a barrier between ground covers and the garden. Mulch, bricks and rocks are also favorite hiding places for slugs.
After limiting the slugs’ general habitat, a gardener can begin to hunt for the hangers-on. Handpicking is the most direct way to reduce the population. Hunt for slugs at night or very early in the morning; a flashlight is helpful. Methodically follow any slime trails and look into the foliage of all plants, especially the tight leaf axis of hostas and daylilies. Slugs can and do burrow into the top 2 inches of soil, so scratch the soil to look for them.
Eggs and juvenile slugs can also be hunted and disturbed. Frequent cultivation of the soil in spring exposes juveniles for removal and damages eggs. Slug and snail eggs look like translucent tapioca pearls or fish roe approximately 2-4 mm in diameter. They are laid in clusters under mulch, rocks, cardboard, and burlap. They should not be confused with worm eggs, which are small, oval, opaque yellow, and laid singly. Cultivation also disturbs the slugs’ navigational habits, as they follow their own slime trails to frequent feeding places.
One popular and effective trap is baited with beer. To make a simple beer trap, cut a few 1-inch holes near the top of a pint-sized plastic container. Fill the bottom with 2 inches of beer and place the trap in the soil, keeping at least ¼ inch of plastic exposed below the holes. This provides a space for slugs to crawl through, while leaving a protective ledge that keeps ground beetles and other beneficial insects from accidentally falling into the trap. Do not change the beer daily because slugs are attracted to dead slugs. When the beer turns sour and no longer smells of yeast, compost the contents, refill and replace the trap. Slugs can also be trapped under burlap, old boards or overturned pots. Any dark and protected spot lures slugs.
Slugs do not like to migrate over dry soil. PNW weather provides a favorable slug habitat but so does summer irrigation. Surrounding the veggie garden with non-irrigated borders discourages unwanted migrants in summer. Drip irrigation also limits the amount of water on the surface of the soil, making the general summer environment less pleasant to slugs.
The slug barrier that has proven to be best is a copper strip, which works like a shock collar. Similar to the shock that occurs when people rub their feet along carpet, the slug gets a slight electric shock when moving over copper. The strip of copper needs to be at least 3 inches wide and set up vertically like a fence. Form a ring around an individual plant or attach the copper strip to a raised bed or edging material.
Copper barriers should have no gaps where sneaky slugs can slip through. Any slugs that are inside the barrier when erected will be trapped inside. Go out at night and remove any trapped slugs before planting in the ring. Also, remove or trim away any foliage crossing the copper that slugs can use as a bridge to dinner. Be vigilant. Slugs can be very persistent; after all, they don’t have much to do all night except eat.
(Courtesy of Seattle Tilth)
Posted on 06/16/2015 at 01:38:00 PM