Garden Edition: July , Page 2
Plant with slugs in mind
Like deer, slugs have their preferences, some of which are likely to vary by region and species. Notwithstanding, planting any of the following is likely to be a slug invitation so be vigilant: seedlings, hostas, lettuce, delphiniums, cannas, periwinkle, and marigolds.
Some plants either repel or simply don't interest slugs. They might be aromatic, fuzzy, thick-leaved, or prickly. In that category I'd put the thick or blue-leaf hostas (see below), lamb's ear, artemisias, pulmunaria, hibiscus, candytuft, euphorbia, beebalm, shasta, echinacea, sunflowers, rudbeckia. lamium, oenthera, bleeding heart, and foxglove. I imagine, however, that even a normally slug-resistant plant might be nibbled if environmental conditions and slug population determine availability and appeal. Slug-resistant hostas are actually being breed and characteristics of heavy, tough foliage or blue leaves are enough to make a slug look elsewhere.
For a complete list of varieties, see Budd Gardens website below.
Reduce safe harbors.
Keep all decaying plants, leaves, old weeds, and other such things out of your garden. If possible, add space between plants. Don't mulch with grass clippings or anything thicker than three inches or so. Keep mulch a couple inches away from the base of your plants.
This disturbs the eggs by bringing them to the surface, where they dry out and die. Start doing this in the spring and continue hoeing as often as possible. It also exposes weed seeds, but it's a tradeoff.
Patrolling and handpicking.
If you have the stomach for it, this method, done with flashlight or early in the morning, can make a big dent in a garden's slug population. Some gardeners gather slugs with gloves, chop sticks, tweezers or whatever's handy. A jar serves as a handy collection vessel and hot soapy water or a little ammonia will kill them. Using a sprayer to hit them with diluted ammonia or salt has to be done carefully so as not to damage plants.
These are simply artificial shelters for slugs that can be easily inspected. You can buy them (Slug Saloon, The Pit) with various baits or construct a homemade trap with such things as wood, wet carpet, orange or grapefruit halves, moist newspaper, comfrey leaves or an upended pot. Sometimes the trap itself can be the bait, like a moist newspaper (a refuge) or an orange half (food), but some gardeners add bait like a bit of cat or dog food, lettuce, calendula, beans, horseradish leaves, comfrey leaves, marigolds, plaintain and zinnias.
The most well known bait by far is beer. A shallow cat-food can containing beer is placed in the garden. The beer lures the slugs in and they drown. Previous thought was that any old leftover beer would do but apparently that's not correct. According to Colorado State University entomologist Whitney Cranshaw's test, the brand makes a difference. Besides different kinds of beer, Cranshaw's test used non-alcoholic ones, Chablis wine, tap water, and a sugar, water-yeast mix. His research showed that 'near beer' Kingsbury Malt Beverage (a Heileman product) beats all the competition.
The top three beverages were, in order: Kingsbury Malt Beverage, Michelob, and Budweiser. Cranshaw went even further, finding that flat beer (beer that had been exposed to air for 48 hours) also made a difference, depending on the beer. Flat Budweiser, for example, caused sharply reduced slug capture but flat Pabst Blue Ribbon showed no detrimental impact. So you might want to experiment for yourself to see what your slugs like.
When it comes to emptying the trap, what to do? One option is to throw the mess into the compost pile. Throwing it in the garbage or flushing down the toilet seems like a real waste. Consider feeding it to fish and ducks or putting it on a bird feeder.
This very effective but expensive method creates a barrier around a raised garden, a particular plant, or a container. The slime on the slug reacts with the copper, creating an electric charge that stings the slug. If used as an edging, be sure to keep it free of dirt and grass.
Nemaslug contains microscopic nematode worms that reproduce inside the slugs. It is mixed with water and watered onto the garden and should give protection for up to six weeks. However, it needs to be kept in the fridge and requires moist soil for optimum performance. Not recommended for use on heavy clay soil.
The decollate snail Rumina decollata is a specific predator of snails and some types of slugs. Originating from North Africa, the Decollate snails live for from 1 to 1 1/2 years and lay about 200 eggs per year. The predatory snails are particularly fond of slug and snail eggs but do not bother plants. One site says that a normal yard usually needs about 100 snails; an acre, about 1,000.
Coconut oil soap. Concern Slug Stop is a pest barrier designed to stop slugs and snails. The product is made from coconut oil soap and is claimed to work for up to three weeks, even in rainy weather.
Iron phosphate. Many organic gardeners, including myself, use Escar-Go or Sluggo, products that contain this naturally occurring organic compound. It's non-toxic and breaks down into fertilizer. It can be used around wildlife, pets, and children without fear of toxicity. According to the product label, once it's eaten by the snail or slug, the mollusk stops feeding and dies within 3-6 days. Both products are supposed to remain effective even after a rain. Reapplication is necessary as the bait is consumed.
This should be a last resort, considering the potential harm to wildlife and pets. Typically most snail and slug control products contain metaldehyde or methiocarb, both toxic materials to mammals.
Slugs contacting or ingesting the products react by producing copious amounts of slime and eventually die of dehydration. Molluscicides are most effective on warm, humid nights and success depends on the slugs actively foraging for the bait and consuming a lethal dose. The best way to handle such pesticides is to place them in a closed container with holes punched in it to allow slugs in but to keep wildlife and pets out. Put the containers out in the evening and do not water before or after application. These products are rapidly inactivated by sunlight so position the containers underneath leaves late in the day.
Of the two, methiocarb is less affected by high humidity conditions or cool temperatures. However, it's also is more toxic to mammals and its use is prohibited near food crops It's important to read all the manufacturers' instructions before using any pesticide. Finally, it should be mentioned that even slugs and snails have their good sides. As we all know, everything has its purpose. As herbivores, they remove dead plant tissues, thereby playing an important role in nature's cleaning processes.
Sources for the non-toxic products:
Budd Gardens: buddgardens.co)
Gardens Alive: gardensalive.com
Biological Control Network: biconet.com
Buglogical Control Systems: buglogical.com
Biological Control Network, biconet.com
Planet Natural: planetnatural.com
Applied Bio Pest: biopest.com