If you judge a community by the talk that comes up at its social gatherings - your child's baseball games, a neighborhood barbecue, the grocery store line or chance Sunday Market or post office meeting, you'd think we were all about slugs and snails.
I addressed the slug issue, and it's a big one this year, in last week's column. The news from Oregon State University that less toxic iron phosphate slug bait proves effective against the common gray slug cheered me since I am loath to use metaldehyde baits in the garden with our pets and children nearby. Granted, measures have been taken to make them less toxic, but I still fret and am willing to sacrifice some plants to slugs and snails who make their way around the little rings of "Worry Free" and "Sluggo" that I have served up in the garden and greenhouse.
That said, and upon further investigation, it's unclear to me that the OSU results apply to the European black slug in its black or red form, as well as the gray garden slug. While we call the European slug black, it's predominantly red in Western Oregon (don't ask me why!). We've had many different slug species in our garden in the past, but 2005 seems to be the year of the "red" European black slug. I still plan to heed the OSU researchers and to dutifully serve up rings of iron phosphate bait. I'll get back to you on this one. Thanks, too, to reader Dave Issacs who recently e-mailed me with this tidbit that has proven effective for him against slugs - a light solution of household ammonia and water administered by spray bottle. Plus, his plants have appreciated the nitrogen tonic provided by the ammonia.
As for snails, well, I've heard an earful in the past few weeks. Reports have ranged from snail onslaughts in sandy coastal gardens to snails in the top of an ornamental plum tree, happily munching their way from the crown down. Most likely these are brown garden snails, introduced years ago as an exotic, and for the purpose of being cooked up in butter and garlic and served as escargot. I admit, I love them in a dish with garlic and butter. Munching away the tops of my lemon cucumber seedlings, I do not.
According to a missive from Robin Rosetta, horticulturist with Oregon State University's Research and Extension Center in Aurora, there have been approximately 12,000 mollusk interceptions at U.S. ports, airports and border crossingsin the last 10 years. These interceptions have involved 490 terrestrial and freshwater taxa. Interestingly, one of the most common routes of entry for exotic snails is on imported tiles (about 2,000 interceptions). Cargo containers on ships are also common means for snails to sail into new locations. The Department of Homeland Security - Customs and Border Patrol - spends considerable time inspecting these containers, inside and out, for freeloading snails. Goodness! Terrorist snails!! There have been 14 exotic snail species found and 121 interceptions during routine inspections at the Port of Portland in the last decade.
The brown garden snail, Cantareus asperses, is reported to cost the state of California $7 million to $10 million annually. It feeds on a wide range of plant material and can commonly be found climbing into trees and shrubs. Much of the concern about alien snail establishment in the Pacific Northwest is concentrated on several families of snails, in particular snails originating from locales with Mediterranean climates, much like our own in Oregon.
"These snails may easily adapt to the mild conditions presented in the Pacific Northwest," explains Rosetta. "When hot or cold temperatures arrive, they withdraw into their shells. They seal the opening with a thin layer of hardened mucus and calcium, allowing them to 'siesta' until conditions are more favorable, namely warm, moist and humid."
Snails can be contained using the same methods as slugs, such as cleaning up garden debris, handpicking and discarding, and checking new plants carefully before bringing them home from the nursery or a friend's garden. The bait option works, too.
Cathy Peterson belongs to the Clatsop County Master Gardener Association. "In the Garden" runs weekly in Coast Weekend. Please send comments and gardening news to "In the Garden," The Daily Astorian, P.O. Box 210, Astoria, OR 97103 or online to email@example.com