{"id":542,"date":"2017-11-30T23:43:40","date_gmt":"2017-11-30T23:43:40","guid":{"rendered":"http:\/\/blogs.oregonstate.edu\/mgmetro\/?p=542"},"modified":"2017-12-27T07:16:57","modified_gmt":"2017-12-27T07:16:57","slug":"slugs-snails","status":"publish","type":"post","link":"https:\/\/blogs.oregonstate.edu\/mgmetro\/2017\/11\/30\/slugs-snails\/","title":{"rendered":"Slugs & Snails"},"content":{"rendered":"

Natter\u2019s Notes <\/strong><\/h1>\n

Slugs & Snails<\/strong><\/h1>\n

Jean R. Natter, OSU Master Gardener
\n<\/strong><\/h3>\n

Snails and slugs. Ugh. Slime and holey leaves. Yuck. Oregon\u2019s rainforests offer prime habitat where slimy pests thrive.<\/p>\n

Pests & natives<\/strong><\/h3>\n
\n \"\"<\/a>\n
Fig 1 \u2013 Newly hatched slugs, 1 day old. (J.R. Natter; 2010-10)<\/figcaption>\n <\/figure>\n

\u201cOf the 29 species of slug [in Oregon], 15 are exotic.\u201d (Resource #2.) Of those, the gray field slug is the scourge of home gardeners and commercial growers.<\/p>\n

Slug lifetimes vary, from one to two years, according to the kind at hand. (Fig 1) But it\u2019s a different story with snails. Brown Garden Snails (BGS) live to 4 years, Giant African Snails \u2013 they\u2019re not here yet \u2013 7 to 12 years.<\/p>\n

Invasive Brown<\/strong> Garden Snails<\/strong>, Cornu aspersa <\/em>were deliberately imported from Europe to California during the mid-1850s to be an upscale edible served in garlic-butter to moneyed goldminers. (Fig 2) Unfortunately for gardeners, snails escaped. Worse yet, when the market went bust, unsold stock was released. (More info at Pacific Northwest Nursery IPM: http:\/\/oregonstate.edu\/dept\/nurspest\/brown_garden_snail.htm<\/a>.)<\/p>\n

The native Pacific Banded Snail<\/strong>, Monadenia fidelis<\/em>, resembles BGS, but has different habits. It primarily inhabits wooded areas, and is seldom a garden pest. When you compare the brownish shells of BGS and Monadenia<\/em> side-by-side, it\u2019s easy to see that the pattern on BGS is somewhat tweedy whereas Monadenia<\/em> is strongly banded. (Fig 3)<\/p>\n

The Gray Field Slug<\/strong>, Deroceras reticulatum<\/em>, also called the milky slug, has cloudy mucus. Although it\u2019s a rather small slug, just 15 to 50 mm long \u2013 about \u00bd- to 2-inches \u2013 it\u2019s a<\/p>\n

\n \"\"<\/a>\n
Fig 2 \u2013 Brown Garden Snails in the PNW often have very fragile shells., (J.R. Natter; 2012-05)<\/figcaption>\n <\/figure>\n

serious pest in both commercial agriculture (especially grass seed producers) and home gardens.<\/p>\n

The European Red Slug<\/strong>, Arion rufus<\/em>, is an accidental import from Europe. A showy one. When disturbed, it contracts into a bell-shaped blob.<\/p>\n

Leopard Slugs<\/strong>, Limax maximus<\/em>, are impressive because of their 4- to 8-inch length when extended. If you\u2019ve ever found a mess of slime on a wall, window, or screen, likely this slug and an intimate buddy were the source. During their unique mating practices, the pair of slugs entwine around each other while suspended from a sturdy strand of mucus. (Explicit images at \u00a0http:\/\/oregonstate.edu\/dept\/nurspest\/Limaxmaximuscourtship.htm<\/a>.<\/p>\n

Management of slugs and snails<\/strong><\/h3>\n

– Natural slug predators exist, but are unlikely to limit populations as much as desired, especially if you plant from seed \u2013 seedlings are choice nibbles — or if your favorite plantings are leafy greens or hostas.<\/p>\n

– Several different night-working, predaceous ground beetles labor on your behalf. Scaphinotus<\/em> species, for one. (See https:\/\/www.flickr.com\/photos\/oragriculture\/23611267674\/in\/photostream\/<\/a>)<\/p>\n

– Regularly scheduled search-and-destroy missions, either early day or late evening. Besides that, revenge feels good!<\/p>\n

– Forget about sharp things. You know; stuff like DE, coffee grounds and\/or crushed filbert shells. Slime has a purpose, one of which is protection. Plus, such barriers must remain dry. (See \u201cSnail barriers\u201d – http:\/\/calag.ucanr.edu\/archive\/?article=ca.v037n09p15<\/a>.)<\/p>\n

– If you use baits, the best time to apply them is before the snails and\/or slugs mate and lay eggs. Some species do so in August, others during fall. Then, some repeat in March.<\/p>\n

The future of management <\/strong><\/h3>\n
\n \"\"<\/a>\n
Fig 3 \u2013 Differentiate between the native Monadenia fidelis (L) and the pest Brown Garden Snail, Cornu aspersa (R). (J.R. Natter; 2014-04)<\/figcaption>\n <\/figure>\n

As you may know, gardeners in Europe supplement the natural populations of soil-dwelling, slug-killing nematodes (Phasmarhabditis hermaphrodita<\/em>) with commercially reared preparations of the same tiny beasts. (See http:\/\/www.slugoff.co.uk\/killing-slugs\/nematodes<\/a>.)\u00a0 But, due to strict regulations, those nematodes can\u2019t be exported elsewhere.<\/p>\n

But wait. Help may be on the way. Rory McDonnell was hired by OSU about 2 years ago as the Invertebrate Crop Pest Specialist to help farmers manage pesky slugs and snails. (Yea! Gardeners will benefit, too.) He has since located a domestic strain of Phasmarhabditis hermaphrodita<\/em> on the OSU campus. Just as with all potential biological control agents, requirements include extended testing and evaluation prior to formulation and release of a commercially available product. \u00a0(Keep your fingers crossed.)<\/p>\n

McDonnell is also working with essential oils and novel attractants. Among the latter, an extract from cucumber slices looks particularly promising.<\/p>\n

<\/h3>\n

Illegal in Oregon<\/strong><\/h3>\n

Oh, yes. Forget about pitting decollate snails, Rumina decollata<\/em>, against pest snails and slugs. These predators are legal only in the 7 southern most counties of California. Simply put: Decollates are illegal in Oregon.<\/p>\n

Resources<\/strong><\/p>\n

    \n
  1. \u201cSnails and Slugs\u201d- Practical advice for day-to-day management: http:\/\/ipm.ucanr.edu\/PMG\/PESTNOTES\/pn7427.html<\/a><\/li>\n
  2. \u201cSlugs and Snails in Oregon\u201d (J. Vlach, Oregon Dept. of Agriculture): Helps identify Oregon\u2019s commonly encountered slugs and snails; prints well if set up with 2 pages per sheet. http:\/\/www.oregon.gov\/ODA\/shared\/Documents\/Publications\/IPPM\/ODAGuideMolluscs2016ForWeb.pdf<\/a><\/li>\n
  3. \u201cSlug Portal\u201d – All-in-one resource about slugs in Oregon. Lots for slime devotees to learn there, including identification, the life of a slug; monitoring; management; research; and more. Go to https:\/\/agsci.oregonstate.edu\/slug-portal\/identification<\/a>.<\/li>\n
  4. \u201cTerrestrial Mollusc Tool\u201d – In-depth identification tool for enthusiasts.: http:\/\/idtools.org\/id\/mollusc\/index.php<\/a><\/li>\n<\/ol>\n

    (Click the link below for PDF containing the above text and all the images.)<\/strong><\/p>\n

    Snails and Slugs PDF<\/a><\/h3>\n","protected":false},"excerpt":{"rendered":"

    Natter\u2019s Notes Slugs & Snails Jean R. Natter, OSU Master Gardener Snails and slugs. Ugh. Slime and holey leaves. Yuck. Oregon\u2019s rainforests offer prime habitat where slimy pests thrive. Pests & natives \u201cOf the 29 species of slug [in Oregon], 15 are exotic.\u201d (Resource #2.) Of those, the gray field slug is the scourge of… Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":8248,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[1179565],"tags":[],"class_list":["post-542","post","type-post","status-publish","format-standard","hentry","category-natters-notes"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/blogs.oregonstate.edu\/mgmetro\/wp-json\/wp\/v2\/posts\/542","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.oregonstate.edu\/mgmetro\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.oregonstate.edu\/mgmetro\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.oregonstate.edu\/mgmetro\/wp-json\/wp\/v2\/users\/8248"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.oregonstate.edu\/mgmetro\/wp-json\/wp\/v2\/comments?post=542"}],"version-history":[{"count":14,"href":"https:\/\/blogs.oregonstate.edu\/mgmetro\/wp-json\/wp\/v2\/posts\/542\/revisions"}],"predecessor-version":[{"id":651,"href":"https:\/\/blogs.oregonstate.edu\/mgmetro\/wp-json\/wp\/v2\/posts\/542\/revisions\/651"}],"wp:attachment":[{"href":"https:\/\/blogs.oregonstate.edu\/mgmetro\/wp-json\/wp\/v2\/media?parent=542"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.oregonstate.edu\/mgmetro\/wp-json\/wp\/v2\/categories?post=542"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.oregonstate.edu\/mgmetro\/wp-json\/wp\/v2\/tags?post=542"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}