{"id":81,"date":"2011-06-01T18:29:09","date_gmt":"2011-06-02T01:29:09","guid":{"rendered":"http:\/\/blogs.oregonstate.edu\/treetopics\/?p=81"},"modified":"2012-10-25T14:57:00","modified_gmt":"2012-10-25T21:57:00","slug":"green-alder-sawfly-a-new-invasive","status":"publish","type":"post","link":"https:\/\/dev.blogs.oregonstate.edu\/treetopics\/2011\/06\/01\/green-alder-sawfly-a-new-invasive\/","title":{"rendered":"Green Alder Sawfly – A New Invasive"},"content":{"rendered":"

By Paul Oester and Dave Shaw, OSU Extension Service<\/strong><\/p>\n

History
\n<\/strong>A native of Europe, North Africa and the Near East, the green alder sawfly (Monsoma pulveratum<\/em>) (Hymenoptera: Tenthredinidae) was first found in North America in eastern Canada in the early 1990\u2019s, then in Alaska in 2004.\u00a0 More recently, the green alder sawfly was identified in trap samples in nine Washington counties and one Oregon county (Multnomah).\u00a0 Examination of insect collections at Western Washington University indicates that this insect has probably been present since 1995.\u00a0 It was first detected in the contiguous United States on understory shrubs in Vancouver, Washington in April 2010.\u00a0 We don\u2019t know a lot about this insect but we are beginning to tease out how it operates.<\/p>\n

\n \"green<\/strong><\/a>\n
Figure 1: Green alder sawfly larva (photo by Jim Kruse)<\/figcaption>\n <\/figure>\n

How do you identify this critter?
\n<\/strong>Adults emerge from overwintering sites in the soil or dead wood in the spring and lay eggs on expanding alder leaves.\u00a0 New larvae are very pale green and 2-3 millimeters long.\u00a0 Over time, as the larvae mature, they become a vibrant green (Figure 1).\u00a0 When fully grown larvae are about 15-18 millimeters long, a little more than \u00bd inch.\u00a0 The adults look like a small wasp, and the females (males have not been recorded in North America or the UK) have a black head and antennae.\u00a0 The middle (thorax) of the adult insect is black, sometimes with some yellow or brownish coloration; their legs reddish brown to black and abdomen black with the margins of the segments white to yellow (Figure 2).<\/p>\n

\n \"green<\/strong><\/a>\n
Figure 2: green alder sawfly adult (photo by Andrei Karankou)<\/figcaption>\n <\/figure>\n

Life history
\n<\/strong>A pre-pupal stage overwinters and pupation occurs in the spring.\u00a0 After the eggs hatch in the spring, larvae feed on alder leaves through the spring and early summer, then typically drop to the ground to pupate in the soil.\u00a0 In Europe and recently observed in Alaska, these insects have been reported to also burrow into rotten wood to pupate (Figure 3).\u00a0 Just another reason not to move firewood interstate.<\/p>\n

What about potential impacts?
\n<\/strong>Not much is known about how this insect will fare on red alder in western Oregon and Washington, as well as other species throughout these two states.\u00a0 In Alaska, this species has been feeding primarily on thinleaf alder (Alnus tenuifolia<\/em>).\u00a0\u00a0 There is some concern that the feeding of the green alder sawfly, woolly alder sawfly and the striped alder sawfly combined with stem cankers may lead to reduced nitrogen inputs by alders and perhaps alder mortality.<\/p>\n

\n \"green<\/a>\n
Figure 3: green alder sawfly pupal niches (photo by Jim Kruse)<\/figcaption>\n <\/figure>\n

In the Pacific Northwest, several insects feed on alder species so these may compete for host foliage and the additional feeding by the introduced sawfly may have a minor effect.\u00a0 However, the green alder sawfly begins feeding earlier in the spring than other species and could effectively outcompete native species if foliage becomes limited.\u00a0 Another concern is the native parasite\/predator complex: will these make the switch to the new invader?<\/p>\n

What to do?
\n<\/strong>Efforts by federal and state agencies will include trying to delimit the extent of the sawfly\u2019s distribution and encouraging more monitoring as well as research and education.\u00a0 The US Forest Service point person for this invasive insect is Kathy Sheehan, based in Portland.\u00a0 She is coordinating the effort to determine the distribution of the green alder sawfly in Oregon and Washington.\u00a0 They have already set up trapping sites throughout western Oregon in particular.\u00a0 Eradication is not a feasible option because of the widespread distribution of detections in Washington and Oregon.\u00a0 The fact this invader can potentially pupate in dead wood is another reason to manage the distribution of firewood and keep it local.<\/p>\n

The bright green larvae are distinct.\u00a0 If you are out and about in your forest, look for these critters on alder leaves and if you find any likely suspects contact Amy Grotta at the Extension office, 503-397-3462, Dave Shaw, OSU Extension Forest Health Specialist (dave.shaw@oregonstate.edu<\/a>) at 541-737-2845, or Kathy Sheehan (ksheehan@fs.fed.us<\/a>) at 503-808-2674.\u00a0 For more information, go to http:\/\/www.fs.fed.us\/r6\/nr\/fid\/invasives\/green-alder-sawfly.shtml<\/a>.<\/p>\n

References
\n<\/strong>Green Alder Sawfly.\u00a0 2010.\u00a0 Forest Health Protection, Pacific Northwest Region, USDA Forest Service.\u00a0 4 pages.<\/p>\n

New Pest in Alaska and Washington: The Green Alder Sawfly-Monsoma pulveratum<\/em> (Retizius).\u00a0\u00a0 2010.\u00a0\u00a0 Pest Alert.\u00a0\u00a0 USDA Forest Service State and Private Forestry Alaska Region.\u00a0 R10-PR-002.\u00a0 2 pages.<\/p>\n","protected":false},"excerpt":{"rendered":"

By Paul Oester and Dave Shaw, OSU Extension Service History A native of Europe, North Africa and the Near East, the green alder sawfly (Monsoma pulveratum) (Hymenoptera: Tenthredinidae) was first found in North America in eastern Canada in the early 1990\u2019s, then in Alaska in 2004.\u00a0 More recently, the green alder sawfly was identified in… Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":1783,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[55521],"tags":[3468,3469],"class_list":["post-81","post","type-post","status-publish","format-standard","hentry","category-forest-health-2","tag-forest-health","tag-invasives"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/dev.blogs.oregonstate.edu\/treetopics\/wp-json\/wp\/v2\/posts\/81","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/dev.blogs.oregonstate.edu\/treetopics\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/dev.blogs.oregonstate.edu\/treetopics\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/dev.blogs.oregonstate.edu\/treetopics\/wp-json\/wp\/v2\/users\/1783"}],"replies":[{"embeddable":true,"href":"https:\/\/dev.blogs.oregonstate.edu\/treetopics\/wp-json\/wp\/v2\/comments?post=81"}],"version-history":[{"count":13,"href":"https:\/\/dev.blogs.oregonstate.edu\/treetopics\/wp-json\/wp\/v2\/posts\/81\/revisions"}],"predecessor-version":[{"id":362,"href":"https:\/\/dev.blogs.oregonstate.edu\/treetopics\/wp-json\/wp\/v2\/posts\/81\/revisions\/362"}],"wp:attachment":[{"href":"https:\/\/dev.blogs.oregonstate.edu\/treetopics\/wp-json\/wp\/v2\/media?parent=81"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/dev.blogs.oregonstate.edu\/treetopics\/wp-json\/wp\/v2\/categories?post=81"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/dev.blogs.oregonstate.edu\/treetopics\/wp-json\/wp\/v2\/tags?post=81"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}