{{Short description|Species of sawfly}} {{Speciesbox | image = | image_alt = | image_caption = | genus = Tomostethus | species = multicinctus | authority = (Rohwer, 1909) }}
'''''Tomostethus multicinctus''''', the '''brownheaded ash sawfly''', is a species of sawfly in the family Tenthredinidae that is native to southern Canada and the eastern United States. Adults of this species resemble wasps and the larvae feed on the leaves of ash trees.
==Description== The brownheaded ash sawfly is commonly found in the eastern United States and southern Canada. It is a pest to green or red ash and white ash trees although any species of ash is vulnerable; female insects lay groups of eggs in slits in the leaflets of emerging leaves in late spring.<ref name="Texas"/><ref name="Colorado"/><ref>{{cite book|last1=Cranshaw|first1=Whitney|title=Garden Insects of North America: The Ultimate Guide to Backyard Bugs|date=2015|publisher=Princeton University Press|isbn=978-1-400-86678-6|page=78|url=https://books.google.com/books?id=RITYBQAAQBAJ&dq=tomostethus+multicinctus}}</ref> The larvae are greenish or yellow-white, and they grow to between {{convert|14|and|20|mm|in|1|abbr=on}} long.<ref name="Eastern">{{cite book|last=United States Forest Service |date=1985 |title=Insects of Eastern Forests |url=https://books.google.com/books?id=OSgoSNkp0U0C&pg=PA408 |publisher=U.S. Department of Agriculture |page=408 }}</ref> At first the larvae eat the central part of the leaflets, making pinpoint holes, but they feed voraciously and grow rapidly, eating all the leaf tissue except for the veins. A heavy infestation can cause complete defoliation of the tree in a week, but there is only one generation of larvae each year and new leaves soon grow.<ref name="Baker1972">{{cite book|author= Baker, Whiteford Lee |title=Eastern Forest Insects|url=https://archive.org/details/easternforestins1175bake |year=1972 |publisher=U.S. Forest Service |pages=[https://archive.org/details/easternforestins1175bake/page/463 463]–464}}</ref> High winds can detach the larvae from the leaves.<ref name="Colorado">{{cite web|url=http://extension.colostate.edu/topic-areas/insects/brownheaded-ash-sawfly-5-586/ |title=Brownheaded Ash Sawfly |last=Cranshaw |first=W.S. |website=Colorado State University |access-date=April 18, 2017 |url-status=live |archiveurl=https://web.archive.org/web/20170418082823/http://extension.colostate.edu/topic-areas/insects/brownheaded-ash-sawfly-5-586/ |archivedate=April 18, 2017 }}</ref> When the larvae shed their skin for the final time, the skin stays attached to the leaves, while the larvae fall to the ground,<ref name="Colorado"/> where they create cocoons in the topsoil and spend the winter as prepupae.<ref>{{cite book|last=Cooper Craighead |first=Frank |date=1950 |title=Insect Enemies of Eastern Forests |url=https://archive.org/details/insectenemiesofe657crai |publisher=U.S. Department of Agriculture |page=[https://archive.org/details/insectenemiesofe657crai/page/581 581] }}</ref> They pupate in the cocoon in early spring,<ref name="Colorado"/> emerging as adult insects when the ash leaves begin to unfurl.<ref name="Baker1972"/> Large numbers of the insects are often seen swarming around ash trees at this time.<ref name="Colorado"/>
The adults are black and do not sting,<ref name="Colorado"/> like other sawfly species. Sawflies receive their name because the females have a structure that resembles a saw on the tip of their abdomen.<ref name="Texas">{{cite web |url=http://texasinsects.tamu.edu/cimg325.html |title=Sawfly |website=Texas A&M University Entomology |access-date=April 18, 2017 |url-status=dead |archiveurl=https://web.archive.org/web/20160811104544/http://texasinsects.tamu.edu/cimg325.html |archivedate=August 11, 2016 }}</ref>
==Predators and control== Parasitic wasps are known to eat the larvae.<ref name="Colorado"/> Two red-eyed vireo were witnessed bashing the larvae against a twig up to eighteen times, and then consuming them with multiple swallows without any noise.<ref name="Research"/> Other birds observed consuming the larvae in the study were a rose-breasted grosbeak, an English sparrow, and two catbirds.<ref name="Research">{{cite web |url=https://sora.unm.edu/sites/default/files/journals/auk/v050n04/p0451-p0452.pdf |title=General Notes |date=1933 |website=Searchable Ornithological Research Archive |access-date=April 18, 2017}}</ref>
A hose or soapy water can be used to loosen the larvae from a tree. Most insecticides for use in a garden can kill the larvae. Practices to get rid of the larvae must be completed in the beginning of their infestation.<ref name="Colorado"/>
==References== {{Reflist|30em}}
{{Taxonbar|from=Q14452974}}
Category:Hymenoptera of North America Category:Tenthredinidae Category:Insects described in 1909 Category:Taxa named by Sievert Allen Rohwer