2016 Virginia Tech 3104-1562 (ENTO-210NP)

RedneckedCaneBorer

DouglasG.Pfeiffer,DepartmentofEntomology,VirginiaTechIntroduction:Theredneckedcaneborer,Agrilusruficollis (F.), isabuprestidbeetlethat infestswildandcultivatedblackberriesandraspberriesintheeasternstatesfromCanadatotheGulfofMexico.Adultsareabout6-7mm (1/4 inch) long,with an iridescent copperypronotum.A related species,Agrilus rubicola,mayoccurconcurrently.Thisspeciesisuniformincolor,rangingfromcopper-coloredtoiridescentgreen.Ongalledplants,thereislesslivevegetativegrowthandmoredeadwood.Thereisoftenreducedberrysizeandnumber,aswellasvegetativegrowthwithincreasingnumberofgallsperplant.Affectedcanesmaynotproducefruit.Canesweakenedbygallsaremoresubjecttowinterinjury.Biology: Adults are present from May to August, or late April to early June, depending on the region.Females lay white spherical eggs on the trunk, andproduce a yellow viscous material from the ovipositor,which issmoothedover intoacovering,before fadingtowhiteorgrey.Larvaeexit theeggdirectly intotheplant,never becoming exposed, and so are impervious tosprays. Young larvae are restricted to the cambium,circling the cane 3-4 times in a close spiral, girdling theprimocane, and producing gall-like swellings. As larvaegrow,theyextendfeedingdeeperintowoodandpith,andstraightening the spiral and heading usually toward thedistalendof thecane (tunnelsmayextend15cmbelowto64cmabovethegall).Larvaereachalengthof12mm,andhaveapairofhorn-likeprojectionsontheposteriorend. The larvae are white and legless, with a flattenedhead (the family is often called flatheadeded borers).Larvaewinterinthecane,andinMarchcreateapupalchamber.ThepupaisformedinlateApril.Thepupalperiodlasts20-40days.Whentheadult leavesthepupalskin, itremains inthetunnel forabout10daysbefore chewing a D-shaped emergence hole. Adults feed on foliage for several days before beginningoviposition. They are most easily found on the plants on warm sunny days. There is one generationannually.ControlChemicalcontrol:Afterleaffallorduringwinterpruning,notegalls.Ifmorethan10%oftheprimocanesare infested, or if the number of primocanes expected to be pruned off is exceeded, a spray in justified.Examineprimocanes foradults twiceweekly,beginningat thebeginningofbloom.Damage isminimizedwhenmalathion is applied at intervals of 7-12days from the time the first beetles appear (early tomidMay) until early June (last emergence). Often two sprays will suffice, just before bloom and about twoweekslater(ortheendofbloom,whicheverislater).Spraytowardthebaseofcanes,avoidingareaswithanyresidualblooms.Biological control: This species is occasionally parasitized by Barichneumon sp. and other species.Mortalitymaybequitehigh,butthenormaldegreeofsuccessfulbiologicalcontrolisunknown.

Culturalcontrol:Removegalledcanesindormantseasonorearlyspring.Thisismosteffectiveifnearbywildhostsareeliminated,andalsomoreeffectiveinopensettings(wildbramblesinnearbywoodsprovidea source ofwild beetles). Summer pruning alsomay provide a substantial reduction in rednecked caneborerinfestation,sincebythetimenewshootsappear;theyhaveescapedmuchoftheovipositionperiodofredneckedcaneborer.OtherInformationJohnson,D. T. 1992. Rednecked cane borer. p. 75. In Ellis,M. A., R.H. Converse, R.N.Williams andB.Williamson.Compendiumofraspberryandblackberrydiseasesandinsects.APSPressJohnson,D.T.1992.Redneckedcaneborergallingaffectsblackberrygrowthandyield.J.Am.Soc.Hortic.Sci.117:780-783.Johnson, D. T. and R. L. Mayes. 1989. Biology and control of the rednecked cane borer, Agrilus ruficollis (F.)(Coleoptera:Buprestidae),onblackberriesinArkansas.J.Entomol.Sci.24:204-208.Mundinger,F.G.1941.Twobuprestidcane-borersofbrambleswithexperimentsoncontrol.J.Econ.Entomol.34:532-537.Walton,R.R.1951.Controlofthered-neckedcaneboreronprostratebramblesbysummerpruning.J.Econ.Entomol.44:950-954.Replaces:VCE3104-1562