lace bugs - virginia tech · 2016 virginia tech 3104 -1581(ento204np) lace bugs eric day,...

2016 Virginia Tech 3104-1581 (ENTO-204NP)

LaceBugs

EricDay,DepartmentofEntomology,VirginiaTechDescription: Lace bug damage is first noticed as yellow spots on the upper leaf surfaces ofaffected plants. Lace bugs actually feed on the undersides of leaveswith their piercing-suckingmouthparts,butbecause theykill surroundingcellsas they feed, theycause theyellowspots toappearonupper sidesof the leaves.The firstyellowspots thatappeararevery similar tomitedamage,butthespotsmadebylacebugsaremuchlarger.Whenfeedingdamagebecomessevere,the leaves take on a gray, blotchedappearanceorcanturncompletelybrown.Aslacebugs feed theyproducebrownvarnish-likedroppingsthatspottheundersideoftheleaves. These droppings further distinguishlace bug damage from mite damage. Whenlarge numbers of lace bugs are present castskins can be found attached to the leaves.Hemiptera:TingidaeHosts include Azalea, rhododendron,sycamore, broad-leaved evergreens, andmanydeciduoustreesandshrubs.Identification:Adultlacebugsareabout3to6 mm (1/8"- 1/4") long with a netlikepatternon thewings. In addition, thewingsare dotted with brown and black. Theimmature stages, called nymphs, are similarexcept they are smaller and often havespines. The eggs are small but are easily distinguished by their elongate and cylindrical shape.Theyresemblesmallblacksmokestacksattachedtotheundersidesofthe leaf.Lacebugsare intheorderHemiptera,family,Tingidae.LifeCycle:Ondeciduousplants,adultlacebugsoverwinterinprotectiveplacesonthehost,suchasbarkcrevicesandbranchcrotches,orontheground in leaf litter.Theyendtheirhibernationjustasspringgrowthstarts.Theyattachtheireggstotheundersidesoftheleavesoftenalongthemidribs,sometimescoveringthemwithablackvarnish-likecoating.Theeggswillstayattachedtotheleaveslongaftertheyhavehatchedandcanberecognizedbynotingifthetopshaveopenings.The nymphs complete their life cycles quickly and one to several generations can occur in oneseason;usually,therearetwogenerations.Somelacebugscancompleteagenerationinasfewas30days.Usually,bytheendofthesummer,alllifestagescanbefoundonahost.

On broad-leaved evergreens, lace bugsoverwinter as eggs on the undersides of leaves.Eggs hatch inMay in Virginia and two ormoregenerations may occur during the growingseason.Control: Lace bug control requires carefulmonitoringearlyintheseason.Controlshouldbeapplied when insects are found on the foliage,either on adults on deciduous plants or ongroupsofnymphsonbroad-leavedevergreens.Itisvery importanttospraytheundersidesof theleavesbecausethisiswheretheyfeed.ChecktheVirginia Pest Management Guide for specificcontrolrecommendations.SomeImportantLacebugsinVirginiaAzaleaLaceBug.Trytocontrolthefirstgenerationfrommid-Maytomid-June;twospraysmaybenecessary.TwogenerationsofazalealacebugsoccurinVirginiaperyear.ThesecondbroodbuildsuptohighpopulationsinAugustandSeptemberanddamagecanbesevereonazaleasplantedinfullsun.Insomecases,theleavesturncompletelybrownandareheavilyspottedwithdroppingsbytheendofthesummer.Ifpossiblemoveshrubtoashadylocationinlandscape.Rhododendron Lace Bug. Treat in May or June to control the first generation. Rhododendronsgrowing in full sunmayhavea yellowishappearance from feedingby rhododendron lacebugs.Damageisnotaspronouncedasforazalealacebugs,buttreatmentissometimesneeded.SycamoreLaceBug.TreatinJuneorwhen nymphs appear; a secondtreatmentmaybeneeded.Thisisanimportant pest of sycamore,especiallyonstreetandshadetrees.Multiple generations occur eachyear and defoliation may occur inseverecases.Replaces:VCE3104-1581