Azalea and rhododendron lace bug
134 host plants
Last updated
Data Coverage 3 of 6 dimensions
On rhododendron and azalea leaves you will notice pale stippled areas on upper surfaces where lace bugs have sucked plant juices, creating an overall bleached appearance. Look at undersides of damaged leaves for brown varnish-like spots (concentrated cast skins and feces) and the distinctive tan and brown lace-winged adults. Heavy infestations turn entire leaves pale yellow or brown.
Spray undersides of leaves thoroughly with water in early June to dislodge nymphs. Apply insecticidal soap or horticultural oil when temperatures stay below 85F; repeat every 10 days as needed. Encourage parasitoid wasps and predatory mites by avoiding broad-spectrum insecticides. Dense shade reduces populations naturally. Treat only if infestations yellow large canopy portions.
Quick Reference
Host Plants
134
GDD₃₂ Emergence (est.)
963
Peak Activity
April-May hatching; multiple generations through September
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Mar 22, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Seattle / UW | 1,013 | Emergence (est.) | — | — |
| Issaquah / East King | 1,006 | Emergence (est.) | — | — |
| Olympia / Tumwater | 952 | Pre-season | Emergence (est.) | 11 |
| Bellingham / Whatcom | 948 | Pre-season | Emergence (est.) | 15 |
| Kent / Auburn | 942 | Pre-season | Emergence (est.) | 21 |
| Sequim / Rain Shadow | 924 | Pre-season | Emergence (est.) | 39 |
| Tacoma / Puyallup | 921 | Pre-season | Emergence (est.) | 42 |
Source: UMD IPMnet catalog: 214 GDD₅₀. UMass Extension: begin scouting at 120+ GDD₅₀ (March 1 start). Previous enrichment value of 156 was from an Oregon State research paper (Rosetta) using base 10.2°C (50.4°F) for egg development, not base 50°F - a BASE TEMPERATURE ERROR. Adopted catalog value of 214 GDD₅₀. CORRECTED 2026-03-20. Sources: UMD: extension.umd.edu; UMass: UMass Extension. Additional sources: Rutgers: plant-pest-advisory.rutgers.edu (118-372 GDD₅₀). About GDD₃₂ →
Host Plants (134)
Pyracantha coccinea Firethorn Pyracantha koidzumii Formosan Firethorn Rhododendron 'Purple Gem' Purple Gem Rhododendron Rhododendron airy Rhododendron, airy Rhododendron alabamense Alabama Azalea Rhododendron alice Alice Rhododendron Rhododendron anah Rhododendron, anah Rhododendron anna Rhododendron, anna Rhododendron april Rhododendron, april Rhododendron arboreum subsp. cinnamomeum Cinnamon Rhododendron Rhododendron argosy Argosy Rhododendron Rhododendron augustinii Augustine Rhododendron Rhododendron auriculatum No common name (R. auriculatum) Rhododendron beauty Rhododendron, beauty Rhododendron bibiani Bibiani Rhododendron Rhododendron blue Rhododendron, blue Rhododendron boule Rhododendron, boule Rhododendron bow Rhododendron, bow Rhododendron bric Rhododendron, bric Rhododendron bureavii Bureau Rhododendron Rhododendron campylocarpum subsp. coloxanthum Coloxanthum Rhododendron Rhododendron catawbiense Catawba Rhododendron Rhododendron cheer Cheer Rhododendron Rhododendron chevalier Rhododendron, chevalier Rhododendron christmas Rhododendron, christmas Rhododendron cinnabarinum Cinnabar Rhododendron Rhododendron concinnum Concinnum Rhododendron Rhododendron cotton Rhododendron, cotton Rhododendron crater Rhododendron, crater Rhododendron crest Crest Rhododendron Rhododendron cunninghams Rhododendron, cunninghams Rhododendron cynthia Cynthia Rhododendron Rhododendron daphnoides Daphnoides Rhododendron Rhododendron dauricum Dauricum Rhododendron Rhododendron davidsonianum Davidsonianum Rhododendron Rhododendron day Rhododendron, day Rhododendron deciduous Rhododendron, deciduous Rhododendron defines Rhododendron, defines Rhododendron delaware Rhododendron, delaware Rhododendron dora Rhododendron, dora Rhododendron dreamland Dreamland Rhrododendron Rhododendron el Rhododendron, el Rhododendron elisabeth Rhododendron, elisabeth Rhododendron elizabeth Elizabeth Rhododendron Rhododendron falconeri subsp. falconeri Falconer Rhododendron Rhododendron fantastic Fantastic Rhododendron Rhododendron formosum var. formosum Formosum Rhododendron Rhododendron forrestii subsp. forrestii Forrest Rhododendron Rhododendron fortunei subsp. discolor Fortune Discolor, Discolor Rhododendron Rhododendron frilly Rhododendron, frilly Rhododendron gartendirektor Rhododendron, gartendirektor Rhododendron girards Rhododendron, girards Rhododendron goldflimmer Goldflimmer Rhododendron Rhododendron grace Rhododendron, grace Rhododendron groenlandicum Labrador-tea, Labrador Tea Rhododendron haematodes subsp. haematodes Haematodes Rhododendron Rhododendron hallelujha Hallelujah Rhododendron Rhododendron hanceanum Hanceanum Rhododendron Rhododendron hardijzer Rhododendron, hardijzer Rhododendron harry Rhododendron, harry Rhododendron hino Rhododendron, hino Rhododendron hinode Rhododendron, hinode Rhododendron hippophaeoides var. hippophaeoides Hippophaeoides Rhododendron Rhododendron hodgsonii Hodgson Rhododendron Rhododendron honourable Rhododendron, honourable Rhododendron horizon Rhododendron, horizon Rhododendron hotei Hotei Rhododendron Rhododendron irroratum Irroratum Rhododendron Rhododendron jock Jock Rhododendron Rhododendron johnstoneanum Rhododendron, johnstoneanum Rhododendron keiskei Keiskei Rhododendron, Keisuki Rhododendron Rhododendron ken Rhododendron, ken Rhododendron kiusianum Kiusianum Azalea, Kyushu Azalea Rhododendron lacteum Lacteum Rhododendron Rhododendron lees Rhododendron, lees Rhododendron lems Rhododendron, lems Rhododendron lights Rhododendron, lights Rhododendron loderi Rhododendron, loderi Rhododendron luteiflorum Luteiflorum Rhododendron Rhododendron lutescens Lutescens Rhododendron Rhododendron luteum Pontic or Pontica Azalea Rhododendron macabeanum Macabeanum Rhododendron Rhododendron macrophyllum Pacific Rhododendron Rhododendron moonstone Moonstone Rhododendron Rhododendron mrs Rhododendron, mrs Rhododendron mucronulatum Rhododendron, mucronulatum Rhododendron myrtifolium Myrtifolium Rhododendron Rhododendron niveum Niveum Rhododendron Rhododendron northern Rhododendron, northern Rhododendron occidentale Western Azalea Rhododendron orbiculare subsp. orbiculare Obiculare Rhododendron Rhododendron orchid Rhododendron, orchid Rhododendron oreotrephes Oreotrephes Rhododendron Rhododendron oudijks Rhododendron, oudijks Rhododendron pachytrichum Pachytrichum Rhododendron Rhododendron peekaboo Peekaboo Rhododendron Rhododendron pink Rhododendron, pink Rhododendron pioneer Rhododendron, pioneer Rhododendron pjm P.J.M. Rhododendron Rhododendron point Rhododendron, point Rhododendron ponticum Rhododendron, ponticum Rhododendron president Rhododendron, president Rhododendron prinophyllum Roseshell Azalea, Pinkshell Azalea Rhododendron prunifolium Plumleaf Azalea Rhododendron quinquefolium Quinquefolium Azalea Rhododendron racemosum Racemosum Rhododendron Rhododendron ramapo Ramapo Rhododendron Rhododendron rosamundi Rosamundi Rhododendron Rhododendron roseum Rhododendron, roseum Rhododendron rosy Rhododendron, rosy Rhododendron roxieanum var. oreonasters No common name Rhododendron rubiginosum Rubiginosum Rhododendron Rhododendron sappho Sappho Rhododendron Rhododendron scarlet Rhododendron, scarlet Rhododendron schlippenbachii Royal Azalea Rhododendron serpyllifolium Wild Thyme, Azalea Rhododendron serpyllifolium var. albifolrum White Wild Thyme, Azalea Rhododendron sinofalconeri Sinofalconer Rhododendron Rhododendron sinogrande Sinogrande Rhododendron Rhododendron smirnowii Smirnow Rhododendron Rhododendron snow Rhododendron, snow Rhododendron stenopetalum Rhododendron, stenopetalum Rhododendron taurus Taurus Rhododendron Rhododendron temple Rhododendron, temple Rhododendron thomsonii subsp. thomsonii Thomson Rhododendron Rhododendron tri Rhododendron, tri Rhododendron trilby Trilby Rhododendron Rhododendron unique Unique Rhododendron Rhododendron vulcan Vulcan Rhododendron Rhododendron wardii Ward Rhododendron Rhododendron white Rhododendron, white Rhododendron wiltonii Wilton Rhododendron Rhododendron winsome Winsome Rhododendron Rhododendron yakushimanum Yak Rhododendron