Juniper/Cedar

Pest Damage onJuniper/CedarNovember 21–30November 11–20November 1–10October 21–31October 11–20October 1–10September 21–30September 11–20September 1–10August 21–31August 11–20August 1–10July 21–31July 11–20July 1–10June 21–30June 11–20June 1–10May 21–31May 11–20May 1–10April 21–30April 11–20April 1–10March 21–31March 11–20March 1–10Plant ProblemCedar-Apple RustCedar-Hawthorn RustCedar-Quince RustSpittlebug, JuniperWeevil, Pales (Adults)BagwormBlack Vine Weevil, AdultLeafminer, ArborvitaeScale, FletcherScale, JuniperSpider Mite, SpruceCercospora BlightKabatina Tip BlightPhomopsis Tip BlightSalt InjuryWinter InjuryBlack Vine Weevil, 80 The Board of Regents of the University of Nebraska–Lincoln. All rights reserved.

Juniper/CedarPlant ProblemSigns/SymptomsTreatmentIn the autumn, greenish-brown,spherical to kidney shaped gallsappear on twigs. In the spring,the galls become gelatinous andbright orange-yellow.Avoid overhead irrigation.Plant resistant varieties.In the autumn, greenish-brown,spherical to kidney shaped gallsappear on twigs. In the spring,the galls become gelatinous andbright orange-yellow.Avoid overhead irrigation.Plant resistant varieties.Cigar shaped galls on smalltwigs; in the spring, gallsbecome gelatinous and brightorange-yellow.Avoid overhead irrigation.Plant resistant varieties.In May and June, shiny spittlelike masses develop mainly onnew growth; a pale nymph isembedded in each. Brownish,mottled adults remain onfoliage through the summer.Control is rarely needed, althoughthe nymphal spittle masses can bea nuisance. Natural enemies greatlyhelp to reduce spittlebug numbers.Dislodge spittle masses with a strongjet of water. In cases where foliage isyellowing, apply an insecticide.Small holes chewed in the barkof trunks, branches or twigs,which become covered withhardened resin. Seedling treesdie; larger trees show flaggingat branch tips.Remove stumps, or grind down andcover them with soil as they areprimary sites for weevil infestationfrom which adults emerge and attacktrees. To monitor, look for fresh resinor use sticky traps. Spray trees inspring when adults are present.Cedar-Apple RustCedar-Hawthorn RustCedar-Quince RustSpittlebug, JuniperWeevil, Pales (Adults)81 The Board of Regents of the University of Nebraska–Lincoln. All rights reserved.

Juniper/CedarPlant ProblemSigns/SymptomsTreatmentEarly in the season the bags arequite small and foliage appearsdesiccated and riddled withsmall holes. In late summer,bags are large, and severedefoliation occurs around them.Remove the previous year’s bags on thehost before May 1. Treat larvae whilebags are small, before July 1. Use Btor appropriate insecticides to conservenatural enemies. Later in the season,treat hosts with thorough coverage;effectiveness may be poor.Needles close to base of planthave numerous notches andfeeding scars. Foliage mayappear stressed, yellowed ordesiccated from larval feedingbelow-ground.Black vine weevils are active at night.Since adults crawl and cannot fly,pick off adults in the early morningon small host plants. Treat largerplantings in the evening with apersistent or systemic insecticidewith thorough coverage, especiallytoward the base.Tips of foliage turn uniformlybrown in the autumn. Affectedfoliage is hollow and containsfecal pellets and greenishlarvae, which overwinter inleaf mines and resume feedingin early spring.Tiny silvery-tan moths depositeggs on foliage in late spring intoearly summer; monitor with yellowsticky traps to properly time adultinsecticidal treatment. Treat with asystemic insecticide in the springto control larvae in leaf mines.In late spring, look for rounded,globular, brown “shells” (adultfemale scales) attached to twigs.Infested branches are yellowedand have sticky honeydew andsooty mold growth.Apply an insecticide or insecticidalsoap in early summer when newlyhatched nymphs (“crawlers”) haveemerged from beneath adult femalescales. Apply a systemic insecticide asa soil drench in late autumn or earlyspring to control older scales.Dirty-white, circular, flat scales orencrustations occur on needles.Branches and twigs turn yellowor die. In heavy infestationsentire plants can be killed.Prune out heavily infested and deadbranches. Employ cultural practicesthat reduce plant stress. Monitorfor newly hatched nymphs in June,and apply an oil spray, insecticidalsoap or insecticide. Apply a systemicinsecticide in May as a foliar spray.BagwormBlack Vine Weevil, AdultLeafminer, ArborvitaeScale, FletcherScale, Juniper82 The Board of Regents of the University of Nebraska–Lincoln. All rights reserved.

Juniper/CedarPlant ProblemSigns/SymptomsTreatmentStippling of needles becomesevident on older foliage inearly spring. By early summer,infested portions turn yellowor brown and appear dried out.Dirty, fine webbing is evident.Monitor regularly for early damagein April. Treat infestations withvigorous sprays of an insecticidalsoap or an insecticide/miticide.Thorough coverage is important, andre-treatment is often necessary. Bymid summer, infestations naturallydecline; do not treat.First appears on inner branchneedles and in lower portions oftree. Needles are dull brown orred and eventually drop. Small,hair-like fungal structures arevisible on dead needles.Prune out affected areas. Improve aircirculation. Avoid over-fertilization.Avoid overhead irrigation. Plantresistant varieties. Apply foliarfungicide between early June andearly July.Terminal 2 to 6 inches ofbranches turn dull green andthen red or yellow. Small, ashgray to silver lesions dotted withblack fruiting bodies are presentat the base of the needle, tipseventually turn brown and drop.Prune out affected areas. Improve aircirculation. Avoid over fertilization.Avoid overhead irrigation. Plantresistant varieties.Foliage is dull red or brown;foliage eventually turns anash-gray. Small gray lesions onthe foliage; small, black fruitingbodies develop within the lesion.Branch tips may become girdled.Repeated blighting can causewitches’ broom, discoloration offoliage, stunting and plant death.Prune out affected areas. Improve aircirculation. Avoid over fertilization.Avoid overhead irrigation. Plantresistant varieties. Apply foliarfungicide at bud break and repeataccording to label instructions.Foliage is yellow or brownwith damage often closest toroads, sidewalks or other areaswhere salt is applied. Oftenappears in the spring, oncetemperatures begin to increase.Leaf or twig dieback.Prune out affected area.Spider Mite, SpruceCercospora BlightKabatina Tip BlightPhomopsis Tip BlightSalt Injury83 The Board of Regents of the University of Nebraska–Lincoln. All rights reserved.

Juniper/CedarPlant ProblemSigns/SymptomsTreatmentFoliage is reddish-brown withdamage at terminal ends offoliage (commonly needles).Damage mostly on outerportion of the branches andoften more severe on side ofthe plant facing the wind.Prune out affected area.Mature larvae are legless,creamy-white, over one-half inchlong and have a brown head.Their feeding on roots and incrowns cause wilting, dessicationor death of host plants.In spring, first confirm the presenceof actively feeding larvae, thendrench the soil around host plantswith a water-soluble insecticideaccording to label directions.Parasitic nematodes are practicaland effective in moist conditions forsingle shrubs or potted plants.Winter InjuryBlack Vine Weevil, Larvae84 The Board of Regents of the University of Nebraska–Lincoln. All rights reserved.

KEY: fruit flower branches leaves trunk crown roots September 2 1–30 September 1 1–20 September 1 – 10 June 2 1–30 June 1 1–20 June 1 –