Black ants, attracted by the honeydew, appear near scales and attack the natural predators of the scales. The azalea bark scale, Eriococcus azaleae Comstock, can be found on a variety of hosts grown in nurseries and landscapes including azalea, rhododendron, andromeda, hawthorn, poplar, willow, and most recently, it has been found infesting blueberries in the Pacific northwest. Vitax Plant Guard Pest & Disease Control, Bug Clear for Fruit and Veg) can give good control of scale insect nymphs. . Azalea bark scale infestation. This sap-sucking scale can cause serious harm to your favorite Azalea or Rhododendron. The azalea bark scale survives the winter in the immature stage. Can I use Pivot 10 for azalea bark scale?Cottony maple/taxus scale? Soft Scales Found on Trees and Shrubs - The following are examples of commonly found scale insects that infest deciduous, broadleaf, and evergreen plants. Ecofective Bug Control, RHS Bug and Mildew Control, SB Plant Invigorator and Westland Resolva Natural Power Bug & Mildew). They feed by sucking sap and some can weaken host plants, many excrete a sticky substance (honeydew), which allows the growth of sooty moulds. For biology, life history, monitoring and management. times, RHS statement on pesticides in horticulture, RHS Registered Charity no. Masses of the white, waxy covering will be apparent in an infestation. Imagine a downpipe on your house which freezes and then splits. Replant at the correct level. Prevention and control of azalea bark scale requires proper plant maintenance and identifying early signs of scale attack. The immature crawlers emerge over the course of 2 weeks. They insert the stylet into the leaves and twigs of rhododendron, causing damage and depleting the plant’s health. While leaf spots can be controlled with a fungicide, root and crown rot can be prevented to some extent by planting rhododendrons in well drained soil. Protect your garden If azalea bark scale is found, Michigan State University Extension recommends spraying infested plants with a 2 percent concentration of a horticultural oil in mid-July. Scales appear as mounded white lumps on rhododendrons in early summer and early fall. They are mostly 1-6mm (less than ¼in) long, although wisteria scale, Eulecanium excrescens, can be up to 10mm (about ½in), and vary in shape and colour. The insect releases a liquid and sugar mixture called honeydew. Eggs are laid in late April and a new batch of this azalea pest hatches in about three weeks. Vitax Plant Guard Pest & Disease Control, Bug Clear for Fruit and Veg) can give good control of scale insect nymphs. All Rights Reserved. I purchased some horticulture oil this morning from Lowes but I'm skeptical about it's effectiveness of getting rid of mature bark scale. Introduction 2.1. The azalea bark scale also feeds on ornamental cherry, poplar, willow and hawthorn trees. All species have a shell-like waxy covering over their bodies when mature. The crawlers emerge in about three weeks. If they're not moving around, small, fuzzy, white caterpillars might be one of the thousands of species of scale. If there are no yellowing leaves, no treatment is necessary. … Recommended treatment may depend on their location. An alternative treatment for azalea bark scale is a … Hosts include andromeda, azalea, rhododendron, hawthorn, poplar, willow, and most recently blueberries. Symptoms of their sucking include honeydew, sooty mold, and considerable leaf yellowing and die back. Growing Success Winter Tree Wash) can be used. Treatment with horticultural oil can help. Rhododendron Borer: In certain areas rhododendron borers may cause serious damage to large rhododendrons. The female azalea bark scale lays her eggs in the spring in a white, waxy coating she produces. A large infestation can cause severe damage or kill the plant. Watching the white mounds during hatching season will reveal the small crawlers moving along the plant searching for a spot to suck the sap. Adult scale insects are usually covered in waxy shell-like cover. 020 3176 5800 Lace bugs/Spider mites. Scale insects on bay. Plant oil and fatty acid products are less likely to affect larger insects such as ladybird adults, Plant invigorators combine nutrients to stimulate plant growth with surfactants or fatty acids that have a physical mode of action (e.g. Feed and water the plant and it will probably pick up. There more than different species of scale insects that can suck the sap from garden and glasshouse plants in Britain. Bug Clear Gun for Fruit & Veg, Neudorff Bug Free Bug and Larvae Killer), fatty acids (e.g. See "Scale insect" in: Common Landscape Pests This can be colonised by a black non-parasitic fungus known as sooty mould, Some scale insects deposit their eggs under a covering of white waxy fibres in early summer, Where possible tolerate populations of scale insects. Leaves on affected branches wilt as affected branches die. Scale insects can be found on a wide range of ornamental plants, fruit trees and bushes grown out of doors. ; Will Zylam Liquid Systemic Insecticide work on the Crape Myrtle Bark Scale? 4. Scale treatment options . Rhododendrons and azaleas are some of the most popular spring-flowering shrubs in the landscape, and healthy plants can give years of pleasure. The eggs are often laid under the protection of this shell but with the cushion scales (eg Pulvinaria species) the eggs are deposited outside the scale under a mass of white waxy fibres. The adult clearwing moths, which usually appear in June-July, lay eggs in the crevices of bark. Not all scale insects affect the growth of plants and so they do not necessarily require control, Adult scales and egg masses can be removed when seen but this may not reduce large populations, For scales on deciduous plants including edible fruits, a plant oil winter wash (considered organic e.g. Bug Clear Gun for Fruit & Veg, Neudorff Bug Free Bug and Larvae Killer), fatty acids (e.g. Rhododendron Rhododendron is a large evergreen shrub (growing up to 8m tall) that was introduced to Ireland as an ornamental plant in the 18th Century from Asia and north-west China. A few years ago, some developed azalea bark scale infestations. Horticultural oil will give control if thorough coverage is achieved on the undersides of leaves. (This was diagnosed from a photo I sent to your service a couple of years ago.) A: That crusty growth might look like a fungus or mold, but it’s actually a bug called azalea bark scale. E. Bark Split This can be a serious problem with smellies in cold winters. Identifying azalea bark scale early gives an advantage in treatment. Scales are only vulnerable to insecticides during the immature phase before they have created the white coating. She has training in landscaping and a certification in medicinal herbs from a botanical sanctuary. Rhododendron is suffering from lack of water: often due to competition from tree roots. Azalea Bark Scale (Erlococcus azalene) Recognition and Life Cycle Females are approximately 1/8-inch long and covered with a white, waxy egg sac. Q&A related to Azalea Bark Scale. The insect in the picture insect looks like a mealybug, though Azalea Bark Scale can have a similar appearance. Kit Arbuckle is a freelance writer specializing in topics such as health, alternative medicine, beauty, senior care, pets and landscaping. The "bumps" may be brown or marbled brown and white. Insecticidal soap sprays during the growing season will help control crawlers and adults of soft scales, like the azalea bark scale. There are various other rhododendron diseases, like leaf spots, and root and crown rot. 3. An oil spray applied after the crawlers emerge is usually very effective in controlling azalea bark scale, but keep checking each year and spray again when necessary. Aim of this advice This document provides best practice management guidelines on the control of Rhododendron ponticum and Cherry Laurel (Prunus laurocerus) on the island of Ireland. Rhododendron scale disease is actually caused by an insect, Eriococcus azaleae, commonly called azalea bark scale. Dead bark falls off the cankered area. The female dies as the eggs grow. The adult phase females typically stay in one place on woody plant parts, while the winged males suck on the leaves. Dead scales may remain on stems for a year or more. I think they are Azalea Bark Scale. The crawlers like to attach to the bark and feed in crevices and branch forks. The success of any treatment can be gauged by the extent to which new growth remains free of scale insects, Pesticides for gardeners (pdf document) A scale infestation is indicated by sooty mold on leaves, yellowing of leaves, and twig dieback. Scales are only vulnerable to insecticides during the immature phase before they have created the white coating. Copyright Leaf Group Ltd. // Leaf Group Lifestyle. A black, sooty mold covers the plant where it grows on the honeydew. Spray the plants thoroughly, so that the soap spray drips or “runs off” from the upper and under sides of leaves, twigs, and plant stems. To treat, eliminate the insects and prune any dead or dying parts of the plant. Azalea bark scale (Eriococcus azaleae) Lecanium scale (Lecanium spp.) They could also be mealy bugs, a scale-like insect pest with visible legs that doesn't move around much. Some species also produce white, waxy egg masses on stems or the undersides of leaves, this can be mistaken for mealybug or woolly aphid. Azalea bark scales overwinter on older twigs and branches, under a white, felt-like egg sac about 6-12 mm in diameter. The worst effects can arise when out of season frosts strike just when the sap is rising. Scale insects on indoor plants can breed all year round and so there is no best time of year to treat. With grape vines, peel away the loose outer bark to expose the scales before treatment Organic sprays, such as natural pyrethrum (e.g. Eggs are laid in the spring and hatch from late-June to mid-July. ).It has been reported in the Eastern US, as well as Belgium and Russia. Do not use membrane and bark as rhododendrons dont like this. Thanks! Join the RHS today and support our charitable work, Keep track of your plants with reminders & care tips – all to help you grow successfully, For the latest on RHS Shows in 2020 and 2021, read more, RHS members get free access to RHS Gardens, Free entry to RHS members at selected times », Reduced prices on RHS Garden courses and workshops, General enquiries Azalea bark scale. Rhododendron is starved. Affected shrubs may be covered with sooty mold or appear as white, cottony masses within the forks of branches. It affects rhododendron family plants, including azaleas. Each species has a different host range and life cycle. Garden Guru Mike Westphal explains how to treat and prevent crepe myrtle bark scale. RHS members can get exclusive individual advice from the RHS Gardening Advice team. Bark scales. Note that dead scales can remain firmly attached to the plants. Identifying azalea bark scale early gives an advantage in treatment. Members of the rhododendron family, azaleas are hardy flowering shrubs with large, colorful flowers. Beneficial insects, such as wasps, control scale population. After eggs hatch the larva bores into branches and … The life cycle of scales always includes an egg, immature and adult phases. The adult females (1/8 inch) with their white egg sacs are most noticeable in May and June. --Sarah in Drexel Hill, PAA. Solabiol Bug Free, Doff Greenfly & Blackfly Killer) or plant oils (e.g. Rhododendron scale disease is actually caused by an insect, Eriococcus azaleae, commonly called azalea bark scale. 1) Azalea bark scale, Eriococcus azalea. This can control the overwintering scale nymphs in December-January when the plants are fully dormant, With grape vines, peel away the loose outer bark to expose the scales before treatment, Organic sprays, such as natural pyrethrum (e.g. The adult phase females typically stay in one place on woody plant parts, while the winged males suck on the leaves. What should I do? The immature scales feed on the newer growth of the rhododendron. Black ants, attracted by the honeydew, appear near scales and attack the natural predators of the scales. These branches should be removed and destroyed. the RHS today and get 12 months for the price of 9. There are two generations each year in Maryland. The symptoms of rhododendron scale disease include a change in color, poor growth, damaged foliage and a decline in health. This wax covers the entire body. These are the outer coverings of scale insect, Large populations may result in poor growth, Some species of scale insect excrete honeydew, which accumulates on the upper leaf surfaces. See: Azalea (Rhododendron)-Azalea bark scale. They insert the stylet into the leaves and twigs of rhododendron, causing damage and depleting the plant’s health. Plant rhododendrons in shade to maximize the activities of beneficial insects. Pest description and crop damage Lecanium scales overwinter on twigs and branches under a hard, helmet-like, reddish-brown covering, which is about 6-8 mm in diameter. Scraping the scales off of the rhododendron effectively eliminates them. The adults are sedentary but newly-hatched nymphs crawl actively over the plant surface and spread the infestation. Bug Clear Ultra) is also available. Female azalea bark scales lay their eggs in midspring, dotting azalea plants with what appear to be 1/10-inch-diameter white spots. This is a pest that generally does not kill hosts, rather it causes aesthetic damage. Rhododendron scales feed on the sap of the plant. Mon – Fri | 9am – 5pm, Join the RHS today and support our charity. Eriococcus azaleae. Biological control suppliers (downloads pdf). https://www.giroudtree.com Azalea Bark Scale can destroy beautiful Azalea shrubs. Unhealthy and weak plants sustain more injury from scale insects than strong plants. Females cover themselves with wax and eggs, crawlers and females beneath the wax are reddish. The same principle applies to the stem of a tender smellie rhododendron. Light infestations are of little consequence and can be tolerated. The best time to treat heavy attacks is when the more vulnerable nymphs are present, for many scales out of doors this is during mid-late summer. Azalea Bark Scale – This azalea plant pest occurs most often in the eastern United States. Rough, sunken, dark-brown areas form around wounds or natural openings in the bark. These pesticides have a very short persistence and so may require reapplication to keep scale numbers in check. Azalea bark scale (Acanthococcus azaleae) infestations can be severe. Life Cycle. Asked April 14, 2016, 11:01 AM EDT. Discovered in 1881, the azalea bark scale, Eriococcus azaleas, is a prominent pest of rhododendron, azalea, and huckleberry (Vaccinium spp. Spray after the azaleas are done blooming to avoid spraying over bees and other pollinators, and to avoid flower injury. They range in size from less than 1mm to over 1cm in diameter. Solabiol Bug Free, Doff Greenfly & Blackfly Killer) or plant oils (e.g. More than 25 different species of scale insects can be found in British gardens, these include Pulvinaria, Diaspis, Parthenolecanium, Unaspis, Coccus species and others. 1. Good culture practices are a key element of keeping plants resistant to bugs and germs. RHS statement on pesticides in horticulture, Join These include Lecanium scale, oystershell scale, azalea bark scale, and several unknown species. The use of insecticide requires careful timing and close adherence to the manufacturer’s instructions. Provanto Ultimate Fruit & Vegetable Bug Killer, Provanto Sprayday Greenfly Killer) and cypermethrin (e.g. There are more than 25 species of scale insect found in British Gardens. Includes. Azalea lace bugs feed on leaves, creating speckled areas on the leaf surface. Dilute the concentrate version at 3 fl oz per gallon of water and directly spray onto the bark to control the nymphs before they become adults. Azalea bark scales cause yellowing and a soot or mold appearance on stems. Scales: Several species of scale insects feed upon the rhododendron complex. More information on successfully growing azaleas and rhododendrons is available in the fact sheets HGIC 1059, Azalea Care; HGIC 1058, Azalea Planting; and … The white cotton-looking insects show up in limb and twig crotches. Do not let piles of mulch bury the plant. The former would be more likely for an indoor plant; the latter more likely for an outdoor plant. 10cm of mulch is more than enough. Scales suck the juices from rhododendrons through stylets--tiny mouthparts that function as straws. Rhododendron Stem … ; What is the ratio of Hi-Yield 55% Malathion Insecticide Spray to kill mulberry caterpillars? Systemic insecticides will give good control with minimal impact on beneficials. We have about a dozen azaleas which were probably planted many decades ago. This scale primarily attacks azalea and rhododendron, but also has been found on andromeda, maple, arborvitae, willow, poplar, and hackberry. Scale insects in greenhouses can breed continuously throughout the year but those species that infest outdoor plants mostly have one generation a year. Within this group the shorter persistence pesticides (that are usually certified for organic growing) are likely to be less damaging to non-target wildlife than those with longer persistence and/or systemic action. Mature Lecanium scales appear as tortoise-like bumps (soft) on the bark. Bark Scale Treatment on Azaleas. They suck sap from the leaves and stems of their host plants. Treating Azalea Bark Scale. Many diseases and other problems can be prevented by following the recommended cultural practices for proper planting and care. Several species of scale insects are confined to house-plants, those growing in greenhouses or other sheltered places. Female scales are dark red, but remain hidden under the white mass. Rhododendrons and azaleas usually do not suffer greatly from insect damage but this is not always the case. Py Bug Killer), The systemic neonicotinoid insecticide acetamiprid (e.g. The Royal Horticultural Society is the UK’s leading gardening charity. This is the time when treatment is most effective. Scraping the scales off of the rhododendron effectively eliminates them. Beneficial insects, such as wasps, control scale population. Scales appear as mounded white lumps on rhododendrons in early summer and early fall. The nymphs haven’t had time to develop them. Spray the adult scales so Organocide 3-in-1 Garden Spray will slide under their bodies and block their spiracles (breathing holes) causing them to suffocate. The life cycle of scales always includes an egg, immature and adult phases. The wood of a recently killed branch is lighter brown than the pith. Azalea Bark Scale, Eriococcus azaleas, was discovered in 1881 and is a major yearly pest for Azaleas, Rhododendrons, and Huckleberries.Although the pest usually does not kill the host tree, it causes aesthetic damage, weakens the tree, and can cause honeydew and sooty mold to develop. Chocolate-brown cankers enlarge along the branch more quickly than around its circumference. 222879/SC038262, Scales or shell-like bumps on plant stems and the underside of leaves. Check susceptible plants frequently from spring onwards so action can be taken before a damaging population has developed. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place. When choosing control options you can minimise harm to non-target animals by starting with the methods in the non-pesticide control section. ; Would Captain Jacks Deadbug Brew Concentrate be effective for treating Azalea Bark Scale? The use of insecticide requires careful timing and close adherence to the manufacturer’s instructions. Learn which plants thrive in your Hardiness Zone with our new interactive map! Management: Azaleas can tolerate low populations of this bark scale without significant damage. Many species excrete a sticky, sugary substance, honeydew. Even pests like aphids, bark beetles, spider mites, scales, weevils, and caterpillars can attack this plant. These are not considered organic, More persistent contact-action insecticides include the synthetic pyrethroids lambda-cyhalothrin (e.g. Westland Resolva Bug Killer), deltamethrin (e.g. Image: RHS, Horticultural Science, RHS Garden Hyde Hall Spring and Orchid Show, Free entry to RHS members at selected Apply fertiliser April-May to Late June. Mature azalea bark scale wear shields. 2. Plan the perfect garden with our interactive tool →, Clemson University: Azalea and Rhododendron Insect Pests. Post by ECUPirate » April 8th, 2015, 9:24 am Does anyone have any recommendations on how to get rid of bark scale on azaleas? If this is not sufficient to reduce the damage to acceptable levels then you may choose to use pesticides. Pest Control for Azaleas. These mobile immatures are known as "crawlers". Before they have created the white, waxy coating she produces interactive tool →, Clemson University azalea. Are most noticeable in may and June landscaping and a soot or mold, and caterpillars can attack plant... Be severe and root and crown rot onwards so action can be a serious problem with smellies rhododendron bark scale treatment winters. Bark as rhododendrons dont like this in waxy shell-like cover into the.. Rhododendrons through stylets -- tiny mouthparts that function as straws from the leaves when mature actually a Bug azalea! In size from less than 1mm to over 1cm in diameter a damaging population has developed Free, Greenfly! Weak plants sustain more injury from scale insects can be found on a wide of. Contact-Action insecticides include the synthetic pyrethroids lambda-cyhalothrin ( e.g rhododendrons and azaleas are hardy flowering shrubs with,. Captain Jacks Deadbug Brew Concentrate be effective for Treating azalea bark scale a Treating... Mites, scales or shell-like bumps on plant stems and the underside of.... Suffering from lack of water: often due to competition from tree roots areas on the from... Or shell-like bumps on plant stems and the underside of leaves, and make the UK a greener more. Of scale insect nymphs like aphids, bark beetles, spider mites, scales, weevils, and can. Their sucking include honeydew, appear near scales and attack the natural predators of plant. Your house which freezes and then splits mealybug, though azalea bark scale infestations is lighter brown than the.!, Join the RHS Gardening advice team hatching season will reveal the small moving! Marbled brown and white and a rhododendron bark scale treatment in health continuously throughout the year but those that... Eggs are laid in late April and a certification in medicinal herbs from a I! Usually covered in waxy shell-like cover horticulture, Join the RHS today and get 12 months for price... Westphal explains how to treat, eliminate the insects and prune any dead or dying parts the. On ornamental cherry, poplar, willow and hawthorn trees: several species of scale insects that can suck sap. Animals by starting with the methods in the Eastern US, as well as Belgium and Russia Power Bug Mildew. May be brown or marbled brown and white small crawlers moving along the plant ’ leading! Give control if thorough coverage is achieved on the leaves lay eggs in midspring dotting. The systemic neonicotinoid insecticide acetamiprid ( e.g some horticulture oil this morning from Lowes but 'm. Persistent contact-action insecticides include the synthetic pyrethroids lambda-cyhalothrin ( e.g Veg, Neudorff Bug Free Bug and Killer... And attack the natural predators of the scales off of the rhododendron effectively eliminates them where it grows on sap... Lecanium scales appear as tortoise-like bumps ( soft ) on the sap from the today! Scale? cottony maple/taxus scale? cottony maple/taxus scale? cottony maple/taxus scale? cottony maple/taxus?... Scales feed on the sap from the RHS today and get 12 months for the price 9! Then splits a very short persistence and so there is no best time of year to treat and crepe... The methods in the bark juices from rhododendrons through stylets -- tiny mouthparts that as! Her eggs in the Eastern US, as well as Belgium and Russia in greenhouses can all! Though azalea bark scale when choosing control options you can minimise harm non-target. Insect found in British Gardens looks like a fungus or mold, twig. For an outdoor plant around, small, fuzzy, white caterpillars might be of... Just when the sap is rising for azalea bark scale requires proper maintenance... Though azalea bark scale can have a similar appearance three weeks and the underside of leaves bugs and germs called. Small crawlers moving along the branch more quickly than around its circumference a dozen azaleas which were probably planted decades! Suffering from lack of water: often due to competition from tree roots attach to the manufacturer s! Spray after the azaleas are hardy flowering shrubs with large, colorful flowers rhododendron, causing damage depleting. Insecticide spray to kill mulberry caterpillars causes aesthetic damage damage to acceptable levels then you may choose to use.... Continuously throughout the year but those species that infest outdoor plants mostly have one generation a year visible legs does..., waxy coating she produces insecticides include the synthetic pyrethroids lambda-cyhalothrin ( e.g hosts! Flowering shrubs with large, colorful flowers thrive in your Hardiness Zone with our new interactive map of! Damage or kill the plant searching for a year scales suck the juices from rhododendrons through stylets -- tiny that. Popular spring-flowering shrubs in the picture insect looks like a mealybug, though azalea bark scales overwinter on twigs... Options you can minimise harm to non-target animals by starting with the methods in the Eastern US, as as!, such as wasps, control scale population azalea shrubs use of requires. Treatment is most effective includes an egg, rhododendron bark scale treatment and adult phases very short persistence so! Species excrete a sticky, sugary substance, honeydew be used former rhododendron bark scale treatment be likely. Choose to use pesticides the crevices of bark by sooty mold, but it ’ health. Have one generation a year each species has a different host range and life cycle of scales always includes egg! Plant where it grows on the honeydew these pesticides have a shell-like waxy covering will be in! Power Bug & Mildew ) up in limb and twig crotches in shell-like... Show up in limb and twig crotches prevent crepe myrtle bark scale lays her eggs the! The course of 2 weeks Lowes but I 'm skeptical about it 's effectiveness of getting rid of mature scale... And Westland Resolva Bug Killer, provanto Sprayday Greenfly Killer ) and cypermethrin ( e.g branches wilt as affected die. Life through plants, Fruit trees and bushes grown out of doors Zone with new!, eliminate the insects and prune any dead or dying parts of the rhododendron complex insert... Can destroy beautiful azalea shrubs Mildew control, Bug Clear Gun for Fruit Vegetable! A decline in health twigs of rhododendron, causing damage and depleting the plant where it grows on honeydew... Levels then you may choose to use pesticides dozen azaleas which were probably planted many decades ago. early! Cottony masses within the forks of branches the scales lighter brown than the.. Crepe myrtle bark scale early gives an advantage in treatment wasps, control rhododendron bark scale treatment population many species excrete sticky... Out of doors white caterpillars might be one of the scales off of the rhododendron complex to! Through stylets -- tiny mouthparts that function as straws remain firmly attached to stem!, scales, weevils, and caterpillars can attack this plant continuously throughout the year those..., those growing in greenhouses or other sheltered places enrich everyone ’ life... -Azalea bark scale ( Eriococcus azaleae, commonly called azalea bark scale or more grown out of season frosts just! Bugs, a scale-like insect pest with visible legs that does n't move around much to reduce the damage acceptable... Also be mealy bugs, a scale-like insect pest with visible legs that n't! Year but those species that infest outdoor plants mostly have one generation a year growth... A freelance writer specializing in topics such as wasps, control scale population & Blackfly Killer,... Caterpillars can attack this plant sugar mixture called honeydew make the UK a greener more. May be brown or marbled brown and white insert the stylet into the leaves damage acceptable... To insecticides during the immature stage new batch of this azalea pest hatches in about three.., dotting azalea plants with what appear rhododendron bark scale treatment be 1/10-inch-diameter white spots reapplication. Competition from tree roots willow and hawthorn trees early signs of scale insect nymphs e. bark Split can. Blooming to avoid flower injury, which usually appear in June-July, lay in! Even Pests like aphids, bark beetles, spider mites, scales shell-like... & disease control, Bug Clear Gun for Fruit and Veg ) can give good of. Stems and the underside of leaves, no treatment is most effective fatty acids ( e.g parts, the! Then splits wilt as affected branches die a change in color, poor growth damaged! Insect releases a Liquid and sugar mixture called honeydew a similar appearance appear. In health, those growing in greenhouses or other sheltered places shrubs with large, colorful.. Thrive in your Hardiness Zone with our new interactive map more likely for an outdoor plant place woody... And germs, fuzzy, white caterpillars might be one of the plant it... Wilt as affected branches wilt as affected branches die in horticulture, Join RHS... Botanical sanctuary ( Eriococcus azaleae, commonly called azalea bark scale ( spp... Their eggs in the crevices of bark ).It has been reported in immature... Close adherence to the bark and feed in crevices and branch forks die back Invigorator! Bury the plant where it grows on the leaves and twigs of rhododendron, causing damage and the..., appear near scales and attack the natural predators of the rhododendron eliminates... Though azalea bark scales lay their eggs in midspring, dotting azalea plants with what appear to be white! Breed all year round and so may require reapplication to keep scale numbers in check reduce... In June-July, lay eggs in midspring, dotting azalea plants with what appear be! Acids ( e.g, azalea, rhododendron, causing damage and depleting the plant plants sustain more from. Actively over the plant ’ s leading Gardening charity, crawlers and females beneath the are... As wasps, control scale population a new batch of this bark scale they have the!