Ants, wasps and other insects may be attracted to the sweet honeydew. Phil Pellitteri, UW Insect Diagnostic Lab, UW-Extension Revised:  8/6/2012 Item number:  XHT1153. Light, paraffinic oil, such as Year-Round spray oil and All Seasons spray oil, however, can be used during the summer. Photo by Dan Gill/LSU AgCenter, Tea scale. When they first hatch out of their eggs, scale insects are mobile. Once the crawlers have settled down to feed, they create their protective covering and contact insecticides are largely ineffective. As scale insects feed on the sugary sap of a plant, they excrete some of the sugar as a liquid called honeydew. Euonymus scale is a non-native scale that attacks evergreen shrub and vine forms of Euonymus (e.g., wintercreeper). Eggs are protected under female scales and hatch in early June. Oils are also effective against aphids, whiteflies, spider mites and the crawler stage of scales, yet they are less harmful than other insecticides to beneficial predatory insects. When the scale insects feed on the sap, they ingest the toxic insecticide and are killed. The lady beetle Cybocephalus nipponicus can be purchased by homeowners and released to aid in control. These insecticides are sprayed onto the plant or applied to its roots. Treatment involves pouring the mixed insecticide at the base of the plant. And sooty mold does not occur with some scales, such as tea scale. Imidacloprid-containing insecticides are used as soil drenches and should be applied in the fall. Control: Euonymus scale can be difficult to control. Feedback, questions or accessibility issues: © 2020 The Board of Regents of the University of Wisconsin System. Many gardeners don’t recognize there is a problem until the plant is heavily infested and damage has occurred. Thorough coverage of both the upper and lower leaf surfaces is required for spray insecticides to be effective. When the scale feed on the sap, they ingest the toxic insecticide and are killed. Acephate, imidacloprid and dinotefuran are three commonly used systemic insecticides that are effective against scale. Treatment involves pouring the mixed insecticide at the base of the plant. Systemic insecticides provide an option for control when temperatures limit the use of an oil spray or when drenching around the base of the plant is more practical. Scale insects are one of the more common groups of insects that attack plants. Oil sprays help speed the process. However, while these products reduce scale populations, they typically do not provide 100% control of Euonymus scale on woody plants. However, it may need to be applied several weeks before crawlers are active for best results. Florida wax scales look like waxy, white domes about the size of a nail head and occur on a wide variety of plants. This provides a means of scale control without reliance on sprays. Many scales produce crawlers in the spring. You may find them feeding on trees, shrubs and even on indoor plants. The insects are suffocated rather than being killed by a toxic material. 225-578-4161 If the insects are on the underside of the leaves and the oil is only applied to the upper surface, it will have no effect on them. Always read and follow label directions carefully when using any pesticide. These fungi feed on the honeydew and do not attack or directly damage the plant, but the appearance of sooty mold is often the gardener’s first noticeable sign of trouble. Both suck on plant tissue, which can cause damage. At this stage, they are called crawlers, and they are very tiny. AgCenter, The LSU AgCenter and the LSU College of Agriculture, 101 Efferson Hall Soft brown scale occurs on ficus, scheffleras and other indoor plants. Systemic Insect Control will effectively kill the crawler stage, which is the immature scale, but is … Adults are protected from these insecticides by their scale coverings, and only young crawlers can be killed with spray treatments. Acephate, imidacloprid and dinotefuran are three commonly used systemic insecticides that are effective against scale. Brand names of spray oils include Volck (use only during cool weather), All Seasons and Year-Round. Fern scale appears as white dashes on the fronds. Finally, two parasitic wasps and two predatory beetles have been introduced into the US to help control Euonymus scale. Because scale insects are difficult to kill, one or two follow-up applications should be made after the first one. Be aware that other sucking insects, such as whitefly and aphids, also produce honeydew that can lead to sooty mold. Systemic insecticides for use on landscape plants include neonicotinoids (acetamiprid, dinotefuran, imidacloprid, and thiamethoxam) and the organophosphate acephate (Lilly Miller Ready-to-Use Systemic, Orthene). Crawlers can be controlled with contact insecticides such as insecticidal soap or malathion, but most gardeners never notice them and miss the opportunity. Nymphs are active over a period of a few weeks, and develop into adults after four to five weeks. When infestations are heavy, scales encrust leaves and branches, with feeding damage causing defoliation and branch dieback. Symptoms and Effects: Euonymus scales feed on plant sap. The safest effective way to control scale is with a horticultural oil spray. We teach, learn, lead and serve, connecting people with the University of Wisconsin, and engaging with them in transforming lives and communities. Acephate (various brands) and imidacloprid (Bayer Advanced Tree and Shrub Insect Control and other brands… When mixed and sprayed onto an infested plant, the oil coats the scale insects and clogs their breathing pores. Systemic insecticides provide an option for control when temperatures limit the use of an oil spray or when drenching around the base of the plant is more practical. Spray insecticides containing carbaryl, cyfluthrin, horticultural oil, insecticidal soap, malathion, or permethrin can be used for control of the crawler stage of Euonymus scale. Systemic insecticides such as imidacloprid can also be used for control. 225-578-4143 This water soluble insecticide is taken up by the roots and transported throughout the plant where it is ingested by sap feeding insects. Scales also cover themselves with waxy material that protects and hides them. Euonymus scale males are smaller than females, white and elongated. That’s one reason that the mild weather of spring is an excellent time to use them. Once they settle down to feed and pierce the plant’s tissue with their needle-like mouthparts, they never move again and become firmly attached to a leaf or stem. The immature stages of the insect are called nymphs and an early mobile nymph stage is called the crawler stage. This second generation matures, and the adults overwinter. Tea scale insects are about the size of a hyphen, appear slightly fuzzy and are white or brown.