Young scales are yellow to orange crawlers and are found on the leaves and twigs of trees. Crawlers migrate from leaves to branches where they feed and overwinter. Wrap the trunk with a collar of fabric tree wrap, heavy paper, or masking tape to avoid injury to bark; wedge pliable wrap snugly into cracks and crevices; and coat the wrap with the sticky material. The most commonly found soft scales are Coccus hesperidum - the adults are 3-5mm long, green to brown in colour, oval- shaped and appear slightly flattened, and Saisettia coffeae - the adults are 5mm or longer in length, deep brown in colour and dome-shaped. Scales in the family Diaspididae are called “armored scales” and their scale covering can be removed because it is usually free from their bodies. If ants are abundant, selectively control them. Dreistadt, S. H. 2010. Nondiscrimination Statement. Eggs are produced within the female and hatch into first stage nymphs, or crawlers, when they are laid. Especially common is the brown soft scale (Coccus hesperidium) shown above, and possibly the similar elongate soft scale (Coccus longulus). It is important to correctly distinguish the scale family (e.g., armored versus soft scale) and often the particular species of scale to determine whether control is warranted; and if so, what methods and timing of control action are effective. To control most scales overwintering on deciduous woody plants, thoroughly spray the bark of terminal shoots with oil during winter. Boisduval’s scale (Diaspis boisduvali), also called Boisduval scale, , , , the scurge of the southern orchidists, is rarely encountered in northern home collections and apparently does not survive well here, except in the larger collections. The Scale Insects of California Part 2: The Minor Families. You can prune off heavily infested twigs and branches, if they are limited to a few parts of small plants. Double over the loose end of the tape several times to make it easier to remove. Both hard and soft scale females ultimately die, and their bodies form a protective covering over the eggs and for emerging crawlers. As a result, heavily infested plants become unsightly and often loose their leaves. Natural enemies are commercially available for release against California red scale and perhaps certain other scales. Res. Except for crawlers and adult males, armored scales lack obvious appendages and spend their entire life feeding at the same spot. Life Cycle: Intermediate. They are 1.5 to 2.5 millimeters long. Pest Notes: Black Scale. Description: Adults are oval, flattened, slightly convex, reddish-brown scale insects. For oak pit scales, sycamore scale, and other harder to control species, spray during the plant’s delayed-dormant period, which is after the buds swell but before buds open. Most soft scales have one generation each year and overwinter as second instar nymphs. The presence of scales can be easily overlooked, in part because they do not resemble most other insects. Description. In comparison with systemics that are sprayed onto foliage, products labeled for soil drench or injection, or for trunk injection or spray minimize environmental contamination and may be more effective than contact insecticides. Soft scales, family Coccidae, grow up to 1⁄4 inch long and have a smooth, cottony, or waxy surface. Rose M, Stauffer S, 1997. Depending on the scale species and the extent to which biological control has been disrupted, it will take several months of conservation efforts (such as controlling ants and dust and avoiding application of persistent insecticides) or until the next season or longer before scale populations are reduced by biological control. Soft scale (family Coccidae) Soft scales are probably the most commonly encountered species of scale insect in production nurseries (refer to Table 1). See Pest Notes: Ants for more information. Nat Res. If a large proportion of scales are dead or parasitized by natural enemies, consider delaying a treatment decision and monitor the population again later before deciding whether to apply pesticide. 1988. Avoid creating dust because it interferes with natural enemies. There are more than 25 species of scale insect found in British Gardens. Boisduval scale is the most common type of scale found on orchids and can multiply rapidly. Res. Ant control, habitat manipulation, and pesticide management are the key natural enemy conservation strategies. Oriental scale Passionvine bug Pink wax scale Potato moth Queensland fruit fly Red scale Red-shouldered leaf beetle Root-knot nematode Silverleaf whitefly Soft brown scale Stem girdlers Sugarcane bud moth Swarming leaf beetles Tomato russet mite Two-spotted mite A well-timed and thorough spray of horticultural (narrow-range) oil during the dormant season, or soon after scale crawlers are active in late winter to early summer, can provide good control of most species of scale. Adult female scales and immatures (nymphs) of most species are circular to oval, wingless, and lack a separate head or other easily recognizable body parts. Description. Eventually twigs and entire limbs die and the tree bark cracks and oozes sap. The Regents of the University of California. A hand lens is usually needed to detect the crawlers. Food Agric. (PDF) 4(1) March 2014. Products include bright yellow cards that produce distinct blue dots upon contact with honeydew or water. 3386. Pest Notes: Oak Pit Scales. Natural Enemies Handbook: The Illustrated Guide to Biological Pest Control. Pests of Landscape Trees and Shrubs: An Integrated Pest Management Guide. Life Cycle. Oakland: Univ. Do not mix oil with chlorothalonil, sulfur, and certain other fungicides; and do not apply oil within 3 weeks of an application of sulfur-containing compounds, such as wettable sulfur. This scale gives birth to pale yellow crawlers. Contact webmaster. PDF: To display a PDF document, you may need to use a Each species has a different host range and life cycle. Crawlers walk over the plant surface, are moved to other plants by wind, or are inadvertently transported by people or birds. 7470. Res. Certain scale problems on large plants and hosts especially sensitive to scale damage may warrant the application of a systemic insecticide. Gardens, Landscapes, and Turf > Coccus viridis is a soft scale insect in the family Coccidae with a wide host range. Crawlers can be moved around by wind, by ants, or by hitching a ride on a bird's leg. Late spring and summer are also the times to spray avocado, citrus, and many other broadleaf evergreens. Scale look like small bumps and can be mistaken for part of the plant, as adults do not move. The brown adult females dies and remains at one end of the ovisac. Publ. UC Statewide IPM Program. Monitor and record scale densities and use the density that caused damage (dieback or unacceptable honeydew) as your preliminary control action threshold. The Scale Insects of California Part 3: The Armored Scales. Pest Notes: Cottony Cushion Scale. The surface has a hatched appearance. 2012. Oakland: Univ. Division of Agriculture and Natural Resources Pest Notes: Sycamore Scale. After about a week, they molt into the second stage, passive nymph. With external parasites that feed outside the scale body, but under the cover of armored scales, their maggotlike larvae may be observed by prying off the scale cover. Description of adult: The species that occurs on lychees and longans has a raised oval brown covering 3-5 mm in length. Periodically stir sticky material with a stick to prevent ants from crossing on collected debris. Unfortunately, we cannot provide individual solutions to specific pest problems. Scientific Name: Coccus hesperidum Linnaeus, Lecanium sp. Nat. Systemic insecticides are absorbed by one plant part (e.g., trunks or roots) and moved (translocated) to leaves and other plant parts. Grafton-Cardwell, E. E. 2012. For noncommercial purposes only, any Web site may link directly to this page. There is a longer time delay between soil application and insecticide action. Calif. Agric. Hard scale females continue to molt and later lose their legs and cannot move (remaining sessile for the rest of their life). Armored scales do not produce honeydew. To obtain adequate control, thoroughly wet the infested plant parts with spray, typically shoot terminals and the underside of leaves. 3332. Scales. Oakland: Univ. For example, rinse small plants when foliage becomes dusty. It retains its legs and antennae throughout its life. Symptoms. Honeydew drippings from plants can be efficiently monitored using water-sensitive paper, which is commonly used for monitoring insecticide droplets and calibrating sprayers. Authors: J. N. Kabashima, UC Cooperative Extension, Orange and Los Angeles Counties; and S. H. Dreistadt, UC Statewide IPM Program, Davis. If the scale produces honeydew, this sticky excrement, sooty mold, and the ants attracted to honeydew can annoy people even when scales are not harming the plant. Provide plants with good growing conditions and proper cultural care, especially appropriate irrigation, so they are more resistant to scale damage. Homes, Scale insects are sap-feeding insects named for the scale or shell-like waxy covering that conceals their bodies. Various other organisms resemble scales but have different biology and management. Some scale species, when abundant, weaken a plant and cause it to grow slowly. More than one application per growing season may be needed, especially if the targeted pest has more than one generation a year. The adults reach up to 4mm long, the immature (nymph) stages are much smaller. They feed by sucking sap and some can weaken host plants, many excrete a sticky substance (honeydew), which allows the growth of sooty moulds. They tend to be gray/brown/black. are common soft scales on a wide range of woody ornamental plants and fruit trees. Where plants can be sprayed, complete spray coverage of infested plant parts with horticultural oil at the proper time provides good control of most scales. Predatory lady beetle (ladybug) species of Chilocorus, Hyperaspis, and Rhyzobius, can easily be overlooked because the adults of many species are tiny or colored and shaped like scales, and their larvae may feed hidden beneath scales. Common scales and their tree and shrub hosts are listed in Tables 1–3. Res. Some of these products are for licensed professional applicators only. 7409. Sprays only kill foraging workers, while ant baits are carried back to the nests where reproductive queens and the entire colony underground can be killed. Oakland: Univ. The soft brown scale attacks a wide variety of field, orna-mental and greenhouse plants worldwide (Zimmerman, 1948). Do not apply systemic insecticides to plants during flowering or shortly before flowering; wait until after plants have completed their seasonal flowering unless the product’s label directions say otherwise. Exceptions are when natural enemies are disrupted by ants, dust, or the application of persistent broad-spectrum insecticides. Scientific name: Coccidae. Diamond “scale,” which infests palms, is actually the fruiting bodies of a blackish fungus (Phaeochoropsis neowashingtoniae). 7411. Accessibility   Scale insects can weaken and even kill trees, shrubs and houseplants, but in general, complete loss of the plant is rare. A fungus called sooty mold colonizes the honeydew and causes the surface to turn black. Brown soft scale is flat and oval during larval and adult stages with color ranging from yellowish to light brown. Their surface is the actual body wall of the insect and cannot be removed; flipping the cover removes the insect body and cover together. Color becomes darker as the scale ages, and its outer covering becomes tougher. Flint, M. L., and S. H. Dreistadt. Nat. Nat. Lecanium scales (Lecanium sp.) Common scales include black scale, pink wax scale, cottonycushion scale, San Jose scale, soft brown scale, red scale and white louse scale. Tape traps for crawlers and honeydew monitoring are useful in certain situations for determining the need and best timing for pesticide application. Res. Shady new leaf and stem growth is preferred as sites for infestation. The most serious problem they cause is honeydew which is a clear, sticky secretion they leave behind as they feed. Although baits require users to be patient, they can be much more effective than sprays. The male armor is white felted, three-ridged, and the crawler cast skin is beige to yellowish brown. Scales are sucking insects that insert their tiny, strawlike mouthparts into bark, fruit, or leaves, mostly on trees and shrubs and other perennial plants. Dinotefuran (Green Light Tree and Shrub Insect Control with Safari 2G, Safari) controls most types of scales. Armored scales and soft scales are the most common types (or families). Brown soft scale, Coccus hesperidum Linnaeus (Homoptera: Coccidae), on satsuma. Inspect wraps at least several times a year for damage to bark and remove and relocate any wrap at least once a year to minimize bark injury. Photo by Drees. Males are uncommon. The wax covers the insects which feed on the sap. Change the tapes at weekly intervals. If a spring or summer foliar insecticide application is planned, unless another time is recommended for that species, spray after crawler production (abundance in traps) has peaked and definitely begun to decline, which is soon after most crawlers have settled. Transparent double-sided sticky tape can be used to effectively time a foliar insecticide application. Many species are usually well controlled by beneficial predators and parasites (natural enemies). Winged adult males and females emerge in about a month. Trunk application of an effective systemic insecticide can provide relatively rapid control. The adult female scale insect is oval and dome-shaped, about 3 to 5 mm (0.12 to 0.20 in) long. Horticultural oil is effective in spring or summer on deciduous plants when sprayed soon after most crawlers have emerged and most scales are in the young nymph stage. The first symptoms are yellow, falling leaves. To deny ants access to plant canopies, prune branches or weeds that provide a bridge between buildings or the ground and apply a sticky material (Tanglefoot) to trunks. Effective, slow-acting bait insecticides work over a period of days so that before ants die they will spread the toxicant among many other ants during food sharing. Eggs hatch into tiny crawlers (mobile first instar nymphs), which are yellow to orangish in most species. Regularly monitoring honeydew beneath plants, such as the number of drops during four hours on the same time of day once a week, can help to develop thresholds and evaluate effectiveness of the treatment. Res. The adult scale lays up to 1000 eggs that hatch into crawlers. Oakland: Univ. Some scales change greatly in appearance as they grow, and some species have males and females that differ in shape, size, and color. Publ. Nymphs of some species can move slowly, such as soft scales that feed on deciduous hosts and move from foliage to bark in the fall before leaves drop. PDF reader. The size, shape and characteristics of the female also vary with different host plants. Do not apply oil or other insecticides when it is foggy, freezing (under 32°F), hot (over 90°F), when relative humidity is above 90%, or if rain is expected in the next 24 hours. Check a portion of the scales to be certain they are alive and to evaluate the extent of parasitism as described above. 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