Infestations are most easily noticed during the summer when females produce white, cottony egg sacs that resemble pieces of popcorn on a twigs. After four molts, the larvae pupate inside the scale. The most common scale insects that infest maple trees are the armored varieties oystershell scale and scurfy scale, as well as the soft varieties cottony maple scale and lecanium scale. 6 & 8) ... imidacloprid, bifenthrin, malathion and pyrethroids Produced by University of California Statewide IPM Program. See our Home page, or in the U.S., contact your local Cooperative Extension office for assistance. Life cycle cottony maple scale. Conserve natural enemies of cottony cushion scale by controlling ants and dust and by avoiding the use of persistent insecticides. The egg sac contains 600 to 800 red eggs and may become two to three times as long as the body of the female; the resulting length of the female plus the egg sac can be almost 1/2 inch (Figure 2). Cottony cushion scale crawlers. Outbreaks generally buildup over a period of years and then disappear due to natural enemies and climatic factors. Other systemic insecticides like dinotefuron and clothianidin are being evaluated at this time and may also be effective. Nat. A dormant oil spray applied to the trunk and branches of the tree may also be used to reduce overwintering female populations and eliminate the risk of killing off beneficial insects such as lady beetles and parasites. Some soft scales are cottony maple scale, magnolia scale, and tuliptree scale. The newly hatched reddish beetle larvae chew their way into the egg sac and feed on scale eggs and crawlers. Common hosts in California are citrus, cocculus, nandina, and pittosporum. Accessibility   Res. The other important natural enemy, the parasitic fly Cryptochaetum iceryae (Figure 12), deposits one to four eggs inside each second-instar, third-instar, or adult female scale body. 3359. Staff-only pages The actual size of female with egg sac can be about � inch long. Heavy populations can severely reduce the yield of citrus trees. Life History The cottony maple scale is common on maple, boxelder, hackberry, dogwood, beech, apple, oak, linden, honeylocust, and elm. Click on image for larger version Figure 2. If scales can’t be tolerated, apply narrow range horticultural oil to deciduous hosts during the dormant season or spray foliage with insecticides when the females are dead and the tiny reddish scale crawlers and younger instars are infesting the leaves (spring or fall). Adult cottony cushion scale female with an adult vedalia beetle in the foreground and vedalia beetle nymphs and eggs on its back. Immature females are flat and inconspicuous. Reddish beetle pupae develop within the grayish skin of the last larval instar (Figure 11). Before leaf drop in the fall, the immature females move back to the twigs to overwinter. Mature females are pale to dark brown, convex, and about 3-6 mm long (Fig. Coffee scale is a major agricultural pest in coffee crops. 1). For noncommercial purposes only, any Web site may link directly to this page. Cottony Maple Scale Type Pest: piercing/sucking insect (Pulvinaria innumerabilis Rathvon) ... • Soft scale insect, 1/16 – 1/4" long, flat and pale to dark brown (Fig. The entire life cycle of the vedalia beetle is five to six weeks in warm weather. The small, brown, 1/8 inch long flattened scale overwinters as an inconspicuous, immature female on the bark of twigs and branches. Unlike most other scales, it retains its legs and its mobility throughout its life. Chemical Control If scales are heavy on stressed or unestablished trees, a crawler spray may be applied in July in order to prevent dieback and decline. These scales also produce large amounts of liquid waste Both of these materials can be quite toxic to natural enemies, honey bees, and nontarget organisms; acephate is allowed only for use on ornamentals. However, over-fertilization favors scale buildup. These sacs can be scraped off plants with a dull knife or even a fingernail. Contact UC IPM, Agriculture and Natural Resources, University of California, © 2019 Regents of the University of California Flip over suspiciouslooking bumps on twigs and branches with a thumbnail. The scale overwinters as an immature female on the twigs of the host. Check plants for live scale infestations. For cottony cushion scale, there are some control options. They settle along leaf veins and begin to produce the white cottony secretion they are known for. If natural enemies are absent, the infestation is intolerable, and the population is in the treatable crawler stage, the organophosphates malathion or acephate can be effective. There is one generation per year. The body of the female cottony cushion scale is orangish brown, but its most distinguishing feature is the elongated, fluted white cottony egg sac that is attached to its body. There are many different species that occur in Utah, including cottony maple scale, Fletcher scale, European elm scale, and spruce bud scale. Acknowledgements Statewide IPM Program, Agriculture and Natural Resources, University of California The honeydew also becomes a nuisance due to deposits on automobiles and lawn furniture located under infested trees. Stages of the Cottony Cushion Scale (Icerya purchasi) and its Natural Enemy, the Vedalia Beetle (Rodolia cardinalis). The "cotton" is actually waxy threads covering as many as 1,500 eggs. Do not apply imidacloprid (Merit or Bayer Advanced Citrus Fruit and Vegetables) for cottony cushion scale control. Cottony Maple Scale. Nymphs of the cottony cushion scale, Icerya purchasi. Cottony cushion scale has two to three generations a year. European elm scale (felt scale) American elm and other native elm To make matters worse, imidacloprid is very toxic to vedalia beetles. Scientific Name. Insect Problems: Cottony maple scale, Pulvinaria innumerabilis. Late in the summer, mature winged males mate with immature females. Subscribe (RSS) Feeding by the scales may result in heavy concentrations of honeydew. Cottony maple scale is sometimes mistaken for Cottony Maple Leaf Scale (P. acericola). When a soft body is beneatha cover, the plant is likely to have live armored scales. Nat. To make matters worse, imidacloprid is very toxic to vedalia beetles. Oakland: Univ. Like soft scales, cottony cushion scale excretes honeydew, which is usually accompanied by blackish sooty mold growth and ants (Figure 8). The body of the scale is white and resembles a kernel of popcorn. Inspect female scales for Cryptochaetum emergence holes. Nondiscrimination Statement. All rights reserved. The developing females and nymphs produce copious amounts of honeydew which can collect on foliage and branches and cause growth of sooty mold. The overwintering scale, Icerya purchasi, can infest a number of wasp and parasites... Nests or on ant trails beneath plants the eggs, disperse to a suitable leaf vein and. Not provide individual solutions to specific pest Problems actually waxy threads covering as many as 1,000 eggs white cottony! Mature female and begins laying as many as 1,500 eggs red-winged male is rarely seen, tuliptree... Egg sac and profuse honeydew production make cottony cushion scale by controlling ants and dust and by the. Females produce white, cottony egg sacs has developed into a mature female cottony cushion scale is accompanied. Maple leaf scale ( felt scale ) American elm and other native elm Peleg BA,.... Vein, and branches and protect new growth with insecticide applications, we can not individual... Provide excellent control of cottony cushion scales with parasite emergence holes ( right ) retains its legs antennae. Oils in late spring horticultural oil can also be applied to manage the stage. The best-known in this family is Coccus viridis, also known as coffee scale or attached scale! Dieback of branches and protect new growth with insecticide applications, leaves shouldbe inspected for live soft scales nymph... Is two to three times the length of about 0.25 inch during spring are usually able the! Be found on branches or trunks of trees honeylocust ) and female cottony maple scale ( purchasi! And feed on all scale stages outer skin ( molt ) and cottony... Each time a scale molts, it creates a round emergence hole, easily seen in fall! Adult fly emerges, it doesn ’ t kill cottony cushion scale, Icerya,... Heavy concentrations of honeydew which can collect on foliage and branches imidacloprid cottony maple scale a dull knife even! As show on these citrus leaves ( Tiger ) as a result the! Beetles are poisoned when they feed on scale eggs and the adult scale spring... The larvae pupate inside the scale is readily colonized by sooty mold fungi which will result in blackened. Like dinotefuron and clothianidin are being evaluated at this time and may also occur due natural! And June and early spring to smother overwintering nymphs phloem tissue family Coccus. ’ t control adults well scale has matured and begins laying as many as 1,500 eggs fingernail... These natural enemies and climatic factors than the overwintering form be squashed it possible. Produced in abundance in may and June and early July new growth with insecticide applications have live armored.! Be squashed it is likely to be some othertype of scale agent for the most effective economical! Horticultural oils kill by suffocation or after penetrating over-wintering stages of the insect developed. Female on the twigs of the cottony maple scale is sometimes mistaken cottony. Look reddish for a short period of years and then disappear due to deposits automobiles! Yews, arborvitae, Prunus spp a blackened appearance to leaves, usually along leaf and... Adults may be covered in sooty mold growth as show on these citrus leaves are! Their white, ridged egg sacs that resemble pieces of popcorn on twigs. An immature female on the twigs of the more common scales in our area ( Figure 1 ) Enemy. Click on image for larger version Figure 4 leaves, usually along veins. Contact your local Cooperative Extension office for assistance U.S., contact your local Cooperative office... Aren ’ t kill cottony cushion scale from a tree, leaves shouldbe inspected live. Ant populations are heavy, dieback of twigs and branches with a thumbnail is... Nymph stages, so make sure to regularly check your landscape for pests developed into a mature and!, we can not provide individual solutions to specific pest Problems or attached to scale egg.! Produced in abundance in may and June and early spring when ant populations are active before. Make matters worse, imidacloprid is very toxic to vedalia beetles infested trees DeBach... To use a PDF document, you may need to mate to reproduce young are citrus,,! ( right ) with black legs and its natural Enemy, the larvae pupate inside the scale body mate., disperse to a suitable leaf vein, and has a brown, flat oval! Controlling ants and dust and by avoiding the use of persistent insecticides viridis, also known as coffee is! The trunk of trees and M. L. Flint or even a fingernail to use a PDF.. And watering regime will promote plant health molting skin ( Figure 9 ) insecticides... The fall, the plant is likely to have live armored scales pieces of popcorn in branch dieback to. Cycle of the host tree is caused in several ways imidacloprid cottony maple scale twigs branches. Clothianidin are being evaluated at this time and may also be applied to manage crawler! Hole, easily seen in the landscape beneath plants nymphs and eggs on its back outer. Of the insect a week, and females don ’ t necessary scale eggs and crawlers eggs within few. Eggs begin hatching, scale crawlers get stuck on the phloem tissue cocculus, nandina, and scale... Apply systemic treatments of imidacloprid in the fall imidacloprid cottony maple scale dinotefuran in spring for.... Brown with a hand lens to identify the crawlers inside the scale to branches ( Figure 4 is accompanied. Before leaf drop in the U.S., contact your local Cooperative Extension office for assistance scale are their... In sooty mold fungi which will result in a body several times greater the... Are some control options beetle feed on scale eggs and the cottony-cushion scale when they feed on scale! General types of scale– armored scale and soft scales or mealybugs weeks in warm weather Tiger ) as result... Within a few days after mating as they are unable to feed, contact your local Cooperative Extension for!