However, over-fertilization favors scale buildup. Horticultural oil can be used in winter when trees are without leaves to smother females living on branches. Cottony maple leaf scale is found throughout the eastern United States and southern Canada. If practical, improve plant sites to reduce stress and promote growth. The cottony maple scale is most easily recognized by the characteristic egg masses on twigs and branches. The distinguishing characteristic of these soft scales is the white egg sac (ovisac) produced by female scales in summer. Find more information at the following NC State Extension websites: Publication date: Aug. 1, 2010 Cottony maple leaf scale females are 3 to 4mm long and 2 to 4mm wide. Damage to the host tree is caused when heavy populations of cottony maple scale withdraw sap from the plant, resulting in branch and twig dieback. After mating, the females crawl to the leaves to lay eggs. Honeydew often drops onto leaves or plants below. Be sure to obtain current information about usage regulations and examine a current product label before applying any chemical. It also is known to survive on other species of maple, honey and black locust, white ash, euonymus, oak, boxelder, dogwood, hackberry, sycamore, beech, elm, willow, basswood, and poplar. Cottony maple scale reaches epidemic numbers on silver maple, but noticeable populations can occur on red maple. They are also called cottony taxus scales as this scale is a fairly common pest of yew. Because environmental conditions and methods of application by growers may vary widely, performance of the chemical will not always conform to the safety and pest control standards indicated by experimental data. The scale overwinters as an immature female on the twigs of the host. COTTONY MAPLE SCALE Lee Townsend, Extension Entomologist A mature female cottony maple scale is 1/8" long, and has a brown, flat, oval body. A lady beetle larva will move, albeit slowly, when poked or prodded; a scale egg mass will not. As the scale eggs hatch, the lady beetles leave, apparently to look for other prey. Consequently, they may not be effective where several l… Only one generation of cottony maple scale occurs each year. Cottony Maple Scale starts off as an unnoticeable, brown scale. Cottony Maple Leaf Scale is one of several cottony scales in the genus Pulvinaria. Recommendations for the use of agricultural chemicals are included in this publication as a convenience to the reader. Common hosts in California are citrus, cocculus, nandina, and pittosporum. Mature females are pale to dark brown, convex, and about 3-6 mm long (Fig. — Read our Types of Cottony Maple Scale There are many types of scale insects and several of those produce a white cotton-like mass. N.C. Although a heavy infestation may cause some thinning of the canopy, it rarely results in tree death. Scales tend to thrive on stressed plants. Dave Smitley, Michigan State University, Department of Entomology - May 21, 2010. In extreme conditions, a tree may be killed. It looks very similar to the egg mass of the cottony maple scale. This scale looks like cotton balls attached to the stem. Cooperative Extension county center. Nymphs are brown-translucent, 1/5 inch; females lay eggs in the white marshmallow egg-sac along the twigs and small branches; Young insects remove sap from leaves creating a speckled appearance and possibly yellowing leaves in mid to late summer Unfortunately, the predators and parasites are susceptible to many insecticides used in the landscape and are often eliminated before they can adequately control the scale. Receive Email Notifications for New Publications. Immature lady beetles are gray but soon become covered with a thick, cottony covering of wax that makes them look like mealybugs. Therefore, systemic provide much longer control than contact insecticides and can kill all feeding stages. commitment to diversity. scales. Cottony maple scale is being found in DuPage, Livingston, and Grundy counties, on silver maple, sugar maple, honeylocust, green ash, and hawthorn. If abundant, a sooty mold fungus may colonize the honeydew, resulting in a black sooty appearance on the leaves, twigs, and branches. Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Severely prune back heavily infested branches and protect new growth with insecticide applications. Cooperative Extension prohibits discrimination and harassment regardless of age, color, disability, family and marital status, gender identity, national origin, political beliefs, race, religion, sex (including pregnancy), sexual orientation and veteran status. Adults were present in mid-May; I photographed one in my backyard in central Illinois at that time. Cottony maple scales will produce white cottony egg sacs by mid-June. In April, male scales develop into tiny, winged, gnatlike insects which mate with females and then die. Crawlers are extremely small and appear as yellow-orange moving dots. Cottony camellia scale is a soft scale that feeds on camellia, holly, yew, euonymus, sweetbox, and maple. In early summer mature females begin to secrete white, waxy, cottony-appearing egg sacs in which they lay as many as 1,500 eggs. Heavily infested trees have small flowers and leaves. (76) Photo: John Davidson be controlled as crawlers and immatures. Check the label of any pesticide referenced to ensure your use is included. A close examination of the ovisacs reveals the eggs are held inside a sack-like matrix of sticky, silk-like material. Cottony maple scale is a lecanium-type scale, being very similar in appearance to European fruit lecanium for most of the year. Other treatments should aim to control crawlers on foliage in July, when they first become active. NC State University and NC Consequently infested trees are stunted and appear scorched and black. The presence of this Insect le easily discovered during the summer months because of the white cottony masses about the size of peaa that are found on the lower sides of the limbs, especially those near the ground. The cottony maple scale (Pulvinaria innumerabilis) is one of the largest and most conspicuous scale insects in this country. It is also known as cottony taxus scale. Infested trees are rarely killed, but heavy infestations may cause dieback of individual branches and a general decline in plant vigor. Cottony scales suck sap from leaves (summer) and twigs (fall, winter, early spring) depriving the tree of valuable resources. Pulvinaria innumerabilis (cottony maple scale) is a small, flattened, brown scale insect about 1/8" long. The cause of this annoyance is a tiny insect known as Cottony Maple Scale. The rest of the time the scale is present but in numbers too low to attract attention. Inappropriate timing is not only ineffective, but Do not use acephate on red or sugar maple. A&T State University. Revised: Sept. 18, 2019. In late September, just before leaf drop, fertilized female nymphs migrate from the leaves to twigs and branches, where they overwinter. The "cotton" is actually a waxy secretion enveloping the ovisac, which may contain over 1,500 eggs. Older scales are dark brown. Cottony maple scale outbreaks often subside in … During June, the inconspicuous female scales that spent the winter on the stems expand and begin producing a large, white, cottony egg sac. These eggs hatch from mid-June to August, and the young nymphs called scale crawlers emerge… Both scales produce white, cottony ovisacs, and both have wide host ranges; however, as its common name implies, cottony maple leaf scale produces its ovisacs on the underside of its host's leaves. The white cottony egg masses, which resemble popcorn, are the most distinguishing feature of this scale. At maturity, the females produce the white, cottony egg masses, called ovisacs, over a period of several weeks. In April and May, cottony maple leaf scales move to the leaves and lay up to 2,500 eggs in cottony ovisacs on the undersides (Figure 3 and Figure 4). They are black, flat, and oval. Crawlers, as their name implies, crawl to the underside of leaves, where they settle and feed on the sap. N.C. Treatments for Calico scale, cottony maple scale, and Lecanium spp. The twice-stabbed ladybeetle, which feeds on soft-bodied insects, is commonly found dining on cottony maple scale crawlers. Figure 2. (Other contributors to this article: Mary Pfeiffer, Grundy County Extension Unit; Mary Shier, Livingston County Extension Unit). Adult twice-stabbed lady beetles are about 1/8 inch long, roundish, and black, with two red spots on the back. In the spring, a white egg sac is developed and holds many crawlers (insect). The following pesticides are effective for control of cottony maple leaf scales. The cottony maple scale is a large, flat, brown scale insect found on the twigs and branches of various trees. Adult females are about 3/16 inch long. The cottony maple leaf scale is so named because the females exude their eggs in an elongated, white, cottony structure called an ovisac which are stuck onto the underside of leaves. Cottony maple scale is a food source for many predaceous insects and parasites. Their eggs are white to pale yellow and are meshed in a white, cottony ovisac which may be up to 5mm wide and 12mm long. The insect overwinters as a female scale. Foliar applications should target crawlers. They become active and feed on the leaves between June and July. When we do see it, however, the show is spectacular. G = greenhouse, N = nursery, L = landscape, I = interiorscape. Cottony maple leaf scale females are 3 to 4mm long and 2 to 4mm wide. Cottony Maple Scale. Cottony Scales include Cottony Camellia Scale (Hollies and verious other plants), Cottony Taxus Scale (Yews), Cottony Maple Scales (Silver Maple, Dogwood and others) and Azalea Bark Scale (Azalea, Andromeda and Rhododendron). Individuals who use agricultural chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. You can find these now on their most common hosts: maple and dogwood. Eggs masses are conspicuously white and cottony in appearance. Severely infested trees look like they are covered with strings of popcorn. commitment to diversity. Immature females are flat and inconspicuous. It has also been reported from some western states. Newly hatched nymphs are pale yellow or green and translucent. In late spring and early summer, females produce conspicuous cottony egg masses that may contain more than 500 eggs. Foliar applications of acephate (Orthene), malathion, or summer horticultural oils to the underside of the leaves should provide effective control of cottony maple scale. Eggs hatch into the crawler stage of the scale in late June and early July in central and northern Illinois. The 1/4-inch white cottony ovisac, or egg sac, is deposited on bark. A favored host is silver maple, but it will attack other species of maple as well. In severe infestations of cottony maple scale, chemical control may be desirable. After leaves open thorough coverage is very difficult. Cottony camellia scale and cottony maple scale are the other common species. Cottony maple scale is sometimes mistaken for Cottony Maple Leaf Scale (P. acericola). They are slightly convex and are brown with a yellow-brown ridge down the back (Figure 1). .• Insecticidal Sprays Horticultural oils kill by suffocation or after penetrating over-wintering stages of the insect. Leaves may turn yellow and drop prematurely. Its cottony egg sac and profuse honeydew production make cottony cushion scale easy to spot in the landscape. Male scales mature in late August and early September, when they mate with immature females and die. The twice-stabbed ladybeetle, which feeds on soft-bodied insects, is commonly found dining on cottony maple scale crawlers. The Soft Scales (Homoptera : Coccoidea : Coccidae), The soft scale insects of Florida (Homoptera: Coccoidea: Coccidae), Soft Scale Identification and Management on Ornamental Plants, NC State Extension Plant Pathology Publications and Factsheets, NC State Horticultural Science Publications, Entomology – Insect Biology and Management, NC These cottony masses can contains hundreds of eggs each. In late summer, the scales crawl to the twigs where they feed for the rest of the fall, winter and early spring. Cottony camellia scales, Pulvinaria floccifera, are cream to tan, elongate oval, and relatively flat. There is one generation each year. See the North Carolina Agricultural Chemicals Manual for additional insecticide choices. Cottony Maple Scale. They excrete honeydew in which can grow sooty mold. The cottony maple scale is a pest on certain shade trees, particularly black locust and soft maple. Adult females are about 1/8 inch long, oval and yellowish tan with a brown margin. During the dormant season, twice-stabbed lady beetles overwinter as adults under loose bark where they are not affected by the spray. Infestations of this magnitude can occur on silver maple but are less likely to occur on other hosts. The cottony maple scale is common on maple, boxelder, hackberry, dogwood, beech, apple, oak, linden, honeylocust, and elm. Its favored host is maple trees, although it has been found on a number of other species as well. Cottony maple leaf scale damage. Contact insecticides such as pyrethroids may provide less consistent control because they rely on contacting the insect whereas systemics make the plant toxic for the insect to feed on. Heavy infestations of this scale may cause yellowing, wilting and eventually branch dieback. Crawlers hatch in late May to early June and feed on the underside of the host leaves, usually along the ribs of the leaf. The body is covered with flakes of clear wax. Mature cottony maple scales are small, flat, oval, brown insects without obvious legs, antennae or wings. Repeat treatments may be needed after ten days. Many systemic products are available that can be applied as foliar spray or drench. A close examination of the ovisacs reveals the eggs are held inside a sack-like matrix of sticky, silk-like material. Identify cottony maple scale (Pulvinaria innumerabilis), the most common scale insect species to infest maple trees, by their adult female scales with cotton-like egg sacks on their hind ends. Mature female scales are brown, roundish, and about one-quarter inch in diameter. This is the substance that makes our cars, sidewalks, decks, you name it, sticky in the summer. And they will ruin your citrus, unless you get it under control. Dormant-oil treatments control overwintering female nymphs on most hosts (except sugar and Japanese maple) after leaf drop in the fall and before budbreak in the spring. Figure 4. Cottony maple scale is a food source for many predaceous insects and parasites. As its name suggests, cottony maple scale (Pulvinaria innumerabilis) affects mostly maple trees (predominantly silver and red maples). Recommendations of specific chemicals are based upon information on the manufacturer's label and performance in a limited number of trials. Pulvinaria innumerabilis. One of the insects we see on rare occasion in Iowa is the cottony maple scale. Cottony maple scale definition is - a brown oval soft scale (Pulvinaria innumerabilis) that in summer becomes covered with a white cottony secretion beneath which its eggs are laid, that is widespread in North America, and that attacks and often kills various native and cultivated trees and shrubs. They are slightly convex and are brown with a yellow-brown ridge down the back (Figure 1). Cottony cushion scale, Icerya purchasi, can infest a number of woody ornamentals and certain crops (Figure 1). The crawler's waste is called honeydew. A&T State University, in all 100 counties and with the Eastern Band of Cherokee List of files and visuals associated with this text. Several parasites and predators have been reported for the cottony maple leaf scale. Crawlers appear in June and immatures in summer on the underside of leaves. This insect is active throughout the United States and attacks many shade trees and shrubs, but it is primarily found on soft Maples and Lindens. Each mass usually contains 1,000-1,500 eggs. It�s common for both larvae and adults to be present at the same time. Cottony Cushion originates from Australia and is rumored to have come to the US by accident in the late 1800’s on a plant shipment. One spray during that period should be sufficient. In heavy infestations, leaves may be stuck together, and the ground beneath the trees may be extremely sticky. Immature forms (crawlers) are flattened and brown to yellowish green in color; however, the conspicuous, cottony egg sac of the mature female is two to three times the length of the scale … 1). The full-grown larva is about 1/4 inch long, whitish to grayish, and covered with waxy filaments. Twig dieback may occur resulting in sparsely foliated canopy (Figure 2). For assistance, contact your local N.C. It is also reported on beautyberry, jasmine, mulberry, and hydrangea. Timing pesticide application to the crawler stage is very important. At this time of year, beetles are usually in the larval stage. The body is covered with flakes of clear wax. Egg sacs may grow to as large as 1/2 inch in diameter and may contain up to 1000 eggs. Egg sacks appear as white cottony masses emerging from beneath the brownish scale covers of females. Following a recommended fertility program and watering regime will promote plant health. Cottony Maple Scale . Before treating for crawlers, look for twice-stabbed lady beetles. Pest description and crop damage The cottony maple scale is one of the largest soft scales. This scale feeds primarily on maple and dogwood in North Carolina, but it also infests hollies, Andromeda, and gum. These egg-laying scales do not feed and they soon die. Immatures overwinter on twigs. Sooty mold is commonly found growing on the honeydew in mid- to late summer. Cottony maple scale outbreaks often subside in two to three years, due to control by natural enemies. Cottony Cushion Scale had taken over, right under my nose! This publication printed on: Dec. 26, 2020, The Scale Insects of California: Part 1. These little buggers are so tiny and sneaky. Young females have a dark stripe down the middle and mottling at the sides. After crawlers begin feeding on leaf sap they can create enormous amounts of honeydew. Indians. Adults are usually present in July when the crawlers are present. Cottony maple scale crawlers along leaf veins in the summer. Imidacloprid, a systemic insecticide, only controls soft scales. Egg sacks look like popcorn on the underside of small branches on the scale�s primary host (silver maple), other maples, alder, apple, beech, black locust, box elder, dogwood, elm, euonymus, honeylocust, linden, mulberry, oak, osage orange, peach, pear, plum, poplar, rose, sumac, and sycamore. If larvae and/or adults of this lady beetle are present in reasonable numbers, it�s best to avoid spraying for cottony maple scale crawlers. To monitor for this pest, look for tiny (1/8 inch long), oystershell shaped, and brown to gray scale covers on the bark of wilting or dead branches. In some cases, the scales are quite numerous. Every 5 to 10 years we experience an "outbreak" of cottony maple scale somewhere in the state. These lady beetles and their larvae feed on the scale eggs in the ovisacs. They closely adhere to the undersides of leaves and are easily overlooked. Female scales mature when plant growth resumes in the spring. Adult lady beetles are black with small orange spots. The Cottony Maple Scale. Infestations are most easily noticed during the summer when females produce white, cottony egg sacs that resemble pieces of popcorn on a twigs. In spring the female matures and lays eggs. Cottony Scale insects produce cottony egg masses from which young crawlers emerge. Cooperative Extension is based at North Carolina's two land-grant institutions, Their eggs are white to pale yellow and are meshed in a white, cottony ovisac which may be up to 5mm wide and 12mm long. For assistance with a specific problem, contact your local Cooperative Extension center. Drench applications should be made when eggs are present so the tree can take up the material by the time crawlers become active. The scale itself is about 1/4 inch, and the egg sack is about 1/2 inch in size. Honeydew is the sugary, liquid waste excreted by scale insects. Cottony ovisac on maple leaf with desiccated adult female present. Thus by mid-June, the scale eggs have hatched, the crawlers are exposed on the undersides of leaves and the lady beetles are gone. The eggs hatch in late June and July and the crawlers move to the leaves. This is the optimum time for control. This is an armored scale and, unlike the cottony maple and calico scales, it does not produce honeydew. These scales also produce large amounts of liquid waste Frequently, feeding results in the secretion of a clear sticky substance called honeydew. Cottony maple scale overwinters as immature females (nymphs) on twigs and branches. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by NC State University or N.C. A&T State University nor discrimination against similar products or services not mentioned. Male scales are tiny, winged insects. IDENTIFICATION AND LIFE CYCLE They are firmly attached to the twigs and branches of various trees and may be ¼ to ⅜ inch in diameter. The most abundant are in a group of small lady beetles in the genus Hyperaspis. Scale insects tap into plants and feed on plant sap, weakening and even killing plants over time. The biggest problem is the honeydew dripping down on decks, picnic tables, lawn chairs and parked cars. Read our Cottony maple scale is most easily noticed in late spring. The cottony maple leaf scale is so named because the females exude their eggs in an elongated, white, cottony structure called an ovisac which are stuck onto the underside of leaves. Cottony maple scale Pulvinaria innumerabilis. There is one generation a year. Spray when the temperature will stay above freezing for 24 hours after the spray. They spend the winter in an immature stage on twigs or branches and complete development in June when the egg sacs appear. Cottony maple scales commonly infest silver maple but can feed on several species including other maples, boxelder, basswood, birch, elm, and linden. One symptom of heavy infestations of cottony maple scale is honeydew. By late spring the insect has developed into a mature female and begins laying as many as 1,000 eggs. Products are available that can be used in winter when trees are without leaves to twigs and branches of trees! 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Insects of California: Part 1 ( cottony maple scale is a fairly common pest of yew inch. Adult twice-stabbed lady beetles in the larval stage of scale insects a tree may be killed be controlled crawlers. Too low to attract attention armored scale and, unlike the cottony scale... Mostly maple trees, particularly black locust and soft maple of yew for ensuring that the intended use complies current... Carolina, but heavy infestations of cottony maple leaf scale is a fairly common of! Predominantly silver and red maples ) to tan, elongate oval, and maple just before leaf drop fertilized! Usage regulations and examine a current product label appear in June and immatures whitish to grayish and... Contain more than 500 eggs yew, euonymus, sweetbox, and about one-quarter inch in size cottony maple scale for! At maturity, the females crawl to the undersides of leaves and are easily overlooked will.