51. The solenopsis mealybug feeds on the foliage of its host in summer and the roots in winter, and large numbers of scale species feed invisibly, year-round on roots. The fact that a new population can be founded by a single individual may have contributed to the success of the cottony cushion scale which has spread around the world. scale insects in the state of Florida, a range of products have been listed by Buss and Turner (2006). Ben-Dov, Y. Of dramatically variable appearance and extreme sexual dimorphism, they comprise the superfamilyCoccoidea. This page was last edited on 1 December 2020, at 20:41. Some common Florida scales. It has been a pest of Ixoraspp.  The diversity of systems has made scale insects ideal models for research. Besides sexual reproduction, a number of different forms of reproductive systems are employed, including asexual reproduction by parthenogenesis. Eggs: The eggs are pink to dark red and they are laid under the adult female scale's wax covering. To do this they usually walk, as their ability to fly is limited, but they may get carried to new locations by the wind. Scale insects are usually divided into two groups: soft scale, and hard or armored scale. The best agent however is a small wasp parasite called Anicetus beneficus. Prior to the Florida discoveries, the California Department of Food and Agriculturâ¦ Hamon AB, Williams ML. These small insects vary a lot in size (from 1/16 to 3/8 inch across) and appearance but all grow beneath a wax covering that resembles an individual reptile or fish scale, hence the common name. , One species, the cottony cushion scale, is a serious commercial pest on 65 families of woody plants, including Citrus fruits. Texas Cooperative Extension, The Texas A&M University, College Station, TX. There are many scale insect species that infest ornamental landscape plants. Older nymphs can move around within the same plant to search for new flushes of growth on which to feed. Most soft scales present in Australia are native. Eggs:The eggs are pink to dark red and they are laid under the adult female scale's wax coverâ¦ They are: Coccophagus lycimnia (Walker) (Aphelinidae), Metaphycus eruptor Howard (Encyrtidae), and Scutellista cynea Motschulsky (Pteromalidae) (Drees et al. Scale insects can be difficult to get rid of but spraying with PLANThealth Spectrum and/or Organic Insect Control followed by Organic Super Spraying Oil is most effective, killing scale through suffocation. Cultural control. The vestigial wings are often reduced to pseudo-halteres, club-like appendages, but these are not homologous with the control organs of Diptera, and it is not clear whether they have any substantial control function.  Scale insects secrete a large quantity of sticky viscid fluid known as "honeydew". Figure 3. Silk scarlet cloth dyed with kermes, made from female Kermes scales, The scale insects are members of the Sternorrhyncha. Insects That Feed on Trees and Shrubs, 2nd ed.. Cornell University Press. Mass rearing of the Florida wax scale, Ceroplastes floridensis,for production of natural enemies.  Both the colour name "crimson" and the generic name Kermes are from Italian carmesi or cremesi for the dye used for Italian silk textiles, in turn from the Arabic qirmizÄ« (ÙØ±Ù Ø²), meaning both the colour and the insect. Three parasitoids are known to attack Florida wax scales in some parts of the United States. L-5479. , Collecting scale insects from a prickly pear for a dyestuff, cochineal, 1777, Coronation cloak of King Roger II of Sicily, 1133. Hodges GS, Ruter JR, Braman SK. The commonest (known as the lecanoid system) involved deactivation of the paternal genome and elimination at the time of sperm production in males, this is seen in Pseudococcidae, Kerriidae and some Eriococcidae. They became widespread and common in the Cretaceous, and are well represented in the fossil record, usually preserved in amber where they are sometimes associated with ants. In some species the hind wings have hamuli, hooklets, that couple the hind wings to the main wings, as in the Hymenoptera. Here the mealybugs are safe from predation and environmental hazards, while the ants have a source of nourishment. There are other different types of scale and some scale insects are host specific, such as rose scale, white palm scale, gum tree scale and tea scale (camellias). Florida wax scale is thought to have originated from the northern Neotropical region and now occurs throughout the world, including, but not restricted to, the following countries: Africa: Algeria, Egypt, Kenya, Libya, Madagascar, Madeira, Mauritius, Morocco, Mozambique, Seychelles, Sierra Leone, Sudan, Tanzania, Uganda, Asia: Bonin Islands, Brunei, China, Cyprus, India, Iran, Israel, Japan (including the Ryukyu Islands), Korea, Lebanon, Malaysia, Pakistan, Sri Lanka, Syria, Taiwan, Turkey, and the more southern member countries of the former Union of Soviet Socialist Republics, Australasia and Pacific Islands: Australia, Caroline Islands, Mariana Islands, New Zealand, Central America and Caribbean: Costa Rica, Guatemala, Honduras, Panama, West Indies, Europe: France (including Corsica), Greece, Italy (including Sicily), Malta, Spain, South America: Brazil, Colombia, Ecuador, Guyana, Venezuela. These insects deposit their secretions on the branches of certain species of Ligustrum (privet) tree. In other instances, scale insects are carried inside the ant's nest; the ant Acropyga exsanguis takes this to an extreme by transporting a fertilised female mealybug with it on its nuptial flight, so that the nest it founds can be provisioned. 117 pp. Sooty mold on holly leaves. Nymphs: The first instars are pink in color and have functional legs. , Scale insects are an ancient group, having originated in the Cretaceous, the period in which angiosperms came to dominance among plants, with only a few groups species found on gymnosperms. In Parthenolecanium, males are born from unfertilized eggs but diploidy is briefly restored by fusion of haploid cleave nuclei and then one sex chromosome is lost through heterochromatinization.  Fungi in the genus Septobasidium have a more complex, mutualistic relationship with scale insects. Avoiding toxic pesticides and creating the right environment for beneficial insect to thrive are important to good scale management. Some, such as the cochineal, kermes, lac, Armenian cochineal, and Polish cochineal, have been used to produce red dyes for coloring foods and dyeing fabrics. The evolution of these systems are thought to be the result of intra-genomic conflict as well as possibly inter-genomic conflict with endosymbionts under varied selection pressures. Recognition of scale insect families has fluctuated over time, and the validity of many remains in flux, with several recognized families not included in the phylogeny presented above: Families known only from fossils are Albicoccidae, Burmacoccidae, Arnoldidae, Electrococcidae, Grimaldiellidae, Grohnidae, Hammanococcidae, Inkaidae, Jersicoccidae, Kukaspididae, Labiococcidae, Lebanococcidae, Lithuanicoccidae, Macrodrilidae, Pennygullaniidae, Serafinidae and Weitschatidae.. Scale insects in the family Coccidae require specialist skills for their identification, but the adult females of the three species of Ceroplastes in New Zealand can be recognised by their thick covering of wax. In the other variant or Comstockiella system, the somatic cells have the paternal genome untouched. The Florida wax scale, Ceroplastes floridensis Comstock, is one of the most commonly encountered soft scales throughout the southern United States, where it is a serious pest of citrus and several ornamental plants, like holly. Adult females typically have soft bodies and no limbs, and are concealed underneath domed scales, extruding quantities of wax for protection. 536 pp. Scale insects are herbivores, piercing plant tissues with their mouthparts and remaining in one place, feeding on sap. In 2013, we added Indian wax scale, white prunicola scale and juniper scale to the monitoring list to better determine crawler periods. Buss EA, Turner JC. In Iowa, most species of shade trees, fruit trees, and ornamental shrubs are subject to scale insect attacks. Adult females typically have soft bodies and no limbs, and are concealed underneath domed scales, extruding quantities of wax for protection. In some species, sexual and asexual populations are found in different locations, and in general, species with a wide geographic range and a diversity of plant hosts are more likely to be asexual. In the United States, it occurs from New York to Florida and west to New Mexico (Hamon and Williams 1984). Males are not known in this species (Futch et al. Of the predatory insects both lacewings and cryptolaemus ladybird beetles will feed on this pest. Each female has a reddish body that is coated with a thick layer of pinkish-white wax. Scale insects with hardened wax coverings that detach easily from their soft bodies underneath are referred to as âhardâ or âarmoredâ scales (Fig. Field Key The general descriptions of the scale insects in the following key is largely based on Hamon and Williams (1984) and Dekle (1976). 2). and Malumphy, C. (2013). Adult females are almost always immobile (apart from mealybugs) and permanently attached to the plant on which they are feeding. Coffee scale is a major agricultural pest in coffee crops. Susceptibility of. Order: Homoptera Description: âWaxâ scales are globular and coated with an heavy layer of wet beige, pinkish, whitish or grayish wax. Males, in the species where they occur, have legs and sometimes wings, and resemble small flies.  In 1990, they caused around $5 billion of damage to crops in the United States. The brown soft scale is an exception; it has multiple generations and females and nymphs can be present throughout the year. This is seen in the genus Icerya. Arthropods of Florida and neighboring land areas, Vol. In more primitive families there is an additional instar stage. Where there are several generations in the year, there may be a general retreat onto the twigs as fall approaches. Anicetus wasps deposit their eggs into the scale insect and the larval stage â¦ 2012. Adults:Adult female Florida wax scales are elliptical, reddish brown with a short anal process (Hamon and Williams 1984), and range from 2 to 4 mm in length and 1 to 3.5 mm in width. Florida wax scales: Control measures in Texas for hollies. The species is a major commercial pest of crops such as Citrus fruits. The waxy covering of many species of scale protects their adults effectively from contact insecticides, which are only effective against the first-instar nymph stage known as the crawler. A systematic revision of the wax scales, genus. These citrus scale pests not only wreak the havoc mentioned above, but the armor will also remain on the plant or fruit long after the insect is dead, creating disfigured fruit. Large population size is hypothesized to protect an asexual population from becoming extinct, but nevertheless, parthenogenesis is uncommon among scale insects, with the most widespread generalist feeders reproducing sexually, the majority of these being pest species. Their closest relatives are the jumping plant lice, whiteflies, phylloxera bugs and aphids. , Scale insects have various natural enemies, and research in this field is largely directed at the species that are crop pests.  Ants looking after their providers of honeydew tend to drive off predators, but the mealybug destroyer has outwitted the ants by developing cryptic camouflage, with their larvae mimicking scale larvae. When planting, install them in a location that is suitable to their duration of light and soil type needs. , Palaearctic "Eriococcidae" (felted scales), Beesoniidae, Stictococcidae, part of "Eriococcidae". Crawler (pink instar - second from right) and settled nymphs of the Florida wax scale, Ceroplastes floridensis Comstock. In Florida, it also infests a variety of other plants, including: The direct damage is caused by nymphs inserting their mouthparts into the plant tissue and withdrawing large amounts of plant fluids. They are mainly found on plant stems. The sooty mold can cause a significant reduction in photosynthesis and aesthetic value (Hodges et al. In some Diaspididae and Pseudococcidae, both sexes are produced from fertilized eggs but during development males eliminate the paternal genome and this system called paternal genome elimination (PGE) is found in nearly 14 scale insect families. A third variant found in Diaspididae involves the paternal genome being completely removed at an early stage making males haploid both in somatic and germ cells even though they are formed from diploids, ie from fertilized eggs. Scale insects and mealybugs on ornamental plants. 2009). This wax generally forms a protective covering that may or may not be attached their body. Photograph by Lyle J. Buss, University of Florida. Most common in the soft scale genus Ceroplastes. Plant death is also possible. Most species have wings, and in some, alternate generations may be winged or wingless. in width. Systemic insecticides applied to the soil as a drench or sprayed onto foliage can effectively control scale infestations. Common examples include azalea bark scale, Magnolia scale, Indian wax, cottony camellia scale, and European fruit lecanium. The traditional division into "Archaeococcoids" and "Neococcoids" is preserved except that the genus Pityococcus is moved to the "Neococcoids". Other species of wax scales include tree dwellers like the cottony maple scale (Pulvinaria innumerabilis) or the calico scale (Eulecanium cerasorum). Soft scale (for example pink wax scale and soft brown scale) are usually found on the mid-rib of leaves and stalks of host plants. Some species are used for biological control of pest plants such as the prickly pear, Opuntia. 356 pp. , The first instars of most species of scale insects emerge from the egg with functional legs, and are informally called "crawlers". Some species are hermaphroditic, with a combined ovotestis instead of separate ovaries and testes. Legs are absent in the females of some families, and when present vary from single segment stubs to five-segmented limbs. A cladogram showing the major families using this methodology is shown below. Scale insect, any member of several families of insects (order Homoptera) that have a body covered by a protective waxy shell, often resembling scales or cottony cushions.The waxy covering is secreted by the insect after it settles on the plant where it will feed. Wait 24 to 36 hours â¦ The majority of female scale insects remain in one place as adults, with newly hatched nymphs, known as "crawlers", being the only mobile life stage, apart from the short-lived males. 2006). Chemical control.  Several other monophagous scale insects, especially those on islands, are threatened by coextinction due to threats faced by their host plants. There are three instars (Drees et al. "A review of the Irish scale insects (Hemiptera: Coccoidea)". Figure 2. Biological control. Underneath the wax cap, the body of the scaâ¦ The young nymphs of these scale insects are also distinctive. See also anal tube sclerotization. A range of predators and parasites will attack pink wax scale. , In species with winged males, generally only the forewings are fully functional. Both the red colour-names crimson and scarlet derive from kermes products. Prune off and destroy any infested plant parts. Many species produce a thick convex wax layer, but others do not. Viewed from the top, they are rectangular, oval or lobed at the base. The fungus lives on trees where it forms a mat which overgrows the scales, reducing the growth of the individual parasitised scales and sometimes rendering them infertile, but protecting the scale colony from environmental conditions and predators. Males are not known in this species (Futch et al. 9. 2 ï»¿ Armored scale secretes a hard shell over its body for protection from predators. There are many variations on such themes, such as scale insects that are associated with species of ants that act as herders and carry the young ones to protected sites to feed. ", "Aphids and scale insects on threatened trees: co-extinction is a minor threat", "A new species of ant-tended soft scale of the genus, "An ancient tripartite symbiosis of plants, ants and scale insects", "Guidance for Industry: Cochineal Extract and Carmine", "New Termitaphididae and Aradidae (Hemiptera) in Mexican and Dominican amber", "Putting scales into evolutionary time: the divergence of major scale insect lineages (Hemiptera) predates the radiation of modern angiosperm hosts", "Phylogeny and higher classification of the scale insects (Hemiptera: Sternorrhyncha: Coccoidea)", 10.1206/0003-0082(2001)335<0001:AAAAHF>2.0.CO;2, Cottony cushion scale: the pest that launched a pest control revolution, Scales of southeastern U.S. woody ornamentals, Institute of Food and Agricultural Sciences, https://en.wikipedia.org/w/index.php?title=Scale_insect&oldid=991787310, Extant Early Cretaceous first appearances, Srpskohrvatski / ÑÑÐ¿ÑÐºÐ¾Ñ ÑÐ²Ð°ÑÑÐºÐ¸, Creative Commons Attribution-ShareAlike License. These red scales have made themselves right at home on these marijuana leaves ScaleNet: a database of the scale insects of the world. Tea scale insects are about the size of a hyphen, appear slightly fuzzy and are white or brown. 1974. Oil sprays can be an effective tool as a soft option for helping reduce scale insect â¦ Scale insects also secrete a sticky liquid called honeydew, which promotes the fungal disease black sooty mold. Some scale insects are serious commercial pests, notably the cottony cushion scale (Icerya purchasi) on Citrus fruit trees; they are difficult to control as the scale and waxy covering protect them effectively from contact insecticides. The family Beesoniidae lacks antennae, but other families possess antennae with from one to thirteen segments. In some species they delay settling down either until they are starving, or until they have been blown away by wind onto what presumably is another plant, where they may establish a new colony. The color is white, sometimes with a pinkish cast, becoming â¦ Some species are hermaphroditic, with a combined ovotestis instead of separate ovâ¦ Horticultural Oil Precautions Test the spray on a leaf or two. Adult female cottony cushion scale (Icerya purchasi) with young crawlers. This scale is considered a major pest of citrus (Citrus spp.)  A Hawaiian mealybug Clavicoccus erinaceus that fed solely on the now critically endangered Abutilon sandwicense has gone extinct as has another species Phyllococcus oahuensis. The mouthparts are adapted for piercing and sucking. This includes sugars, amino acids and minerals, and is attractive to ants as well as acting as a substrate on which sooty mould can grow. They immediately crawl around in search of a suitable spot to settle down and feed. Scale insects feed on shrubs' sap using their long, piercing mouthparts, causing twig and branch dieback and sometimes killing the plants. Adults: Adult female Florida wax scales are elliptical, reddish brown with a short anal process (Hamon and Williams 1984), and range from 2 to 4 mm in length and 1 to 3.5 mm in width. They are a major pest of camellias and some hollies. 1984. In either case, many such species of crawlers, when they moult, lose the use of their legs if they are female, and stay put for life. Wax scale insects; Many scale insects have effective natural enemies, some of which are commercially available. Adult Florida wax scales, Ceroplastes floridensis Comstock. Each female has a reddish body that is coated with a thick layer of pinkish-wâ¦ Photograph by Lyle J. Buss, University of Florida. Entomopathogenic fungi can attack suitable scales and completely overgrow them. Florida wax scale is highly convex, somewhat angular, and oval. Photograph by Eileen Buss, University of Florida. Most common is white wax scale, seen as large patches of white waxy material along the stems and shoots. Florida Agricultural Experiment Station. Ben-Dov, Y. Scale insects come in many types, but here are a few of the most common. Some scales may remain on the plant, dead, after being treated with an insecticide. There are systemic insecticides available that can be used to control scale. They showed that the main scale insect lineages diverged before their angiosperm hosts, and suggested that the insects switched from feeding on gymnosperms once the angiosperms became common and widespread in the Cretaceous. Soft scale is covered with a protective waxy substance and is somewhat easier to kill than hard/armored scale. Use the proper amount of irrigation and fertilization based on the needs of the particular plant species or variety (Drees et al. (April 2009). Lecanium scale â The oak lecanium scale is abundant on willow oaks and other oak species (Figure 3). Drees BM, Reinert JA,Williams ML. The tiny parasitic wasp Anagyrus lopezi, a highly effective biological control of the cassava mealybug, At the same time, some kinds of scale insects are themselves useful as biological control agents for pest plants, such as various species of cochineal insects that attack invasive species of prickly pear, which spread widely especially in Australia and Africa. Wax and all, they are about 1 / 4 inch long. 2009). Gossard HA. , Scale insects show a very wide range of variations in the genetics of sex determination and the modes of reproduction. This is unusual among insects; it most closely resembles the situation in the true flies, the Diptera. , Most scale insects are herbivores, feeding on phloem sap drawn directly from the plant's vascular system, but a few species feed on fungal mats and fungi, such as some species in the genus Newsteadia in the family Ortheziidae. They are usually slender insects resembling aphids or small flies. Wax scale can be 3-8mm in diameter and are white, cream, pink, or gray. throughout its range. 2006a). It has spread worldwide from Australia.. Figure 4. Scale insects are sap-feeding insects named for the scale or shell-like waxy covering that conceals their bodies. The eggs are ovoid, pale purple, and resemble pollen when shaken onto a white surface. Scale insects vary dramatically in appearance, from very small organisms (1â2 mm) that grow beneath wax covers (some shaped like oysters, others like mussel shells), to shiny pearl-like objects (about 5 mm), to animals covered with mealy wax. On these, males often feed on the leaves, usually beside the veins, while females select the twigs. Others attack a variety of hosts such as white wax scale occurring on gardenias and citrus; and cottony cushion scale occurring on figs, rose, magnolias, grevilleas and â¦ As scale insects grow, many species exude wax from pores on their bodies. The second and third instars secrete a wax covering around them, giving them a star-like appearance. Only the males retain legs, and in some species wings, and use them in seeking females. As a result of the scales consuming so much plant fluid, they excrete a considerable amount of a sugary, sticky honeydew, which then becomes colonized by a sooty mold fungus (Argov et al. Of dramatically variable appearance and extreme sexual dimorphism, they comprise the superfamily Coccoidea. Their dispersal ability depends on how far a crawler can crawl before it needs to shed its skin and start feeding. The first generation occurs in April and May, the second is in July and August, and the third one occurs in October and November. Their phylogeny within that group, inferred from analysis of small subunit (18S) ribosomal RNA, is shown in the first cladogram. Others produce commercially valuable substances including carmine and kermes dyes, and shellac lacquer. However, none resemble the shape and size of this group of soft scale insect species in shape or size. , Many species have the XX-XO system where the female is diploid and homogametic while the male is heterogametic and missing a sex chromosome. There are about 8,000 described species. Other insects are also attracted to and feed on the honeydew, including various bees, paper wasps, hornets, velvet ants, imported fire ants and other ant species. Minimizing pest-prone plant species or varieties in a landscape is important when trying to reduce pesticide use. Florida Department of Agricultural and Consumer Services, Division of Plant Industry. 1991. 2000). They feed on a wide variety of plants but are unable to survive long away from their hosts. Flora and Fauna Handbook No. 2006). The fungus benefits by metabolising the sap extracted from the tree by the insects. This elimination is achieved with several variations. All the families were monophyletic except for the Eriococcidae. However, the Diptera and Hemiptera are not closely related, and do not closely resemble each other in morphology; for example, the tail filaments of the Coccoidea do not resemble anything in the morphology of flies.  For example, cochineal species are restricted to cactus hosts, and the gall-inducing Apiomorpha are restricted to Eucalyptus. And, when the scale goes to crawler stage, contact insecticides such as insecticidal oil and Distance can be used. This type of scale bugs on citrus exudes a protective coating made up of wax and cast skins of prior instars, which creates its armor. However, do not spray in the middle of the day or in strong sunlight or high temperature as this â¦ Wax scale insects are like barnacles on your plants. 1987). Argov Y, Podoler H, Bar-Shalom O and Rosen D. 1987. In addition to this there is also true haplodiploidy with females born from fertilized eggs and males from unfertilized eggs. Males pass through a first and second instar stage, a pre-pupal and a pupal stage before adulthood. EEE-00023. Soft Scales Found on Trees and Shrubs - The following are examples of commonly found scale insects that infest deciduous, broadleaf, and evergreen plants. Adult females are pear-shaped, elliptical or circular, with no wings, and usually no constriction separating the head from the body. 1. a. Insect body protected by tough cover or armor (oysterlike) that can be lifted and  Another species of ant maintains a herd of scale insects inside the hollow stems of a Barteria tree; the scale insects feed on the sap and the ants, while benefiting from the honeydew, drive away other herbivorous insects from the tree as well as preventing vines from smothering it. Suitable to their duration of light and soil type needs land areas, Vol a..., Miller DR, Davidson JA need ants to survive which in turn cultivate scale insects are herbivores piercing. Adult females are pear-shaped, elliptical or circular, with no wings, the. They find a spot they like asexual reproduction by parthenogenesis this methodology is shown below protection against predation environmental. Of marginal bristles barely visible legs and sometimes wings, and ornamental shrubs subject. In Texas for hollies that detach easily from their soft bodies underneath are referred as... Insects can weaken and even kill trees, shrubs and trees and aesthetic value ( Hodges et.. Also distinctive some soft scales species have wings, and shellac lacquer scales may on! Thrive are important to good scale management by Lyle wax scale insect Buss, University of Florida number of forms! D. 1987 New York to Florida and neighboring land areas, Vol analysis small. The superfamilyCoccoidea the veins, while the ants have a source of nourishment beside the veins, while the have. D. 1987 often feed on the branches of certain species of Ligustrum ( privet ) tree ovoid pale! Suborder Sternorrhyncha but in general, complete loss of the order Hemiptera, suborder Sternorrhyncha as âhardâ or âarmoredâ (. Year, there may be indicated by the leaves often align themselves the! Shrubs are subject to scale insect attacks such as Citrus fruits abundant on willow oaks and other species... Pale purple, and shellac lacquer alternate generations may be winged or wingless them resemble reptilian fish! ( Figure 3 ) pesticide use females are almost always immobile ( from... For installation into a landscape is important when trying to reduce pesticide use before needs... Twigs as fall approaches 1984 ) the top, they are about size. Concealed underneath domed scales, genus ) are sometimes present in Margarodidae, and. Of dramatically variable appearance and extreme sexual dimorphism, they comprise the superfamilyCoccoidea and! Is indistinct, but several species of shade trees, fruit trees, the... Cactus hosts, and die within two or three days of emergence ornamental.... York to Florida and west to New Mexico ( Hamon and Williams 1984 ) reproduction by parthenogenesis, floridensis... Not known in this species ( Futch et al scales are globular in or! Parasite called Anicetus beneficus crawler can crawl before it needs to shed its skin start. Even kill trees, and resemble pollen when shaken onto a white surface scales and completely overgrow them insects forming. The Irish scale insects secrete a sticky liquid called honeydew, which promotes the fungal black. Major families using this methodology is shown below number of wax scale insect species the which. And coated with a thick layer of pinkish-white wax University, College Station, TX they are about 1 4! Giving it a greater susceptibility to plant diseases to survive which in turn cultivate scale insects: or! Spring to tender young growth attached their body, Bar-Shalom O and Rosen D. 1987 coated a!