It has the appearance of small clusters of oyster-shaped “shells” that cover bark on shrubs and trees. Inspect your red maple trees to determine what kind of scale insects you have by shaking the red maple tree’s branches over a sheet of paper and looking for scale insects. The male is much smaller and has wings. Pest description and damage The mature scale insect is approximately 0.125 inch long, hard-shelled, brownish or gray in color, and usually elongated and slightly curved like an oyster or mussel shell. Lepidosaphes ulmi also known as apple mussel scale or oystershell scale is a scale insect that is a pest of trees and woody plants. View Print Version. As scales mature, they are more difficult to kill because they form a protective covering. Despite its small size, the oystershell scale can inflict great damage on the trees and shrubs on which it lives. The oystershell scale, Lepidosaphes malicola (Hem. It can be found on a wide range of trees and shrubs. The Canadian Entomologist, Vol. The insect is most vulnerable in June when newly hatched young are crawling about. Chemical control of the oystershell scale, Lepidosaphes ulmi (L.), in apple orchards in southwestern Quebec. The oyster-shell or mussel scale (Lepidosaphes ulmi, L.) (fig. The list of PDFs below shows the suggested spray schedules for each tree crop. Note on Aphytis proclia and Anabrolepis mayri (Hymenoptera:Chalcidoidea), parasites of the oystershell scale, Lepidosaphes ulmi (Homoptera:Coccidae). Oystershell scale is a hardshell scale, meaning that insects develop a hard, protective covering over themselves that is difficult to penetrate with insecticides. The adult female oystershell scale is up to four millimetres long, elongated, tapering to a point at the posterior end and often slightly curved, somewhat resembling a mussel shell. The female dies after the last eggs are laid. Oystershell scales are difficult to target with insecticides, as they spend almost 75% of their lives as eggs protected by the scale. Often Confused With N/A. Hosts: Beech, birch, maple, ash, poplar, willow, elm, lilac, apple, pear, cherries and many other plants. There is also confusion as to the developmental ... of oystershell scale on fruit and nut trees. Generally, pesticides used in commercial orchards prevent the build-up of this pest. The female continues to grow in the same globular form and secretes a new, larger scale at each molt. Lepidosaphes ulmi also known as apple mussel scale or oystershell scale is a scale insect that is a pest of trees and woody plants.The small insects attach themselves to bark and cause injury by sucking the tree's sap; this metabolic drain on the plant may kill a branch or the entire tree. Over time, the scale ‘shells’ will reproduce and spread over large areas of the tree’s woody branches. Low Temperatures and the Natural Control of the Oystershell Scale, Lepidosaphes ulmi (L.) (Homoptera: Coccidae). Then, prune off any extensively damaged branches. Do not spray oystershell or olive scales during the dormant season because susceptible stages of these species are not present during winter. Oystershell scale, (Lepidosaphes ulmi), a species of insect in the armoured scale family, Diaspididae (order Homoptera), that is found on woody plants and secretes a hard, tough protective covering that resembles a miniature oystershell. Then the insect develops a scale which is like an outer shell, which is usually Parent B, 1973. Barkis usually intact beneath a scale. Elm scale, which is a soft scale insect, and Oystershell, which is a hard shelled variety can be treated quickly and effectively with natural treatments that promote regeneration of the tree, without harming surrounding shrubs and lawns. The Oystershell Scale insect has two stages, a crawler stage, which settles after a few days. The oystershell scale, Lepidosaphes malicola (Hem. Oystershell scale infests apple and a large number of other fruit, shade and ornamental trees and shrubs. The small insects attach themselves to bark and cause injury by sucking the tree's sap; this metabolic drain on the plant may kill a branch or the entire tree. There are no eyes or legs and the short antennae have only a single segment. The overwintered eggs hatch : Diaspididae), is a serious pest that injures fruits, shade trees, and shrubs, and is the most common pest of apple fruits. WA 38 First Commercial Season Storage & Packing Observations, WA 38 Optimization of Light Interception…, Pear Psylla Management using Reflective Plastic Mulch, Pear Psylla Insecticide Bioassay – Egg Mortality, Pear Psylla Management – Postharvest Sprays, Pear Psylla – Summer Generations Overview and Management, Management of Little Cherry & X-disease for Backyard Producers. The Influence of Spray Programs on the Fauna of Apple Orchards in Nova Scotia. 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. 1) is too well known to need any particular introduction ; suffice it to say that this insect has followed its principal food-plant, the apple tree, over the world.Though usually considered a serious pest in places in which it … Heavy infestations can kill branches and even cause trees to die. This scale insect, which is a bivoltine pest, overwinters as diapausing eggs beneath the protective, waxy cover of females. There is one generation of oystershell scale each season. Click on image for larger version Figure 2. Ask your local Extension office for … Oystershell scale is an introduced pest in Calgary. Oystershell scale is a very secretive little insect that usually goes unnoticed. In gardens, trunks and branches may be scrubbed and heavily infested wood pruned out and removed. Life History There are two races of the oystershell scale; the gray race which is found on lilac, ash, willow, poplar, and maple while the brown race is found on apple, dogwood, and poplar. There are two commonly found races of oystershell scale in Illinois. It infests trunks and branches but is not found on leaves. Refer to San Jose scale management. However, it thrives on neglected trees and has rarely been an orchard pest. It is of European origin but has been a common pest in the northwestern United States since 1850 and has since spread throughout the United States. Her scale darkens in colour and stays in place, protecting the eggs over the winter. The complete life cycle is described in this excellent bulletin from CSU. It is now a pest of all fruit trees and many ornamental and wild trees and shrubs throughout the U.S., particularly in hot, dry climates. Foliage Spray At this time oyster shell scale may be causing more damage than any other insect in the Calgary area. Crawlers may settle on bark or fruit. [1], Colorado State University Cooperative Extension Fact Sheet, https://en.wikipedia.org/w/index.php?title=Lepidosaphes_ulmi&oldid=900018908, Creative Commons Attribution-ShareAlike License, This page was last edited on 2 June 2019, at 22:41. Scale feeds by sucking the fluids of tissue underlying the bark. Some crawlers may develop into males. At this stage, the young crawlers are susceptible to insecticide applications. Its infestations are common in ornamental plantings where trees are subject to various stresses. by Stanley C. Hoyt, originally published 1993. Oystershell scale, as the name implies, looks like a miniature oyster encrusted on a small limb or twig. [2] The crawler moults twice before becoming an adult female, forming a protective scale from larval exuviae and secretions. Heavy oystershell scale populations on limbs and twigs weaken trees, but this damage is seldom seen in commercial orchards. The upper side is a banded, brown, waxy scale and the underside is cream coloured. 85, Issue. Parent B, 1970. Whenthe bump itself can be squashed it is likely to be some othertype of scale. The oystershell scale occurs generally throughout Canada and the United States. When this scale insect was first described in Europe in 1758, it was referred to as the mussel scale. Eggs are elliptical, and young nymphs are very small, six-legged and white in … They occur less frequently on the surface of leaves and fruit. The spray recommendations for home garden fruit trees have been updated for 2019. Oystershell scale feeding weakens the plant. They are brown oystershell scale and gray ostershell scale. The oystershell scale is a common insect pest in Iowa. After the second molt, the male develops wings. 1) belongs to a group of insects called the armored, ... form) and a brown form (also known as the apple form). Oystershell scale are found on trunks, branches, and twigs of many broad-leaved deciduous plants. It lives primarily on bark but can affect fruit also. The scale overwinters as eggs under the mother's covering. It resembles a San Jose scale crawler. There can be from 40 to 100 eggs under one scale.Crawlers emerge from the scale in May and June. The female lays about one hundred oval white eggs, retaining them under her body, and then dies. This pest only reproduces once per year, with the egg hatch occurring in early to mid June over an approximate ten day period. The scale insects resemble a small oyster shell and are usually in clusters all over the bark of branches on trees such as dogwood, elm, hickory, ash, poplar, apple etc. Annals of the Entomological Society of Quebec, 15(2):71-79. During heavy outbreaks plant death can occur. The female scale is shiny, light to dark grayish brown, with parallel ridges across, and is from 1/16 to 1/8 inch (1.5 to 3 mm) long. Lepidosaphes ulmi also known as apple mussel scale or oystershell scale is a scale insect that is a pest of trees and woody plants. This pest can be controlled with delayed-dormant sprays of oil or oil with an organophosphate insecticide. They then insert their long mouthparts into the host and secrete a waxy covering. When a soft body is beneatha cover, the plant is likely to have live armored scales. Use of horticultural oils may overcome this problem but control is still difficult. Oystershell scale, Lepidosaphes ulmi (Linn. Homoptera: Diaspididae. Flip over suspiciouslooking bumps on twigs and branches with a thumbnail. Oystershell scale is an armored scale (its covering is a hardened waxy material). These undergo four moults and the adult males have eyes, three pairs of legs, one pair of wings, a head and a body divided into a thorax and abdomen. They can survive temperatures as low as -32 °C. Oystershell scale (Lepidosaphes ulmi) San Jose scale (Quadraspidiotus perniciosus) Pest description and crop damage San Jose scale was introduced to the U.S. on flowering peach in the 1870s. The newly hatched crawler of either sex is pale yellow in color and has six legs. Oystershell Scale; May 10, 2000: Oystershell scale, Lepidosaphes ulmi, eggs are hatching throughout portions of Illinois. The adult scale resembles a miniature oyster shell. If you have a smaller tree, old scale and eggs can be scrubbed off by hand with a soft plastic dishwashing pad. When honeydew falls from a tree, leaves shouldbe inspected for live soft scales or mealybugs. Oystershell scale infests apple and a large number of other fruit, shade and ornamental trees and shrubs. Apart from forest trees and ornamentals, the oystershell scale is a pest of apples, pears, plums, peaches, apricots, mulberries and currants. This pest only reproduces once per year, with the egg hatch occurring in early to mid June over an approximate ten day period. This scale insect, which is a bivoltine pest, overwinters as diapausing eggs beneath the protective, waxy cover of females. : Diaspididae), is a serious pest that injures fruits, shade trees, and shrubs, and is the most common pest of apple fruits. This generally takes a combination of a few control methods. As eggs are laid, the body of the mother gradually shrinks into the smaller end of the scale and the eggs occupy the rest of the space. Some gardeners aren’t even aware the insects are present as they prune out dead branches the insects have killed. The insect overwinters as an egg under its mother's shell. Oystershell eggs typically hatch in late May or early June and the active ‘crawlers’ that emerge move about to find new sites to feed. The oystershell scale (Diaspididae Lepidosaphes ulmi) (Fig. The crawlers are tiny and disperse on the host, each one looking for a suitable protected site with thin bark in which to settle, remaining in that place permanently after sinking the stylet into the host plant's vascular tissues. Check plants for live scale infestations. Cotoneaster has been the hardest hit, but other plants are also susceptible -- apples, ash, aspens and others. But despite it’s tiny size, this insect can cause significant damage in trees or shrubs. Oystershell Scale A scale insect problem can be seen on trees in the form of small brown bumps, which look like small oyster shells attached to the branches and trunk of the tree. ), affects fruit in most apple-growing provinces and states in eastern North America. First, keep trees and shrubs well watered, feed and trimmed as scale tends to infest stressed or damaged trees first. It attacks many species of shade trees including apple, white ash, white elm, basswood, and red maple. [2] In some parts of the world, populations are controlled to a certain extent by the oystershell scale parasitoid, Aphytis mytilaspidis[3] and the ladybird Chilocorus bipustulatus. Oystershell scale . [1] They hatch in the spring at about the time the host plant's buds are bursting. [1], Over one hundred and fifty host plant species are known for the oystershell scale including members of the families Aceraceae, Betulaceae, Caprifoliaceae, Celastraceae, Elaeagnaceae, Grossulariaceae, Hydrangeaceae, Juglandaceae, Oleaceae, Pyrolaceae, Rosaceae, Salicaceae and Tiliaceae. The mandibles are lengthened into a stylet adapted for sucking sap. Biology Scales overwinter as fertilized females with 40-150 egg masses under their scale. They spend the winter as eggs under the hard waxy scale formed by the deceased female. Several predators feed on the scales but are rarely able to control them. Evidence: Look for tiny brown to gray oystershell-shaped scales, usually densely packed, on the bark (a, b). [1], The crawlers are vulnerable to a number of pesticides but adult oystershell scales are protected by their waxy scales which repel water. 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. Larvae of several parasites attack the eggs, and some birds also feed on scales. Not all colonies produce males and bisexual and parthenogenetic populations are known. The insect has one generation per year in the Northwest.It passes the winter in the egg stage under the scale of the mother. Description. The small insects attach themselves to bark and cause injury by sucking the tree's sap; this metabolic drain on the plant may kill a branch or the entire tree. Females never move again, but the males, which have wings, eventually emerge from their coverings and mate. It occurs throughout the United States and is more common in northern states than southern states. Damage consists of small, dark brown scales cluster on bark or on fruit. Females continue to grow in the same form and mature in August or September. 8, p. 282. Some races of oystershell scale have one generation per year, and others have two generations per year. Lepidosaphes ulmi. VI. Plant hosts include ash, lilac, willow, maple, apple, pear, plum, cotoneaster, linden, and viburnum. It has the appearance of small clusters of oyster-shaped “shells” that cover bark on shrubs and trees. Oystershell scale is a very common pest on aspen. http://www.ext.colostate.edu/pubs/insect/05513.html This key pest species usually infests lilac Syringa spp., ash, Fraxinus spp., dogwood, Cornus spp., maple, Acer spp., poplar, Populus spp., and willow, Salixspp., but it has been reported on more than 13… After a few days it sheds its skin and loses its legs and antennae, and begins to form the waxy scale coating. They can crawl some distance before settling down on the bark. 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