Heavy oystershell scale populations on limbs and twigs weaken trees, but this damage is seldom seen in commercial orchards. Crawlers may settle on bark or fruit. Oystershell scale infests apple and a large number of other fruit, shade and ornamental trees and shrubs. Oystershell scale is a hardshell scale, meaning that insects develop a hard, protective covering over themselves that is difficult to penetrate with insecticides. This pest only reproduces once per year, with the egg hatch occurring in early to mid June over an approximate ten day period. Several predators feed on the scales but are rarely able to control them. VI. Damage consists of small, dark brown scales cluster on bark or on fruit. Then, prune off any extensively damaged branches. When a soft body is beneatha cover, the plant is likely to have live armored scales. There are no eyes or legs and the short antennae have only a single segment. Larvae of several parasites attack the eggs, and some birds also feed on scales. Low Temperatures and the Natural Control of the Oystershell Scale, Lepidosaphes ulmi (L.) (Homoptera: Coccidae). They are brown oystershell scale and gray ostershell scale. Oystershell Scale Crawlers. Lepidosaphes ulmi also known as apple mussel scale or oystershell scale is a scale insect that is a pest of trees and woody plants. ), affects fruit in most apple-growing provinces and states in eastern North America. At this stage, the young crawlers are susceptible to insecticide applications. Evidence: Look for tiny brown to gray oystershell-shaped scales, usually densely packed, on the bark (a, b). Parent B, 1970. Check plants for live scale infestations. 1) belongs to a group of insects called the armored, ... form) and a brown form (also known as the apple form). The oystershell scale is a common insect pest in Iowa. Oystershell scale, as the name implies, looks like a miniature oyster encrusted on a small limb or twig. 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. Foliage Spray This pest can be controlled with delayed-dormant sprays of oil or oil with an organophosphate insecticide. 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. If you have a smaller tree, old scale and eggs can be scrubbed off by hand with a soft plastic dishwashing pad. 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. [1] They hatch in the spring at about the time the host plant's buds are bursting. Of the shrubs, lilac is perhaps most frequently infested. Oystershell scale is an armored scale (its covering is a hardened waxy material). It has the appearance of small clusters of oyster-shaped “shells” that cover bark on shrubs and trees. There are two commonly found races of oystershell scale in Illinois. They can survive temperatures as low as -32 °C. At this time oyster shell scale may be causing more damage than any other insect in the Calgary area. Generally, pesticides used in commercial orchards prevent the build-up of this pest. The Influence of Spray Programs on the Fauna of Apple Orchards in Nova Scotia. 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. Cotoneaster has been the hardest hit, but other plants are also susceptible -- apples, ash, aspens and others. The overwintered eggs hatch Then the insect develops a scale which is like an outer shell, which is usually Ask your local Extension office for … It occurs throughout the United States and is more common in northern states than southern states. The scale overwinters as eggs under the mother's covering. Apart from forest trees and ornamentals, the oystershell scale is a pest of apples, pears, plums, peaches, apricots, mulberries and currants. The male is much smaller and has wings. Do not spray oystershell or olive scales during the dormant season because susceptible stages of these species are not present during winter. The oystershell scale, Lepidosaphes malicola (Hem. Note on Aphytis proclia and Anabrolepis mayri (Hymenoptera:Chalcidoidea), parasites of the oystershell scale, Lepidosaphes ulmi (Homoptera:Coccidae). Eggs are elliptical, and young nymphs are very small, six-legged and white in … Annals of the Entomological Society of Quebec, 15(2):71-79. 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