Oystershell Scale
Lepidosaphes ulmi
Classification
- Phylum: Arthropoda
- Subphylum: Hexapoda
- Class: Insecta
- Order: Hemiptera
- Suborder: Sternorrhyncha
- Superfamily: Coccoidea
- Family: Diaspididae
- Genus: Lepidosaphes
- Species: ulmi
Pronunciation
How to pronounce Lepidosaphes ulmi: /ˌlɛpɪdoʊˈsæfiːz ˈʌlmi/
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Summary
Lepidosaphes ulmi, known as oystershell scale or apple mussel scale, is an invasive scale insect that damages woody plants by sucking sap, leading to branch death or tree decline. They are widespread, feasting on many host plants, and are difficult to control due to their protective scales.
Physical Characteristics
Adult female oystershell scale is up to four millimetres long, elongated, tapering to a point at the posterior end, often slightly curved. The upper side is banded, brown, waxy scale, and the underside is cream coloured. No eyes or legs; short antennae have only a single segment. The mandibles are lengthened into a stylet adapted for sucking sap.
Identification Tips
Resembles an oyster or mussel shell due to its elongated, curved shape and banded, waxy appearance.
Habitat
Commonly found on the bark of trees and woody plants, especially in areas with suitable host plants.
Distribution
Widespread throughout the world and more abundant in northern states of the USA.
Diet
Sucks sap from over 150 species of host plants, including apples, pears, plums, peaches, apricots, mulberries, and several trees from various families.
Life Cycle
Eggs are laid under the female's scale in the early spring. They hatch and disperse as crawlers, seeking protected sites to settle. They undergo multiple molts, forming protective scales.
Reproduction
The female lays approximately 100 oval white eggs under her body, and then dies. Parthenogenetic and bisexual reproduction occurs within populations.
Predators
Controlled to some extent by parasitoids such as Aphytis mytilaspidis and natural predators like ladybirds, particularly Chilocorus bipustulatus.
Ecosystem Role
Acts as a pest to a wide variety of trees and woody plants, potentially leading to tree decline and death in heavy infestations.
Economic Impact
Known pest of valuable fruit trees and ornamental plants, contributing to agricultural losses.
Misconceptions
Often mistaken for benign surface features of trees rather than harmful pests.
Tags
- pest
- invasive species
- scale insect
- hemiptera