The appearance of the scale covers of adult female and male L. malicola in life is very similar to that of L. ulmi (Danzig, 1993). On this basis, scale cover of adult female elongate, 1.0-3.5 mm long, mussel-shaped, convex and silvery grey or light brown initially but becoming purplish to coppery brown with age, sometimes banded; with yellow-brown exuviae at the narrow end. Scale cover of male, if present, light brown, smaller, slenderer and more parallel-sided than that of female, with yellow terminal exuviae.
Body of slide-mounted adult female elongate, more than 1.8x as long as wide, and membranous, with a rounded head; head without obvious lateral tubercles; eye not developed into a spur; lateral marginal spurs present on margins of prepygidial segments I, II, III and IV, each spur moderately sclerotized, containing the opening of (usually) 2 macroducts; abdominal segments III, IV, V and VI each with a dorsal, sclerotized submarginal boss on either side LEMALS.jpg . Pygidium with median lobes with a pair of gland spines between them, not yoked,and without club-shaped basal scleroses LEMALMG.jpg ; perivulvar pores present; with 6 marginal macroducts on each side of pygidium LEMALP.jpg .
Lepidosaphes malicola is a polyphagous species that has been recorded from hosts belonging to 12 plant families (Borchsenius, 1966); members of the Rosaceae are favoured hosts. Hosts include species of: Acer, Berberis, Betula, Catalpa, Cercis, Cornus, Elaeagnus, Euonymus, Fraxinus, Hippophae, Jasminum, Juglans, Ligustrum, Lonicera, Lycium, Malus, Mespilus, Populus, Prunus persica, Pyrus, Rhamnus, Ribes, Robinia, Rosa, Salix and Syringa.
Affected plant stages: vegetative growing, flowering, fruiting and post-harvest stages
Affected plant parts: mainly on trunk and branches, but sometimes also on the leaves and fruit
Biology and ecology
In Iran, each female produces 14-140 eggs (Abivardi, 2001); there are two generations per year on apple, and the species overwinters in the egg stage. In the former USSR, there are also two generations per year; the overwintering stage occurs on the bark, while the summer generation sometimes spreads to the leaves and fruit too (Danzig, 1993). Development takes 51-57 days in Armenia (Babayan and Oganesyan, 1979). Sevumyan and Aslanyan, 1988, remarked that damage to walnuts decreased with altitude in Armenia, perhaps suggesting that L. malicola may not thrive at higher altitudes.
Crawlers are the primary dispersal stage and move to new areas of the plant or are dispersed by wind or animal contact. Mortality due to abiotic factors is high in this stage. Dispersal of sessile adults and eggs occurs through human transport of infested plant material.
In the former USSR, heavy infestations cause death of branches or even entire trees; infestation of fruits causes red spoting (Danzig, 1993).
Abivardi, 2001, said that L. malicola is one of the most important and widespread apple pests in Iran. Danzig, 1993, regarded L. malicola as very damaging to apple in Armenia, and to Ribes and Salix in Tadjikistan. Danzig and Pellizzari, 1998, described the species as a pest in the Palaearctic region. The species is polyphagous, infesting all parts of apple, pear, peach, apricot, plum, cherry and many other fruit, walnuts and other trees and bushes (Babayan and Oganesyan, 1979).
Detection and inspection methods
Examine the trunk and branches of the hosts listed above, especially species of Rosaceae, for elongate, mussel-shaped, convex and silvery grey/ light brown or purplish to coppery brown scale covers, sometimes banded, with yellow-brown exuviae at the narrow end.
- Aphytis sp., in Iran
- Aphytis mytilaspidis, in Armenia
- Physcus testaceus, in Armenia, Iran
- Chilocorus bipustulatus, in Armenia, Iran
- Hemisarcoptes malus, in Armenia
- Scymnus sp., in Iran
See Lepidosaphes malicola distribution.
Microscopic examination of slide-mounted adult females is required for authoritative identification to species.
Lepidosaphes camelliae Hoke (camellia scale) LECAMS.jpg could be misidentified as L. malicola, but differs in having no sclerotized spurs on the margins of abdominal segments II-IV; usually 4 or 5 submarginal and submedian ducts on each side of segment VI; and the marginal and submarginal ducts are almost the same size LACAMP.jpg. In contrast, L. malicola possesses sclerotized spurs on the margins of abdominal segments II-IV; more than 20 submarginal to submedian ducts on each side of segment VI; and the submarginal ducts are much smaller than the marginal ducts LEMALP.jpg. Lepidosaphes camelliae is known from USA (Alabama, Arkansas, Connecticut, Delaware, Florida, Georgia, Louisiana, Massachusetts, Maryland, Missouri, Mississippi, North Carolina, New York, Oklahoma, Oregon, South Carolina, Texas and Virginia), Mexico, China (Guangdong, Hunnan) and Japan (Tao, 1999; Nakahara, 1982; Kawai, 1980) on leaf undersides of species of Camellia, Cleyera, Cupressus, Ilex, Ligustrum, Magnolia, Rhaphiolepis and Ternstroemia (Tao, 1999; Danzig and Pellizzari, 1998; Kosztarab, 1996; Miller, 1996; Nakahara, 1982). Lepidosaphes camelliae is occasionally a serious pest on camellia and holly in Florida (Dekle, 1976). Heavy infestations cause yellow and orange leaf discolouration and premature drop (Johnson and Lyon, 1991). This species has 4-5 generations per year in California, where it is considered to be a 'B'-rated pest on camellias, holly, cuttings and small plants (Gill, 1997). Scale cover of adult female mussel-shaped, slightly convex, light or dark brown, with yellow terminal exuviae; scale cover of male similar to that of female but smaller and narrower, with green-gold terminal exuviae (Davidson and Miller, 1990). Female scale cover LECAML1.jpg ; male and female scale covers LECAML2.jpg ; female scaleLECAML3.jpg ; habit sketch LECAML.jpg
Lepidosaphes conchiformis (Gmelin) (fig scale, red oystershell scale, virgule du figuier, cochinilla delgada-marrón de la higuera, conchuela de la higuera) LECONS.jpg is a species not featured in the picture key, which has some similarities with L. malicola. It differs from L. malicola in lacking the sclerotized marginal spurs between the lateral lobes of the free abdominal segments LECONP.jpg that are present in L. malicola LEMALP.jpg. Lepidosaphes conchiformis is a polyphagous species that originated in the Palaearctic; it is known from Belgium, Bulgaria, Cyprus, former Czechoslovakia, France (including Corsica), Germany, Greece, Hungary, Italy, Sicily, Sardinia, Poland, Romania, Spain (mainland and Balearic Is), Switzerland, former Yugoslavia, Turkey, former USSR (South European Territory, Ukraine, Transcaucasus, Middle Asia), Algeria, Egypt, Iran, Iraq, Israel, India (Assam, Tamil Nadu), Pakistan, China, Japan, North America (including California) and South America, on leaves and branches of woody hosts including species of Acer, Betula, Carpinus, Celtis, Corylus, Crataegus, Diospyros, Fagus, Ficus, Fraxinus, Juglans, Malus, Olea, Pistacia, Prunus, Pyrus, Syringa, Tilia, Ulmus and Zelkova (Kosztarab and Kozár, 1988; Zahradník, 1990a; Amparo Blay Golcoechea, 1993; Kozár et al., 1994; Longo et al., 1995; Gill, 1997; Danzig and Pellizzari, 1998; Foldi, 2001; Abivardi, 2001). Fig is the favoured host in California, and heavy infestations reduce the quality of the fruit due to discolouration and distortion (Gill, 1997). Lepidosaphes conchiformis is commonest on the periphery of forests, in towns (often in alleys and parks) (Zahradník, 1990a). Scale covers mussel-shaped; those formed on the leaves tend to be pale and sigmoid, whereas those formed on bark are brown and straight. Reproduction is sexual and there is one generation per year; each female produces 5-8 eggs in Poland (Komosinska, 1975), but an average of 26 each in Germany (Schmutterer, 1959). Habit sketch LECONL.jpg ; appearance in life LECONCL1.jpg , LECONCL2.jpg , LECONL0.jpg ; adult female scale cover LECONL2.jpg ; adult female scale covers LECONL3.jpg
Foldi, 2001, lists this species as an economically important pest in France. Abivardi, 2001, discusses the morphology, biology and natural enemies of L. conchaspiformis. This species has morphologically distinct leaf- and twig forms; the twig form has a dark brown female scale cover, whereas the in leaf form the scale cover is white; the exuviae are terminal. In both forms the male scale cover is elongate, light tan or white with terminal exuviae. In California there are 2-3 generations per year, and the insect overwinters as the twig form adult female (Gill, 1997). In Europe there are 1 or 2 generations per year, and the overwintering female (whose body is red-violet) lays about 25 eggs in spring (Zahradník, 1990a).
Lepidosaphes conchiformis LECONS.jpg can be distinguished from L. camelliae (above) because it lacks small macroducts anterior to the second lobe that are present in L. camelliae LACAMP.jpg.
Lepidosaphes pallida (Maskell) (Maskell scale) LEPALLL.jpg , LEPALLL1.jpg and L. pallidula (Williams) LEPALD~2.jpg are morphologically very similar species. They are currently the subject of research (D.J. Williams, D.R. Miller and R.C. Henderson, personal communications), so their respective distributions and host ranges are not precisely known at present. Both these species differ from L. malicola in having antennal setae more or less fused into a single, thick seta on each antenna; the submedian ducts on abdominal segment VI about half as wide as a marginal pygidial macroduct; a marginal spur on either side of each of abdominal segments II and III, each containing 1 duct opening; and in lacking dorsal submarginal bosses on abdominal segments III-VI. In contrast, L. malicola has 2 setae on each antenna, one sometimes with a forked tip; submedian ducts on segment VI each about one quarter as wide as a marginal pygidial duct; a marginal spur on either side of each of abdominal segments II and III, each containing 2 or 3 duct openings; and has dorsal submarginal bosses on abdominal segments III-VI LEMALS.jpg. Lepidosaphes pallida is a Holarctic species that feeds on conifers, sometimes damaging them LEPALLL2.jpg , and occurs in the USA, New Zealand (Charles and Henderson, submitted) and possibly some countries in the Far East (Japan? Kawai, 1980). It is a 'B'-rated pest in California, although it is uncertain whether it still occurs there (Gill, 1997). Lepidosaphes pallida (known as L. newsteadi) was a serious pest in Bermuda in the 1940s, when it killed 60% of the native Juniperus bermudiana forest and adversely affected the tourist business; however, it has since been displaced by Carulaspis minima and is now very uncommon (Hodgson and Hilburn, 1991). Lepidosaphes pallidula LEPALD~2.jpg is a tropical/subtropical species known from southern Asia and possibly elsewhere (Japan? Kawai, 1980); it feeds on many species of broad-leaved plants. Both the photographs used here are from Japan. Colony LEPALD~1.jpg
Lepidosaphes malicola is a temperate species, probably of Asian origin. It has not been recorded from Africa, the Western Hemisphere, Australia, or from the Pacific islands.
Bulgaria: present, no further details (Danzig, 1993; Danzig and Pellizzari, 1998)
Armenia: present, no further details (Danzig, 1993)
Azerbaijan: present, no further details (Danzig, 1993)
Georgia, Republic of: present, no further details (Danzig, 1993)
Kazakhstan: present, no further details (Danzig, 1993)
Kirgizistan: present, no further details (Danzig, 1993)
Middle Asia: present, no further details (Danzig and Pellizzari, 1998)
Tadjikistan: present, no further details (Danzig, 1993)
Transcaucasus: present, no further details (Danzig and Pellizzari, 1998)
Turkmenistan: present, no further details (Danzig, 1993)
Uzbekistan: present, no further details (Danzig, 1993)
China: present, no further details (Danzig and Pellizzari, 1998)
North China: present, no further details (Danzig, 1993)
Xingjiang: present, no further details (Tao, 1999)
Bihar: The Natural History Museum collection, London, UK
Jamu and Kashmir: The Natural History Museum collection, London, UK
Iran: widespread (Seghatoleslami, 1977; Danzig, 1993; Abivardi, 2001)
Israel: present, no further details (Danzig and Pellizzari, 1998)
Turkey: present, no further details (Uygun et al., 1998)