(Bouché, 1833)
Diagnosis
Scale cover of adult female in life oval, convex, brown with submarginal exuviae AONLAUL1.jpg; scale cover mostly composed of exuviae of second instar, giving an impression of the adult female being pupillarial; but the posterior margin of the second instar exuviae is split open and a small amount of additional scale cover is secreted posteriorly. Scale cover of male similar to that of female but smaller and narrower (Ferris, 1938). AOLAL.jpg
Body of slide-mounted adult female elongate pyriform, membranous, without any sclerostisation of intersegmental folds; ducts 1-barred; antennae each with one seta; a few stigmatic pores present beside each anterior spiracle AOLAS.jpg . Pygidial lobes approximately triangular, plates absent AOLAP.jpg ; not on Gramineae. Second instar female with fringed plates and elongate, narrow lobes AOLA2I.jpg .
Host range
Aonidia lauri has been recorded on hosts from the plant family Lauraceae (Borchsenius, 1966), e.g. Laurus sp., Laurus nobilis.
Affected plant stages: vegetative growing, flowering and fruiting stages
Affected plant parts: on stems, branches and leaves AONLAUL1.jpg
Biology and ecology
Landi and del Bene, 1994, studied the biology of A. lauri on Laurus nobilis in the field in Florence, Italy. A. lauri was viviparous, overwintered at the second instar stage and had two generations per year. In the laboratory, the life cycle of females was completed in 145.7 days at 15°C (for 12 h) and 20°C (for 12 h), and in 193.2 days at 15°C, whereas the duration of the life cycle of males was 134.5 and 144.6 days, respectively. At 5° and 10°C, only the first larval instar developed. This species is known to have the Comstockiella chromosome system (Nur, 1990).
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.
Symptoms
Groups of A. lauri on the leaves of Laurus nobilis cause the development of chlorotic patches AONLAUL4.jpg and necrotic areas AONLAUL3.jpg , due to the toxicity of the saliva injected while feeding. Balachowsky, 1951, mentions that heavy infestations can cause drying of the branches in plants growing in dry conditions.
Economic impact
Danzig and Pellizzari, 1998, mention that this species is often a pest on Laurus nobilis. Foldi, 2001, lists this species as an occasional pest in France.
Detection and inspection methods
Examine the undersides of leaves of Laurus nobilis for dark brown, oval scale covers. Chlorotic and necrotic patches on the leaves may indicate the presence of these scale insects AONLAUL3.jpg .
Phytosanitary risk
Aonidia lauri is mentioned on quarantine lists (Burger and Ulenberg, 1990). There is considerable movement of fresh leaves of Laurus nobilis in trade between countries, with an attendant risk of transport of this insect.
Natural enemies
Parasitoids:
- Aphytis aonidiae, in Italy
- Encarsia citrina, in Italy
- Encarsia fasciata, in Italy
- Encarsia lounsburyi, in Italy
Distribution
See Aonidia lauri distribution.
Microscopic examination of slide-mounted adult females is required for authoritative identification to species.
Other species of Aonidia similar to A. lauri are not known on Lauraceae, but occur on Cupressaceae and Taxodiaceae; some workers place these species in the genus Cupressaspis.
Aonidia mediterranea Lindinger is known from Greece, Spain, Malta and North Africa on leaves and fruits of species of Callitris, Cupressus, Juniperus and Thuja (Zahradník, 1990; Amparo Blay Golcoechea, 1993); this species has broad, fringed plates on the pygidium, unlike A. lauri AOLAP.jpg .
Aonidia shastae Coleman (redwood scale) AOSHASL1.jpg is known from California and most of the western USA, where it is native (Gill, 1997) and feeds on leaves and fruits of species of Cupressus, Juniperus, Libocedrus and Sequoia (Zahradník, 1990). It generally resembles A. mediterranea but differs in having only one pair of pygidial lobes; in contrast, A. lauri has two pairs of lobes and no fringed marginal plates AOLAP.jpg .
Comments
Aonidia lauri probably originated in the Mediterranean region, and has been spread more widely by the transport and cultivation of infested plant material, especially Laurus nobilis. It occurs under glass only in the northern parts of its range (Danzig and Pellizzari, 1998). The species has not been recorded from Australia, or from the Pacific islands.
Europe
Cyprus: The Natural History Museum collection, London, UK
Former USSR: under glass (Nakahara, 1982)
Former Yugoslavia: present, no further details (Danzig and Pellizzari, 1998)
France: present, no further details (Foldi, 2001)
Germany: present, no further details (Danzig and Pellizzari, 1998)
Greece: present, no further details (Danzig and Pellizzari, 1998)
Hungary: present, no further details (Danzig and Pellizzari, 1998)
Italy: present, no further details (Longo et al., 1995; Danzig and Pellizzari, 1998)
Sardinia: present, no further details (Longo et al., 1995)
Sicily: present, no further details (Longo et al., 1995)
Malta: present, no further details (Danzig and Pellizzari, 1998)
Portugal: present, no further details (Danzig and Pellizzari, 1998)
Azores: present, no further details (Nakahara, 1982)
Madeira: present, no further details (Nakahara, 1982)
Spain: present in Almería, Gerona, Grenada, Madrid, Toledo and Valencia (Amparo Blay Golcoechea, 1993)
Canary Is: present, no further details (Amparo Blay Golcoechea, 1993)
Switzerland: presen (Kozár et al., 1994; Kozár and Hippe, 1996)
United Kingdom
England: restricted distribution, occasional (Malumphy, 1997)
Asia
Israel: present, no further details (Danzig and Pellizzari, 1998)
Near East: present, no further details (Nakahara, 1982)
Sri Lanka: The Natural History Museum collection, London, UK
Turkey: The Natural History Museum collection, London, UK
Africa
Algeria: present, no further details (Danzig and Pellizzari, 1998)
Cape Verde Is: present, no further details (Nakahara, 1982)
North Africa: present, no further details (Nakahara, 1982)
Western Hemisphere
North America: present, no further details (Danzig and Pellizzari, 1998)
USA
District of Colombia: present, no further details (Nakahara, 1982)
Mississippi: present, no further details (Nakahara, 1982)
New York: present, no further details (Nakahara, 1982)