Comstock, 1881
Diagnosis
In life, scale cover of adult female 1.0-2.0 mm long, circular to oval, flat to slightly convex, translucent light tan or grey-brown, with slightly darker yellow-brown terminal exuviae with a longitudinal median stripe PAPERL2.jpg . Male scale cover elongate, 1.0 mm long, tan to light brown, with a yellow-brown terminal exuviae, often marked with a median greenish stripe PAPERL.jpg . Body of adult female purple (Gill, 1997).
Body of slide-mounted adult female membranous, pyriform to elongate pyriform, with two-bar ducts; fringed plates extending as far forward as abdominal segment 2; submarginal duct tubercles present on each side of the cephalothorax and the first abdominal segment; eyespot small, rounded and inconspicuous; and membranous derm pockets absent PAPERS.jpg . Pygidium with three pairs of rounded unilibulate lobes, fourth and fifth lobes present as sclerotized points; 3 plates present between lobes 3 and 4 on each side; and without any submedian macroducts within the frame formed by the perivulvar pores PAPERP1.jpg .
McKenzie, 1945, gives a detailed morphological description, illustrations and a key to the many species of Parlatoria.
Host range
Parlatoria pergandii is a polyphagous species that has been recorded from hosts belonging to 72 genera in 17 plant families (Davidson and Miller, 1990). Citrus species are favoured hosts. Hosts include species of: Aegle, Anthurium, Asparagus plumosus, Aucuba, Buxus, Callistemon, Camellia, Celtis, Cinnamomum, Citrus spp., Croton, Cymbidium, Elaeagnus, Euonymus, Eurya, Ficus, Garcinia, Inocarpus fagifer, Jasminum, Laurus, Limonium, Mahonia, Malus spp., Myrtus, Nerium, Osmanthus, Pandanus, Photinia, Prunus spp., Pyrenaria, Scrophulariaceae, Scolopia, Severinia, Thunbergia, Tournefortia argentea and Yucca.
Affected plant stages: vegetative growing, flowering, fruiting and post-harvest stages
Affected plant parts: whole plant, mainly on leaves, but sometimes also on bark, twigs and fruit PAPERL1.jpg
Biology and ecology
Reproduction is sexual. There are three or four generations per year in California and the southeast USA, with development time varying with climatic conditions (Kosztarab, 1996; Gill, 1997).
Parlatoria pergandii often occurs together with P. cinerea on Citrus (Williams and Watson, 1988). According to Bodenheimer, 1951a, Citrus trees over 10 years old are particularly prone to attack because P. pergandii has a decided shade preference. Branches and trunks are attacked first; fresh infestations then develop on the leaves and fruits. Most of the individuals found on the fruits are often in the inner, shady part of the canopy (Garrido Vivas and Ventura Rios, 1993).
First instar crawlers are the primary dispersal stage and move to new areas of the plant, or may be dispersed by wind or animal agency. Mortality due to abiotic factors is high at this stage. Dispersal of sessile adults and eggs occurs through human transport of infested plant material (Beardsley and Gonzalez, 1975; DeBach and Rosen, 1991; Dreistadt et al., 1994).
Symptoms
Parlatoria pergandii prefers Citrus trees over 10 years old. Heavy infestation causes distortion and shrivelling of shoots; yellowing, wilting and fall of leaves, which may reduce the photosynthetic area of the plants, leading to lower yield or even death (Beardsley and Gonzalez, 1975; Brooks and Knapp, 1983; DeBach and Rosen, 1991). On Citrus trees, heavy infestations of P. pergandii and P. cinerea caused gumming, flaking and cracking of the bark, killing branches and sometimes whole trees (Walker and Deitz, 1979), although P. pergandii was in a minority in these infestations. When orange fruits are infested with P. pergandii, green spotting of the rind occurs under the colonies.
Economic impact
This species is widely known as a pest of Citrus, and has been recorded as such in several countries in the South Pacific region (Williams and Watson, 1988). In the Cook Is, combined heavy infestation of Citrus by P. cinerea and P. pergandii was associated with gumming, flaking and splitting of the bark, causing dieback of whole branches and sometimes killing the tree (Walker and Deitz, 1979). Heavy infestation leads to distorted growth, discoloration of foliage and fruit spotting, wilting, leaf-fall, loss of yield and even host death. Since the 1970s, P. pergandii has become one of the main pests in all Citrus-producing areas in Spain (Garrido Vivas and Ventura Rios, 1993). Davidson and Lyon, 1987, reported that it was a pest of Citrus in the Gulf Coast states of the USA; Dekle, 1976, considered it to be a pest of Citrus in Florida, and Crouzel, 1973, listed it as a pest in Argentina. Gerson, 1977, reported the increasing importance of P. pergandii in Israel, which he attributed to the maturation of the Citrus groves. Danzig and Pellizzari, 1998, described this species as a pest in the Palaearctic region, and Foldi, 2001, listed it as an economically important pest in France. Parlatoria pergandii is a 'B'-rated pest in California (Gill, 1997). It is an occasional pest of ornamentals (Davidson and Lyon, 1987), in which damage to foliage is particularly important. In India, it has been recorded damaging mango (Chua and Wood, 1990).
Detection and inspection methods
Examine leaves, branches and fruits in the inner, shady part of the canopy for circular to oval, flat to slightly convex, translucent light tan or grey-brown scale covers, each with slightly darker yellow-brown terminal exuviae. The presence of scales may be greater on the midribs of leaves and in pits in the rinds of fruits PAPERL1.jpg .
Phytosanitary protection
Parlatoria pergandii is mentioned on quarantine lists (Burger and Ulenberg, 1990).
Natural enemies
Parasitoids:
- Aphytis hispanicus, attacking: eggs, nymphs, adults, in Italy; Spain; Israel; China; Mexico; USA, Texas; Caucasus; Ghana; Introduced: Cook Islands
- Aphytis melinus, attacking: eggs, nymphs, adults, in India, Pakistan. Introduced: USA (California), South Africa, Australia, Argentina, Chile, Cyprus, Israel, Italy, Morocco
- Encarsia citrina, attacking: nymphs, adults, in Japan, Ghana. Introduced to: USA; Australia; Mediterranean Basin; Turkey; Italy, Indonesia (Bali), Tahiti, Fiji, Cook Islands, Africa
- Encarsia inquirenda, in Israel
Predators:
- Aleurodothrips fasciapennis, attacking: eggs, nymphs, adults, in Indonesia; introduced to: Fiji
- Chilocorus bipustulatus, attacking: nymphs, adults, in Israel; Spain; Morocco; Greece
- Cybocephalus fodori in Greece
- Cybocephalus micans, in Israel
- Hemisarcoptes coccophagus, attacking all stages apart from eggs, widespread including Israel; Introduced: New Zealand
- Rhyzobius lophanthae in Greece
Distribution
See Parlatoria pergandii distribution.
Parlatoria pergandii may be found in association with P. cinerea. Microscopic examination of slide-mounted adult females is required for authoritative identification to species.
Parlatoria crypta McKenzie (P. morrisoni McKenzie is a synonym) PACRYPL1.jpg could be misidentified as P. pergandii, but differs in having 1 or 2 submedian macroducts on abdominal segment VI PACRYP2.jpg; these ducts are absent from the pygidium in P. pergandii PAPERP1.jpg. Parlatoria crypta is a highly polyphagous species known from Eritrea, Niger, Nigeria, Sudan, Iran, Iraq, Oman, Saudi Arabia, Yemen, Trucial States, India (Andhra Pradesh, Bihar, New Delhi, Karnataka, Lakshadweep Is, Punjab, Uttar Pradesh), Pakistan, Afghanistan and West Malaysia on twigs and leaves of species of Asparagus, Azadirachta, Bauhinia, Carissa, Cassia, Citrus, Clerodendrum, Cocos, Cordia, Cordylia, Diospyros, Ehretia, Eriobotrya, Euonymus, Ficus, Grewia, Hibiscus, Jasminum, Laurus, Mallotus, Malus, Mangifera, Melia, Morus, Musa, Nerium, Olea, Phoenix, Podocarpus, Rosa, Ziziphus and others (McKenzie, 1945; Seghatoleslami, 1977; Fowjhan and Kozár, 1994; Danzig and Pellizzari, 1998; The Natural History Museum collection, London, UK). It is one of the diaspidid scale insects found neem (Azadirachta indica) in Niger and Nigeria, although it is not thought to cause much damage (Boa, 1995); however, Fowjhan and Kozár, 1994, said it was important on apples in Afghanistan. Amin, 1986, described and illustrated the surface morphology of newly hatched nymphs of Parlatoria crypta using scanning electron microscopy. Habit sketch PACRYL.jpg Adult male winged (Ghauri, 1962).
Parlatoria pittospori Maskell (pittosporum scale, mauve pittosporum scale) is an Australian species that could be misidentified as P. pergandii, but differs in having submedian macroducts on abdominal segment VI; also similar-sized ducts present just on and just outside the anterior margin of the sclerotized pygidial shield. In contrast, P. pergandii lacks submedian macroducts on abdominal segment VI, and has only small ducts just anterior to the anterior margin of the sclerotized pygidial shield. Parlatoria pittospori is a highly polyphagous species known from Australia, New Zealand, South Africa and USA (California, San Diego County) (Charles and Henderson, submitted; Henderson, 2000; Gill, 1997; Nakahara, 1982; McKenzie, 1945). It feeds on leaves and small stems, and has been recorded as a minor pest of ornamentals in California, and on apples in New Zealand; it will attack conifers (Gill, 1997). Among its hosts are species of Abies, Acacia, Aloe, Banksia, Callistemon, cycad, Dracaena, Dryandra, Hakea, Haworthia, Leptospermum, Macrozamia, Malus, Petrophile, Phoenix, Pimelea, Pinus, Pittosporum, Podocarpus, Pyrus, Viburnum and Xanthorrhoea (Gill, 1997; McKenzie, 1945). In the grey or tan scale cover, the yellow second instar exuviae has a longitudinal, median green line or patch in both sexes. Parlatoria pittospori is a minor pest of ornamentals and a 'B'-rated pest in California, where it has only one generation per year (Gill, 1997). Colony PAPITL2.jpg ; male and female scale covers PAPITL1.jpg
Comments
The area of origin of Parlatoria pergandii is uncertain; it is now widely distributed throughout the tropical and subtropical areas of the world, especially in countries where Citrus is grown (Nakahara, 1982; Williams and Watson, 1988). In northern countries it is only found under glass (Danzig and Pellizzari, 1998). In spite of the record published by Danzig and Pellizzari, 1998, P. pergandii is not established in the United Kingdom (C.P. Malumphy, Central Science Laboratory, UK, pers. comm.).
Europe
Cyprus: present, no further details (CIE, 1964b)
Denmark: present, no further details (Tao, 1999)
Former Czechoslovakia: present, no further details (Danzig and Pellizzari, 1998)
Former USSR: present, no further details (Danzig and Pellizzari, 1998; Tao, 1999)
Caucasus: present, no further details (CIE, 1964b)
Georgia, Republic of: present, no further details (CIE, 1964b)
Former Yugoslavia: present, no further details (Danzig and Pellizzari, 1998)
France: present, no further details (Danzig and Pellizzari, 1998; Foldi, 2001)
Corsica: present, no further details (CIE, 1964b)
Germany: present, no further details (Danzig and Pellizzari, 1998)
Greece: present, no further details (CIE, 1964b)
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 (CIE, 1964b; Danzig and Pellizzari, 1998)
Portugal: present, no further details (Danzig and Pellizzari, 1998)
Spain: present in Alicante, Almería, Castellón, Córdoba, Gerona, Madrid, Murcia, Sevilla and Valencia (Amparo Blay Golcoechea, 1993)
Balearic Is: present (Amparo Blay Golcoechea, 1993)
Canary Is: present, no further details (Amparo Blay Golcoechea, 1993)
Switzerland: present, no further details (Kozár et al., 1994)
Asia
China
Beijing: present, no further details (Tao, 1999)
Fujian: present, no further details (CIE, 1964b; Tao, 1999)
Guangdong: present, no further details (Tao, 1999)
Guangxi: present, no further details (Tao, 1999)
Hong Kong: present, no further details (CIE, 1964b; Tao, 1999)
Hubei: present, no further details (CIE, 1964b; Tao, 1999)
Hunnan: present, no further details (CIE, 1964b; Tao, 1999)
Inner Mongolia: present, no further details (Tao, 1999)
Jiangsu: present, no further details (CIE, 1964b; Tao, 1999)
Jiangxi: present, no further details (CIE, 1964b)
Qinghai: present, no further details (Tao, 1999)
Shandong: present, no further details (CIE, 1964b; Tao, 1999)
Sichuan: present, no further details (Tao, 1999)
Xizang: present, no further details (Tao, 1999)
Yunnan: present, no further details (Tao, 1999)
Zhejiang: present, no further details (Tao, 1999)
India: present, no further details (Tao, 1999)
Bihar: present, no further details (CIE, 1964b)
Karnataka: The Natural History Museum collection, London, UK
Kerala: present, no further details (CIE, 1964b)
Rajasthan: present, no further details (CIE, 1964b)
Tamil Nadu: present, no further details (CIE, 1964b)
West Bengal: present, no further details (CIE, 1964b)
Indonesia
Irian Jaya: present, no further details (CIE, 1964b)
Java: present, no further details (CIE, 1964b)
Iran: present, no further details (Seghatoleslami, 1977; Abivardi, 2001)
Iraq: present, no further details (Tao, 1999)
Israel: present, no further details (Izraylevich et al., 1995)
Japan: present (Kawai, 1980)
Honshu: present, no further details (CIE, 1964b)
Kyushu: present, no further details (CIE, 1964b)
Shikoku: present, no further details (CIE, 1964b)
Korea: present, no further details (Danzig and Pellizzari, 1998)
Myanmar: present, no further details (CIE, 1964b)
Pakistan: present, no further details (CIE, 1964b)
Philippines: The Natural History Museum collection, London, UK
Saudi Arabia: present, no further details (Danzig and Pellizzari, 1998)
Singapore: The Natural History Museum collection, London, UK
Syria: present, no further details (CIE, 1964b; Danzig and Pellizzari, 1998)
Taiwan: present, no further details (CIE, 1964b)
Thailand: present, no further details (CIE, 1964b)
Turkey: present, no further details (CIE, 1964b; Danzig and Pellizzari, 1998)
Africa
Algeria: present, no further details (CIE, 1964b; Danzig and Pellizzari, 1998)
Cameroon: present, no further details (CIE, 1964b)
Egypt: present, no further details (CIE, 1964b; Danzig and Pellizzari, 1998)
Eritrea: The Natural History Museum collection, London, UK
Libya: present, no further details (CIE, 1964b; Danzig and Pellizzari, 1998)
Morocco: present, no further details (CIE, 1964b; Danzig and Pellizzari, 1998)
Nigeria: present, no further details (CIE, 1964b)
Senegal: present, no further details (CIE, 1964b)
Seychelles: present, no further details (CIE, 1964b)
Sierra Leone: present, no further details (CIE, 1964b)
Somalia: present, no further details (CIE, 1964b)
South Africa: present, no further details (CIE, 1964b)
Tanzania
Zanzibar: present, no further details (CIE, 1964b)
Togo: present, no further details (CIE, 1964b)
Tunisia: present, no further details (CIE, 1964b)
Western Hemisphere
Argentina
Buenos Aires: present, no further details (Claps et al., 2001a)
Entre Rios: present, no further details (Claps et al., 2001a)
Santa Fe: present, no further details (Claps et al., 2001a)
Tucumán: present, no further details (Claps and Terán, 2001; Claps et al., 2001a)
Bermuda: uncommon (Hodgson and Hilburn, 1991)
Brazil: from the North-East to el Sur (Claps et al., 2001a)
Bahia: present, no further details (Claps et al., 2001a)
Guanabara: present, no further details (Silva et al., 1968)
Minas Gerais: present, no further details (Claps et al., 2001a)
Rio de Janeiro: present, no further details (Claps et al., 2001a)
Rio Grande do Sul: present, no further details (Claps et al., 2001a)
Sao Paulo: present, no further details (Claps et al., 2001a)
Cayman Is: The Natural History Museum collection, London, UK
Colombia: present (Kondo, 2001)
Cuba: present, no further details (Schotman, 1989)
Dominica: present, no further details (CIE, 1964b)
Dominican Republic: present, no further details (Schotman, 1989)
El Salvador: present, no further details (CIE, 1964b)
Guatemala: present, no further details (CIE, 1964b)
Honduras: present, no further details (CIE, 1964b)
Jamaica: present, no further details (CIE, 1964b)
Mexico: present (Miller, 1996)
Montserrat: present, no further details (CIE, 1964b)
Nevis: The Natural History Museum collection, London, UK
Nicaragua: present, no further details (CIE, 1964b)
Peru: present, no further details (CIE, 1964b)
Puerto Rico: present, no further details (CIE, 1964b)
Saint Lucia: present, no further details (Schotman, 1989)
Trinidad: present, no further details (CIE, 1964b)
USA: under glass in colder areas (Nakahara, 1982)
Alabama: present, no further details (Nakahara, 1982)
California: a very restricted distribution in San Diego County (Gill, 1997)
Connecticut: present, no further details (Nakahara, 1982)
District of Colombia: present, no further details (Nakahara, 1982)
Florida: present, no further details (Nakahara, 1982; Danzig and Pellizzari, 1998)
Georgia: present, no further details (Nakahara, 1982)
Hawaii: present on Oahu (Heu, 2002)
Illinois: present, no further details (Nakahara, 1982)
Kansas: present, no further details (Nakahara, 1982)
Louisiana: present, no further details (Nakahara, 1982)
Maryland: present, no further details (Nakahara, 1982)
Missouri: present, no further details (Nakahara, 1982)
Mississippi: present, no further details (Nakahara, 1982)
New York: present, no further details (Nakahara, 1982)
Oklahoma: present, no further details (Nakahara, 1982)
Pennsylvania: present, no further details (Nakahara, 1982)
South Carolina: present, no further details (Nakahara, 1982)
Texas: present, no further details (Nakahara, 1982)
Virginia: present, no further details (Nakahara, 1982)
Oceania
Australia: present, no further details (CIE, 1964b; Tao, 1999)
New South Wales: present, no further details (CSIRO, 2001)
Queensland: present, no further details (CIE, 1964b; CSIRO, 2001)
Bonin Is: present (Beardsley, 1966)
Caroline Islands: present, no further details (CIE, 1964b)
Cook Is: present (Williams and Watson, 1988)
Niue: present, no further details (Williams and Watson, 1988)
Norfolk I.: present, no further details (Williams and Watson, 1988)
Pohnpei: present (Beardsley, 1966)
Truk Is: present (Beardsley, 1966)
Western Samoa: present (Williams and Watson, 1988)