Valid Names Results

Unaspis yanonensis (Kuwana, 1923) (Diaspididae: Unaspis)

Nomenclatural History

Chionaspis citri; Kuwana 1907. misidentification (discovered by Kuwana1926, 43).
Prontaspis yanonensis Kuwana 1923b: 3-17. Type data: JAPAN: Kyushu, Ikiriki, near Nagasaki, on Citrus sp.. Syntypes, female, Type depository: Sapporo: Entomological Institute, Faculty of Agriculture, Hokkaido University, Japan; accepted valid name Illustr.
Unaspis yanonensis (Kuwana, 1923); Takahashi & Kanda 1939a: 187. change of combination
Unaspis janonensis (Kuwana, 1923); Ter-Grigorian 1969a: 25. misspelling of species epithet
Unaspis yannonensis (Kuwana, 1923); Chou 1982: 67. misspelling of species epithet
Unaspis yanonennis (Kuwana, 1923); Foldi & Germain 2018: 10. misspelling of species epithet

Common Names

arrow-head scale Borchs1966
arrowhead scale MillerDa1990
yanon scale Xie1998
yanone scale Clause1927 VelasqRi1969
escama de Yanon CoronaRuMo1997
cochenille asiatique des agrumes WatsonKo2022a
yanone-kaigaramushi WatsonKo2022a

Ecological Associates

Hosts:

Families: 3 | Genera: 3

Araliaceae

Panax | Suh2026

Rubiaceae

Damnacanthus | Wang1981TC

Rutaceae

Citrus | ArzoneAl1987 Kuwana1923b Muraka1970
Citrus aurantium | Muraka1970 | var. daidai (= Citrus natsudaidai)
Citrus japonica | Kuwana1923b Muraka1970 | (= Fortunella japonica)
Citrus junos | Suh2020
Citrus maxima | Muraka1970 | (= Citrus grandis)
Citrus medica | Muraka1970
Citrus reticulata | Muraka1970 TakahaTa1956 | (= Citrus deliciosa)
Citrus trifoliata | Kuwana1923b Muraka1970 Suh2020 | (= Poncirus trifoliata)
Citrus unshiu | Kuwana1923b Muraka1970 Suh2020 TakahaTa1956 | (= Citrus nobilis unshiu)
Citrus x natsudaidai | Suh2020

Foes:

Families: 9 | Genera: 28

Aphelinidae

Aphelinus | Fulmek1943
Aphytis | Chou1982
Aphytis aonidiae | Chou1982
Aphytis chrysomphali | Chou1982
Aphytis lingnanensis | TakagiRo1981
Aphytis melinus | BlackbMi1984a
Aphytis proclia | Chou1982
Aphytis unaspidis | GongChLi1999
Aphytis yanonensis | ArzoneAl1987 KreiteMaDi1998 Takagi1983c
Coccobius fulvus | ArzoneAl1987 KreiteMaDi1998 Tanaka1981 | (= Physcus fulvus)
Encarsia citrina | BenassPi1972 HuangPo1998 | (= Aspidiotiphagus citrinus)
Marietta carnesi | BlackbMi1984a

Chrysopidae

Chrysoperla carnea | BlackbMi1984a | (= Chrysopa carnea)
Mallada desjardinsi | GongChLi1999 Ishii1932a | (= Chrysopa boninensis)

Coccinellidae

Chilocorus | BlackbMi1984a RenGuXi1992
Chilocorus bipustulatus | BlackbMi1984a
Chilocorus renipustulatus | Chou1982 YangShGu1997 | (= Chilocorus kuwanae)
Chilocorus stigma | Benass1969
Cryptogonus orbiculus | BlackbMi1984a
Nephus phosphorus | BlackbMi1984a
Nephus ryuguus | BlackbMi1984a
Novius | BlackbMi1984a
Novius pumila | BlackbMi1984a | (= Rodolia pumila)
Platynaspis lewisii | Chou1982
Propylea japonica | BlackbMi1984a
Rhyzobius lophanthae | BlackbMi1984a | (= Lindorus lophanthae)
Sasajiscymnus hareja | BlackbMi1984a
Sasajiscymnus quinquepunctatus | BlackbMi1984a | var. okinawanus (= Pseudoscymnus quinquepunctatus okinawanus)
Scymnomorphus bicolor | BlackbMi1984a | (= Sukunahikona bicolor)
Scymnus | Chou1982 GongChLi1999
Scymnus dorcatomoides | BlackbMi1984a
Scymnus posticalis | AAEE1925 | (= Scymnus ishidai)
Stethorus japonica | BlackbMi1984a
Telsimia chujoi | BlackbMi1984a
Telsimia emarginata | HuangWaZh1983a
Telsimia nigra | BlackbMi1984a

Cybocephalidae

Cybocephalus gibbulus | BlackbMi1984a
Cybocephalus nipponicus | SongHuHu1990

Encyrtidae

Arrhenophagus chionaspidis | GongChLi1999
Coccidencyrtus longicaudatus | TanZh1998
Homalotylus albifrons | Fulmek1943 | (= Anisotylus albifrons)

Endomychidae

Saula japonica | BlackbMi1984a

Nectriaceae

Microcera | BlackbMi1984a
Microcera coccophila | BlackbMi1984a | (= Fusarium coccophilum)
Nectria coccophila | BlackbMi1984a | (= Sphaerostilbe coccophila

Stigmaeidae

Agistemus terminalis | BlackbMi1984a

Tubeufiaceae

Podonectria coccicola | BlackbMi1984a

Geographic Distribution

Countries: 21

Armenia | TerGri1969a

Australia | BlackbMi1984a

Burma (=Myanmar) | BlackbMi1984a

China

Anhui (=Anhwei) | Hua2000
Chongqing | WatsonKo2022a
Fujian (=Fukien) | ChenWo1936 GongChLi1999
Gansu (=Kansu) | Tao1999 Wu1935
Guangdong (=Kwangtung) | ChenWo1936
Guangxi (=Kwangsi) | Tao1999
Guizhou (=Kweichow) | Tao1999
Hebei (=Hopei) | Hua2000
Henan (=Honan) | Hua2000
Hubei (=Hupei) | ChenWo1936
Hunan | Wang1936
Jiangsu (=Kiangsu) | ChenWo1936
Jiangxi (=Kiangsi) | ChenWo1936 Tao1999
Nei Monggol (=Inner Mongolia) | Tao1999
Shaanxi (=Shensi) | Tao1999
Shanxi (=Shansi) | WatsonKo2022a
Sichuan (=Szechwan) | HuangWaZh1983a Tao1999
Xianggang (=Hong Kong) | BlackbMi1984a
Xizang (=Tibet) | Hua2000
Yunnan | Tao1999
Zhejiang (=Chekiang) | ChenWo1936 Hua2000

Corsica | CorreaPaDu2016

Fiji | BlackbMi1984a Lever1945

France | Benass1969 Foldi2001

India | BlackbMi1984a

Indonesia | BlackbMi1984a

Italy | ArzoneAl1987 PellizDa1997

Japan | Balach1954e Tao1999

Malaysia | BlackbMi1984a

North Korea | WatsonKo2022a

Pakistan | BlackbMi1984a

Philippines | BlackbMi1984a VelasqRi1969

Ryukyu Islands (=Nansei Shoto) | TakahaTa1956

South Korea | BlackbMi1984a ESKSAE1994

Spain | WatsonKo2022a

Taiwan | BlackbMi1984a

Thailand | BlackbMi1984a

Vietnam | BlackbMi1984a

Keys

DaoBeWa2023: pp.1024, 1027-1028 ( Adult (F) ) [Diaspididae on citrus in Indochina and southern China.]
NiuFe2019: pp.579 ( Adult (F) ) [Species of Unaspis]
Watson2015a: pp.437 ( Adult (F) ) [slide-mounted adult females of Unaspis]
Zeng2000: pp.51 ( Adult (F) ) [Key to Chinese species of Unaspis]
LiuWa1996: pp.43 ( Adult (F) ) [Unaspis species in China]
Danzig1993: pp.306 ( Adult (F) ) [Key to species of Unaspis]
Chen1983: pp.29 ( Adult (F) ) [Key to species of Unaspis]
Chou1982: pp.67 ( Adult (F) ) [Key to Chinese species of Unaspis]
Takagi1961: pp.16 ( Adult (F) ) [Key to Japanese species of Unaspis]
Balach1954e: pp.289 ( Adult (F) ) [Key to species of Unaspis]
Rao1949: pp.65 ( Adult (F) ) [Key to species of Unaspis]
Kuwana1926: pp.41 ( Adult (F) ) [Key to species of Prontaspis] Key as: Prontaspis yanonensis

Remarks

Systematics: Unaspis yanonensis is similar to U. citri, but can be distinguished from it by having 48-64 macroducts on each side of the pygidium, 1 gland spine between the pygidial lobes, strongly diverging median lobes and 51-79 gland spines on each side of the body anterior of segment 4. U. citri has 18-35 macroducts on each side of the pygidium, 2 gland spines between the 2nd and 3rd lobes and between the 3rd and 4th lobes, slightly diverging median lobes and 27-39 gland spines on each side of the body anterior of segment 4 (Blackburn & Miller, 1984a).
Structure: Female scale 2.5-3.6 mm long, oyster-shell shaped, wax blackish brown, margin paler, dorsomedial longitudinal ridge wrinkled on sides. Exuviae terminal, brownish yellow. Male scale elongate, 1.3-1.6 mm long, felted, white, 2 or 3 longitudinal ridges. 1st exuviae brownish yellow, situated at anterior end of cover. Adult female body elongate, pygidium with 3 pairs of definite lobes, 4th lobes weakly indicated. Median lobes with conspicuous, paraphysislike sclerotization or yoke, median margins diverging apically and with conspicuous notches, medial margin noticeably longer than lateral margin. 2nd lobes bilobed, slightly smaller than median lobes, protruding beyond apex of median lobes, without notches. 3rd lobes bilobed, without notches. 4th lobes inconspicuous, simple or bilobed, represented by low series of notches (Blackburn & Miller, 1984a).
Biology: The overwintering population of Unaspis yanonensis consists of 2nd instar larvae and full grown male larvae and juvenile and mature female adults. In early May the 1st brood begins to hatch (Ohgushi & Miyasita, 1963). Unaspis yanonensis typically has between two and four generations annually in China, Japan, and the Mediterranean region. In Korea, the overwintered females start to produce their progenies (first generation) in mid-May. New female adults of the first generation start appearing in late June and peak in mid-July. The second generation female adults, occur starting in mid-September, and gradually increase in number until late October. (Kim, et al., 2010)
Economic Importance: Miller & Davidson (1990) list this insect as a serious and widespread pest. It is a very destructive pest of Citrus spp. in Japan (Watanabe, 1958). Huang & Zhang (1990) found that "machine oil emulsions" controlled 77 to 94% of immatures and adult females. Sprays of petroleum spay oil and lime sulfur were most effective against first and second instar nymphs, but later stage nymphs tended to produce abnormal scale covers which left them more open to attack by predators. (Kim, Seo and Choi, 2010) Two and three peak models have been developed by Kim, et al., 2010, to predict crawler occurrence in citrus orchards.
General Remarks: Detailed descriptions and illustrations by Kuwana (1926) and Blackburn & Miller (1984a). Color photograph in Watson & Kondo (2022a). Schutze et al. (2026) consider this species absent in Australia due to dubious records.

Illustrations

Citations

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Ali1969: distribution, host, taxonomy, 82-83
AlvareLiLu2020: phylogeny, 5
ArzoneAl1987: biological control, chemical control, distribution, economic importance, host, 533-538
Balach1954e: biological control, description, distribution, host, illustration, taxonomy, 289, 293-195
Balach1957: taxonomy, 33
Balduf1939: biological control, distribution, 283
BatcheWe1948: distribution, economic importance, host, life history, taxonomy, 717
BazaroSh1970: distribution, taxonomy, 109
Benass1969: distribution, economic importance, host, 793, 794
Benass1977: biological control, ecology, economic importance, 1
BenassBi1967: distribution, economic importance, host, 248-250
BenassPi1972: biological control, description, distribution, economic importance, host, illustration, life history, taxonomy, 187-212
BenassViRo1979: distribution, host, taxonomy, 284
BiHuWa2022: natural enemies, 14, 17
BlackbMi1984a: biological control, description, distribution, economic importance, host, illustration, taxonomy, 1-14
Borchs1937a: description, distribution, host, taxonomy, 116, 117
Borchs1949d: distribution, host, taxonomy, 218
Borchs1950b: distribution, host, 197
CaiLuWe2001: chemical control, 28
CaveRe1996: distribution, economic importance, host, 9, 14, 15, 18
Chen1936: distribution, host, taxonomy, 210, 228
Chen1983: description, distribution, host, illustration, taxonomy, 29, 32-33, 121
ChenWo1936: distribution, host, 104
Cheo1935: distribution, host, 102
Chiu1979: distribution, 527
Chou1982: biological control, description, distribution, host, taxonomy, 67-70
Chou1986: illustration, 466
Clause1927: distribution, economic importance, host, 4
Clause1933: distribution, host, 16, 26
Clause1978: biological control, distribution, economic importance, host, 288
CommeaSo1964: distribution, host, 49-50
CoronaRuMo1997: distribution, economic importance, host, 40
CorreaPaDu2016: biological control, distribution, economic importance, natural enemies, 640
CorreaPaDu2016: biological control, distribution, economic importance, natural enemies, 640
Danzig1972: distribution, taxonomy, 221
Danzig1993: description, distribution, host, illustration, taxonomy, 306, 310-311
DanzigPe1998: catalog, distribution, host, taxonomy, 368-369
DaoBeWa2018: distribution, morphology, phylogeny, 82
DaoBeWa2023: key, 1029
DarvasAbCa1994: chemical control, 53
DeBachRo1982: biological control, host, 626
DengZhMa2026a: molecular biology, 49
ESKSAE1994: distribution, list, 114
Ebelin1959: distribution, economic importance, host, 235, 280
Ferris1937: taxonomy, SI-130
Fleury1934: distribution, host, 493
Fleury1935: distribution, host, 517
Foldi1982: structure, 318
Foldi1983b: structure, 340, 341, 345
Foldi2001: distribution, economic importance, 306, 308
FoldiGe2018: distribution, 10
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GaoTu2024: behavior, chemical control, control,
Germai2008: distribution, 77-87
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GongChLi1999: biological control, distribution, host, 95-99
Guo1992: taxonomy, 2
HashimMiKo1985: biological control, distribution, host, 204-205
HashimMiMi1987: biological control, distribution, host, 189-191
HertinSi1972: biological control, 191
HodekHo2009: biological control, 235
Hoffma1927: distribution, host, 76
HuHeWa1992: distribution, illustration, 203
Hua2000: distribution, host, 162
HuangPo1998: biological control, 1859
HuangWaZh1983a: biological control, distribution, host, life history, 640-643
HuangZh1990: chemical control, 9-10
Ishii1932a: biological control, 195
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Kaneko2025: distribution, host, natural enemies, 8
Kawai1972: distribution, host, taxonomy, 43-44
Kawai1980: distribution, host, taxonomy, 270
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KimKi2013: chemical control, economic importance, life history, 60-63
KimLe2015: ecology, life cycle, reproduction, 787–795
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KozarWa1985: catalog, distribution, 88
KreiteAuGe2006: distribution, economic importance, host, 143
KreiteMaDi1998: biological control, distribution, host, illustration, taxonomy, 32-33
Kuhmin1970: distribution, economic importance, host, 93
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Kuwana1926: description, distribution, host, illustration, taxonomy, 41-43
LeeLeSe2024: natural enemies, 3, 7
Lesche2000: biological control, 919
Lever1945: distribution, host, 43
LitBa2014: distribution, 1
LiuChCh2020: DNA sequencing,
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LiuWa1996: key,
LongoMaPe1999a: distribution, 149
Luck1981: biological control, distribution, host, 174
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MatsumItNi2002: ecology, 83
MillerDa1990: economic importance, taxonomy, 305
MiyajiHa1987: biological control, distribution, host, 192-194
Muraka1970: distribution, host, 96
Nakao1962: biological control, 197
NakataSuTa2000: biological control, distribution, host, 21-25
Nishid2002: catalog, 143
NiuFe2019: description, diagnosis, distribution, 574
Noguch1932:
NoharaNaNa2000: chemical control, distribution, host, 271-281
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OhgushMi1963: distribution, host, life history, 291-299
OhgushMoIt1964: description, life history, taxonomy, 24-25
OhkuboYoNa1986: biological control, distribution, host, 194-199
Paik1958: distribution, host, 32
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Schmid1940: distribution, host, 273
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Tachik1959c: biological control, natural enemies,
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Takagi1983b: biological control, distribution, 93
Takagi1983c: biological control, distribution, host, 153
Takagi1991: biological control, distribution, 505
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TakagiRo1981: biological control, distribution, 318
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TamakiKa1969: structure, 80
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Tanaka1981: biological control, distribution, economic importance, host, 165-166
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Tanaka1981b: chemical control, taxonomy, 93-100
Tang1977: description, distribution, host, illustration, taxonomy, 182
Tang1984b: host, 130
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TerGri1969a: distribution, host, taxonomy, 25
Tikhon1966: distribution, host, 102
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