Phenacoccus species

Zhao, Jing, Watson, Gillian W., Sun, Yang, Tan, Yongan, Xiao, Liubin & Bai, Lixin, 2014, Phenotypic variation and identification of Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) in China, Zootaxa 3802 (1), pp. 109-121 : 116-117

Key to Phenacoccus species in China (adult females)

1 (0) Feeding on grasses ( Poaceae )........................................................................... 19

- Feeding on other plants................................................................................ 2

2 (1) Feeding on Pinophyta ( Pinaceae and / or Taxaceae )......................................................... 25

- Feeding on other types of plants, not Pinophyta............................................................ 3

3 (2) Cerarii on body margins numbering 13–18 pairs............................................................ 4

- Cerarii on body margins numbering 1–12 pairs............................................................ 14

4 (3) Quinquelocular pores widespread on venter................................................................ 7

- Quinquelocular pores absent, or very few near mouthparts or coxae or singly on venter of thorax..................... 5

5 (4) Dorsal oral collar tubular ducts and dorsal multilocular disc pores present; circulus absent; feeding on roots................................................................................................... pumilus Kiritchenko

- Dorsal oral collar tubular ducts and dorsal multilocular disc pores absent; circulus present; mostly feeding on aerial parts of host-plants.......................................................................................... 6

6 (5) Ventral multilocular disc pores on midline of abdominal segment VII scattered between anterior and posterior margins of segment, or present in rows along both anterior and posterior edges of segment; specimens living in hot conditions may have a few translucent pores on apical end of hind femur; small cluster of ventral multilocular disc pores often present on submargin of some or all of abdominal segments VII-I; circulus medium-sized to quite large, transverse oval to somewhat anvil-shaped ( Fig. 5A ). Polyphagous, rarely found on Poaceae .............................................. solenopsis Tinsley (part)

- Ventral multilocular disc pores on midline of abdominal segment VII present in row along posterior edge only; specimens living in hot conditions lack translucent pores on apical end of hind femur, and lack small clusters of ventral multilocular disc pores on submargin of some or all of abdominal segments VII-I; circulus small to medium-sized, usually transverse oval ( Fig. 5B ). Polyphagous, rarely found on Poaceae .................................................. solani Ferris (part)

7 (4) Dorsal oral collar tubular ducts present at least on margins; on various host families................................. 8

- Dorsal oral collar tubular ducts absent; on Cynanchum spp. (Apocynaceae) ............................. atubulatus Wu

8 (7) At least a few dorsal multilocular disc pores present on abdomen, sometimes also on thorax......................... 9

- Dorsal multilocular disc pores absent..................................................................... 10

9 (8) Dorsal multilocular disc pores numerous in segmental rows across abdomen; some dorsal setae associated with trilocular pores; some dorsosubmedial cerarii present; polyphagous........................................ madeirensis Green

- Dorsal multilocular disc pores few, present singly on submargins of abdomen and occasionally on thorax; dorsal setae not associated with trilocular pores; dorsosubmedial cerarii absent; on Manihot esculenta and other broad-leafed hosts......................................................................................... manihoti Matile-Ferrero *

10 (8) Cerarii on margins numbering 13–16 pairs; cerarius present on midline of abdominal segment VII; circulus small; on Rehmannia (Scrophulariaceae) ................................................................... arctophilus (Wang)

- Cerarii on margins numbering 16–18 pairs; dorsosubmedial cerarii absent; circulus or circuli small to large; on various hosts. ................................................................................................... 11

11 (10) Dorsal oral collar tubular ducts confined to submargin or margin; circulus small; on Lantana camara and other broad-leafed plants, rarely on grasses.............................................................. parvus Morrison (part)*

- Dorsal oral collar tubular ducts present across entire width of segments, at least on thorax and anterior abdominal segments; on various hosts........................................................................................ 12

12 (11) Multilocular disc pores of 2 sizes; cerarii each containing 3–5 or more enlarged setae; circuli numbering 1–5 within a single population; on Fraxinus (Oleaceae) ............................................................. fraxinus Tang

- Multilocular disc pores of 1 size; cerarii each containing 2 (occasionally up to 4) enlarged setae; circuli numbering 1–5 in each species, but showing little variation within a single population; on various host families............................. 13

13 (12) Dorsal oral collar tubular ducts forming an irregular, single to double row across each segment; tubular ducts of 2 sizes present on both surfaces; with 1 circulus, situated on abdominal segment III.................... peruvianus Granara de Willink *

- Dorsal oral collar tubular ducts forming bands (each with more than 2 rows) across most segments; tubular ducts either all same size, or varying in size, not of 2 sizes only; circuli numbering 2–5 (occasionally 1), each situated on an intersegmental boundary..................... aceris (Signoret) (part) / perillustris Borchsenius / viburnae Kanda [See note below key].

14 (3) Dorsal oral collar tubular ducts present at least on abdomen; circulus usually absent; on various hosts.................. 15

- Dorsal oral collar tubular ducts absent; circulus present; on Asteraceae ............................... shanxiensis Wu

15 (14) Cerarii on margins numbering 6-11 pairs, with 4 pairs at anterior end of body and the rest on abdomen; most cerarii situated on an area of sclerotized cuticle; dorsal multilocular disc pores on abdomen few or absent; usually on steppe grasses rather than broad-leafed plants.................................................................. interruptus Green (part)

- Cerarii on margins numbering 1–10 pairs, with 0 or 1 pair present at anterior end of body and the rest on abdomen; cerarii each situated on cuticle that may or may not be sclerotized; dorsal multilocular disc pores always absent; hosts various........ 16

16 (15) Ventral quinquelocular pores numerous and widespread on thorax and anterior abdominal segments................... 17

- Ventral quinquelocular pores absent or localized around mouthparts, a few sometimes scattered singly on thorax......... 18

17 (16) Cerarii on margins numbering 1 pair on anal lobes, situated on sclerotized cuticle; anterior ostioles absent; on Salsola (Chenopodiaceae) ........................................................................... neimengulicus Wu

- Cerarii on margins numbering 2 or 3 pairs on apical abdominal segments, each situated on membranous cuticle; anterior ostioles present; on Chenopodiaceae .................................................. arthrophyti Archangelskaya *

18 (16) Cerarii on margins numbering 4 or 5 pairs (including 1 on head), all situated on membranous cuticle; oral collar tubular ducts numerous over entire dorsum; on herbaceous broad-leafed plants ( Brassicaceae , Fabaceae )...... ejinensis Tang in Tang & Li

- Cerarii on margins numbering 2 or 3 pairs, those on apical and penultimate segments each situated on sclerotized cuticle; usually feeds on grasses rather than broad-leafed plants.............................. phenacoccoides (Kiritchenko) (part)

19 (1) Multilocular disc pores present in a broad band around body margin; feeding on grasses, usually on roots..................................................................................................... poriferus Borchsenius

- Multilocular disc pores not forming a broad band around body margin; usually on aerial parts of host-plant............. 20

20 (19) Cerarii numbering 2 or 3 pairs, 2 situated on apical segments of abdomen and sometimes 1 on head; dorsal multilocular disc pores often present on apical segments of abdomen; usually feeds on grasses rather than broad-leafed plants...................................................................................... phenacoccoides (Kiritchenko) (part)

- Cerarii numbering 6 or more pairs; dorsal multilocular disc pores absent......................................... 21

21 (20) Quinquelocular pores present on venter................................................................... 22

- Quinquelocular pores absent............................................................................ 24

22 (21) Cerarii numbering fewer than 12 pairs; usually on grasses rather than broad-leafed plants.......... interruptus Green (part)

- Cerarii numbering 18 pairs............................................................................. 23

23 (22) Dorsal oral collar ducts confined to body submargin or margin; quinquelocular pores present in medial areas of venter; on Lantana camara and other broad-leafed plants, rarely on grasses................................. parvus Morrison (part)*

- Dorsal oral collar ducts forming segmental rows across entire width of thorax and abdomen, scattered on head; quinquelocular pores present only around mouthparts; hosts Poaceae ...................................... herbaceous Borchsenius

24 (21) Ventral multilocular disc pores on midline of abdominal segment VII scattered between anterior and posterior margins of segment, or present in rows along both anterior and posterior edges of segment; specimens living in hot conditions may have a few translucent pores on apical end of hind femur; small cluster of ventral multilocular disc pores often present on submargin of some or all of abdominal segments VII-I; circulus medium-sized to quite large, transverse oval to somewhat anvil-shaped ( Fig. 5A ). Polyphagous, rarely found on Poaceae .............................................. solenopsis Tinsley (part)

- Ventral multilocular disc pores on midline of abdominal segment VII present in row along posterior edge only; specimens living in hot conditions lack translucent pores on apical end of hind femur, and small clusters of ventral multilocular disc pores on submargin of some or all of abdominal segments VII-I; circulus small to medium-sized, usually transverse oval ( Fig. 5B ). Polyphagous, rarely found on Poaceae ..................................................... solani Ferris (part)

25 (2) Cerarii numbering 18 pairs; circuli usually numbering 2–5 (occasionally 1); on various hosts including Taxaceae ............................................................................................. aceris (Signoret) (part)

- Cerarii numbering 6 or 7 pairs; 1 circulus; hosts mainly Picea spp. ............................................. 26

26 (25) Multilocular disc pores present on dorsum in transverse rows; circulus small; on needles of Picea spp. and Taxus sp. in Europe (but not the Caucasus) and on Picea obovata in Siberia............................................. piceae (Löw) *

- Multilocular disc pores absent from dorsum; circulus large; on Picea schrenkiana in Tien Shan and Xingiang Uygur........................................................................................... borchsenii (Matesova)

Figures

FIGURE 5. Abdomens of slide-mounted adult females: (A) unpigmented Phenacoccus solenopsis from Guangxi, with anvilshaped circulus, multilocular disc pores over the entire depth of abdominal segment VII and in submarginal clusters on segments III–V (indicated by arrows); (B) P. solani from American Samoa, with transversely oval circulus, multilocular disc pores in a single row at the posterior edge of abdominal segment VII and no submarginal clusters on abdominal segments III-V. Photographs by G.W. Watson, California Department of Food & Agriculture.