Rhizoecus albidus Goux

MOGHADDAM, MASUMEH & WATSON, GILLIAN W., 2022, The Scale Insects Of Iran (Hemiptera: Coccomorpha) Part 2 The Mealybugs (Pseudococcidae And Rhizoecidae) And Putoidae, Zootaxa 5126 (1), pp. 1-169 : 139-142

Rhizoecus albidus Goux

( Fig. 64 , distribution map Fig. 71 E )

Rhizoecus (Pararhizoecus) albidus Goux, 1942: 40 . Rhizoecus uniporus Borchsenius & Tereznikova, 1959: 323 . Rhizoecus gentianae Panis, 1968: 550 .

Field characteristics: Found on roots, mostly on grasses. Live adult female elongate oval, up to 1.5 mm long, white.

Microscopic diagnosis: Body of slide-mounted adult female small, 1.2‒1.5 mm long elongate-oval. Posterior end of body rounded. Anal lobes poorly developed, each with 1 long ventral seta and 2 long dorsal setae, appearing as a group of 3. Antennae each with 6 segments, geniculate. Legs well developed, claws long and slender, with a pair of digitules as long as or slightly longer than claw, each with a very minute apical knob; tarsal digitules pointed at tip and shorter than claw. Circulus present within borders of abdominal segment IV, heavily sclerotized and elevated on a cone, with distal circular plate containing about 7 circular areas. Ostioles well developed.

Dorsum with numerous short pointed setae, forming distinct groups on thorax and head. Trilocular pores following general distribution of setae. Tritubular pores/cerores not numerous, rarely more than 3 on any segment of abdomen or thorax and sometimes only a single one on mid-line; tending to be scattered on head. Some very minute tubular ducts present on abdominal segments, these very simple and heavily sclerotized; some segments entirely without ducts, others with 6 at most.

Venter with a more-or-less quadrate sclerotized area (cephalic plate) just anterior to clypeus, containing 4 marginal setae; body setae short and slender. Trilocular pores sparse; setae and trilocular pores forming groups on thorax and head. Multilocular disc pores absent. Tritubular pores/cerores very few, a single marginal pore/cerore present on some posterior abdominal segments, occasionally with 1 on thorax and 1 between antennal bases. Small tubular ducts, similar to those on dorsum, numbering 2–6 on some posterior abdominal segments.

Distribution: Rhizoecus albidus has been recorded from 17 countries in the Palaearctic Region including Iran ( García Morales et al. 2016), where it has been collected in Esfahan, Markazi and Tehran provinces ( Moghaddam 2001, 2013b).

Host-plants: The species has been recorded on host-plants in 24 genera belonging to 10 families ( García Morales et al. 2016). In Iran, it has been found on the roots of Echeveria sp. (Crassulaceae) , Festuca arundinacea (Poaceae) and Gymnocalycium baldianium (Cactaceae) ( Moghaddam 2013b).

Economic importance: None in Iran, but elsewhere the species has been recorded causing extensive damage ( Williams 1962).

Natural enemies: None recorded in Iran.

Comments: The accompanying illustration is from Williams (1962), page 43, Fig. 14 , and is reproduced with permission of the Trustees of the Natural History Museum, London, U.K.

Family PUTOIDAE Tang

Phylogenetic analyses based on nucleotide sequence data have shown that the genus Puto does not belong to the Pseudococcidae ( Cook et al. 2002; Gullan & Cook 2007; Hardy et al. 2008; Choi & Lee 2022) but is a separate archaeococcoid family, Putoidae , as indicated by Williams et al. (2001). Its family status is strongly supported also by morphological features of the adult males ( Hodgson & Foldi 2006; Hodgson & Hardy 2013; Hodgson 2020).

Principle characters. Slide-mounted adult female with eye height usually as great as length of first antennal segment. Antennae usually each with 9 segments, rarely with 8; intersegmental sensilla present between antennal segments III–IV, IV–V and VI–VII, but never present between segments V–VI; each surface of trochanter with 2–5 (usually 3 or 4) campaniform sensilla. Claw usually with a pair of basal spurs in addition to a plantar denticle; claw digitules often capitate but tarsal digitules almost never capitate. Cerarii numbering at least 18 pairs, situated on sclerotised plates; if more pairs present, this increase is due to division of cerarii on certain segments. Long tubular ducts almost always present on frons, anterior to mouthparts. Multilocular disc pores present on venter; quinquelocular pores absent; trilocular pores usually of 3 sizes: ventral pores smallest, dorsal pores noticeably larger, and cerarian trilocular pores slightly larger than dorsal pores.

Comments: The only extant genus in the family Putoidae is Puto . The fossil genus Palaeotupo is based on an adult male and its placement in Putoidae is questionable ( Vea & Grimaldi 2015).

Genus PUTO Signoret

Putonia Signoret, 1875a: 341 . Type species: Putonia antennata Signoret. Macrocerococcus Leonardi, 1907: 151 .

Principal characters: As for the family, see above.

Comments: Worldwide, 47 species are included in Puto ( García Morales et al. 2016) ; one species is known from Iran ( Borchsenius 1949).

Figures

FIGURE 14. Adult female of Dysmicoccus brevipes (Cockerell). © Magnolia Press, www.mapress.com/j/zt, reproduced with the copyright holder’s permission.

FIGURE 64. Adult female of Rhizoecus albidus Goux. © Trustees of the Natural History Museum, London, U.K.

FIGURE 71. Maps of species distributions in Iran. A. Vryburgia amaryllidis (Bouché); B. Vryburgia succulentarum Williams; C. Rhizoecus albidus Goux; D. Puto superbus (Leonardi).