Description of a new coccid ( Hemiptera , Coccidae ) on avocado ( Persea americana Mill . ) from Colombia , South America

A new soft scale insect, Bombacoccus aguacatae Kondo, gen. n. and sp. n. (Hemiptera: Coccidae) collected on the branches and twigs of avocado, Persea americana Mill. (Lauraceae) in Colombia, is described and illustrated based on the adult female. An updated taxonomic key to closely related genera of the Toumeyella-group is provided.


Introduction
In the last 10 years, nineteen species of scale insects have been described for Colombia.Two of these species, Laurencella colombiana Foldi and Watson (2001) (Monophlebidae) and Akermes colombiensis Kondo and Williams (2004) (Coccidae) were reported on avocados.Laurencella colombiana is a giant monophlebid collected in the municipality of Villamaría, in the State of Caldas, Colombia, where it is regarded as a pest of avocado because it causes dieback of branches and a signifi cant reduction in produc-tivity and fruit quality (Foldi and Watson 2001).Akermes colombiensis is a polyphagous soft scale insect recorded on avocado (Lauraceae), guava (Myrtaceae), a shrub of the family Melastomataceae and Ocotea sp.(Lauraceae) in Valle del Cauca, Colombia (Kondo and Williams 2004).Th e avocado tree on which A. colombiensis was collected has been cut down, and this species has not been collected on avocados since (T.Kondo, personal observation).
On April 2007, an interesting soft scale insect that produces a cottony wax cover was reported in Anserma, Caldas, Colombia, on avocados (A.A. Ramos-Portilla, pers. comm.).Th e author was able to visit the farm where the insect was originally collected and obtained specimens of this coccid on April 2, 2009.During this visit, the author noted that the avocado trees were aff ected by sooty moulds which grew on the coccids' honeydew.After studying the microscopic features of this coccid, it was determined that it was a species new to science and belonged to the Toumeyella-group, a group currently included in the subfamily Myzolecaniinae (Kondo and Williams 2009).Th e new species does not fi t into any known genus, and thus a new genus is erected here in order to accommodate it.

Materials and methods
Specimens were slide mounted and examined under a compound microscope.Descriptions of the body shape of the adult female is described both as unmounted and as mounted on a microscope slide.Th e body length and width of the adult female was measured in millimeters (mm) as mounted on the slide; other measurements are in microns (μm).Length was measured from the farthest point of the head to the posterior end of the body; width was the greatest width.Description of the adult female of the new species is based on multiple slide-mounted specimens.Th e number of specimens measured for the description is represented as: n = number of specimens studied.Th e slide-mounting technique follows that of Williams and Granara de Willink (1992).Th e material studied is represented by the number of slides and the number of specimens on each slide, e.g., 1(2) means 1 slide with 2 adult specimens.Th e growth stage and sex of the specimen is listed only for non-adult females.Th e depository in parentheses is given for each lot of material studied (see abbreviation of depositories below).Each drawing is a generalization of several specimens and was made with the assistance of a camera lucida attached to a phase contrast compound microscope.An updated taxonomic key to the adult females of the coccid genera of Myzolecaniinae that occur in the New World was modifi ed from Kondo and Williams (2009).
Abbreviations for the depositories are as follows: Generic description, adult female.Body of adult female convex, young adult females covered by a cottony to powdery white wax; old specimens lacking wax.Dorsum.Derm membranous but becoming heavily sclerotized at maturity.Dorsal tubercles absent.Body setae sharply spinose, straight or with bent tips.Preopercular pores oval in shape, convex, present in a group anterior to anal plates and extending onto mid-dorsum.Simple pores present.Dorsal microducts present, with well-developed septa, and a long terminal fi lament, distributed evenly throughout dorsum.Anal plates with 5 or 6 apical setae, with about 4 subapical setae, 2 fringe and 12 hypopygial setae.Anal ring with 10 setae.In older specimens, a sclerotized area about half the width or less of the anal plates is formed around anal plates.Anal ring with 10 setae, translucent pores in 2 irregular rows.Margin.Marginal setae sharply spinose, straight or with bent tips.Stigmatic spines totaling 3; median spine often longest.Eyespots not detected.Venter.Ventral derm membranous.Ventral body setae sharply spinose, with 3 pairs of long prevulvar setae.Submarginal setae in one row, similar to rest of ventral body setae.Interantennal setae totaling 6. Antennae reduced, each 4-6 segmented.Mouthparts well developed; labium with 4 pairs of setae.Legs all reduced; prothoracic legs generally shortest.Tarsal digitules each pointed; claw digitules each knobbed; claw without a denticle.Spiracles large, posterior spiracle largest and larger than hind leg.Spiracular pores with 5 loculi; each pore band broad, reaching margins.Tubular ducts absent.Perivulvar pores with 5 loculi, present in a small group on each side of anal lobes present ventrad to anal plates.Ventral microducts abundant, scattered throughout venter.
Diagnosis.Bombacoccus gen.n. is closest to Akermes Cockerell but the two genera can be separated by the following combination of features (morphological features of Akermes in parentheses): (i) dorsum with a dense pattern of microducts (dorsum without a dense pattern of microducts); (ii) young insects in life covered by a white cottony or powdery wax (young insects in life not covered by a white cottony or powdery wax); and (iii) perivulvar pores mostly quinquelocular, with one central loculus (perivulvar pores variable, with 7 or 8 loculi, with 2 or 3 central loculi).Character states of Akermes taken from Granara de Willink (1999).
Etymology.Th e new genus Bombacoccus is formed by the combination of the Medieval Latin word "bombax" meaning cotton and the Latin word "coccus" meaning a berry, and commonly used as an ending of scale insect names.Description, adult female (measurements based on n=18).Insects in life.Dorsum of young adult females covered by a white cottony wax, with a broad marginal fringe of cottony wax.Th e cottony wax is gradually replaced by a powdery white wax in older specimens (Fig. 1A-E), and eventually the wax completely wears out.Insect after removal of wax, yellow-green to greenish brown in color, but older specimens becoming dark brown.
Biology.Th e insects were found on the tree branches and twigs of avocados of two varieties.Tiny parasitic wasps have been found to emerge from the body of old females and a species of syrphid fl y (Diptera: Syrphidae) larvae have been found feeding on the coccid nymphs (Fig. 1F).Insects were observed being tended by Pheidole ants (Fig. 1G).Sooty moulds regularly grow on their excreted honeydew covering the branches, leaves and fruit (Figs 1H and I).Notes.Bombacoccus aguacatae sp.n. is the only known soft scale insect (family Coccidae) in Colombia with a dorsum covered in a white cottony or powdery wax.Most soft scales of the Toumeyella-group are covered by a thin layer of wax; however, a few species in North America are also covered either by a cottony wax, e.g., Pseudophilippia quaintancii Cockerell which occurs in the eastern USA and is covered by a profusion of fl uff y, snow white wax (Hamon and Williams 1984); Neolecanium cornuparvum (Th ro), also occurring in the eastern USA, which ie usually covered in a white bloom or mealy wax (Hamon and Williams 1984); and one other species from Mexico, Neotoumeyella leucaenae (Cockerell) which has been reported to be somewhat covered with small patches of dull white waxy secretion (Cockerell 1903).Bombacoccus aguacatae can be easily separated from P. quaintancii by the following features (morphological features of P. quaintancii in parentheses): (i) preopercular pores present (absent); (ii) dorsal microducts not invaginated (invaginated); and (iii) stigmatic setae present (absent).Bombacoccus aguacatae resembles also N. cornuparvum and N. leucaenae, however, B. aguacatae can be easily separated from these two species by the presence of ventral tubular ducts in the perivulvar region of N. cornuparvum and N. leucaenae, whereas Bombacoccus aguacatae completely lacks ventral tubular ducts.

Figure 1 .Figure 2 .
Figure 1.Bombacoccus aguacatae Kondo, sp.n.A Young adult female B, C Older adult female with cottony wax D Older adult female with powdery wax E Old adult female beginning to lose its wax F Left.Old adult females.Right.Larva of a predatory syrphid fl y G Adult female being visited by Pheidole sp.ant H Sooty mould on an avocado fruit I Sooty mould on leaves of avocado plant.Photo 1.A by A.A. Ramos-Portilla; Photos 1.B-I by T. Kondo.