Acanthococcus costatus Danzig

(Fig. 49, distribution map Fig. 88B)

Acanthococcus costatus Danzig, 1975: 43 . Eriococcus ulmi Tang, 1977: 45 .

Field characteristics: Body of live adult female oval, brown. Ovisac white with obvious transverse ribs and a depressed longitudinal zone along median body line (Danzig 1975).

Microscopic diagnosis: Slide-mounted body of adult female oval. Antennae each with 6 segments, with segment III obviously the longest. Frontal lobes present. Eyes situated on margins. Legs small; hind coxa and femur with spinulae on anterior surfaces; hind coxa without translucent pores; tarsus longer than tibia; each tibia with 4 elongate setae (median seta absent); tarsal and claw digitules all slightly knobbed, longer than claw; each claw with a denticle. Anal lobes heavily sclerotized, each lobe with numerous teeth on mesad margin, dorsum with 3 enlarged setae, venter with 3 slender hair-like setae and a suranal seta. Anal ring dorsal, complete, with 1 row of pores and bearing 8 setae. Cauda present.

Dorsum with enlarged setae normally of 3 sizes: each segment with 2 or 3 large setae along each margin, each seta less than 2x as long as a dorsal enlarged seta; additional large setae often forming 2 longitudinal bands in medial area (not illustrated); medial area of abdominal segment VIII without enlarged setae. Macrotubular ducts present throughout. Microtubular ducts numerous.

Venter with elongate hair-like setae; enlarged setae similar to smallest size on dorsum, present along body margin. Apical labial segment with 4 pairs of long setae and 1 pair of shorter apical setae. Quinquelocular pores numerous over entire venter. Macrotubular ducts of 2 sizes; (i) larger setae numerous along body margin; and (ii) smaller setae fewer, present in medial or sublateral areas. Microtubular ducts absent. Cruciform pores present along lateral margins.

Distribution: Acanthococcus costatus is a Palaearctic species; it has been recorded from China, Russia and other nearby countries including Iran, Kermanshah province (García Morales et al. 2016, Torabi et al. 2010).

Host-plants: The scale is oligophagous, having been recorded on two species in the genus Ulmus ( Ulmaceae) (García Morales et al. 2016), including in Iran (Torabi et al. 2010).

Economic importance: Not known as a pest in Iran.

Natural enemies: None recorded in Iran.