Aspidiotus aurantii Maskell 1879: 199.

Aonidia gennadii Targioni Tozzetti 1881: 151.

Aspidiotus citri Comstock 1881a: 8.

Aspidiotus coccineus Gennadius 1881: 189.

Aonidiella aurantii (Maskell); Berlese 1895: 125.

Chrysomphalus (Aonidiella) aurantii (Maskell); Cockerell 1899a: 396.

Chrysomphalus citri (Comstock); Lindinger 1935: 132.

Aonidiella coccineus (Gennadius); McKenzie 1939: 54.

Aonidiella gennadi (Targioni Tozzetti); McKenzie 1939: 54.

Chrysomphalus coccineus (Gennadius); Lindinger 1949: 211.

Field diagnosis. Adult female scale cover flattened and circular, reddish brown or reddish gray, about 1.5 mm in diameter (but according to Watson (2002) it can reach 2.0 mm), with dark central exuviae. Mature adult female kidney-shaped and sclerotized, white to slightly amber, about 0.8 mm in diameter (although according to Watson (2002) it can vary from 0.7 to 1.2 mm).

Discussion. Aonidiella aurantii usually can be differentiated from Ao. citrina (Coquillett) by the color of the scale cover, which is reddish-brown in Ao. aurantii, while Ao. citrina has a white to yellow scale cover. Morphologically, in slide mounts, Ao. aurantii has prevulvar scleroses and apophyses, whereas Ao. citrina lacks prevulvar scleroses, although it has prevulvar apophyses. Separation of these species can be difficult; according to Miller & Davidson (2005), additional characters that can be used are (characteristics of Ao. citrina in parenthesis): Ao. aurantii with plates with the fringing not very pronounced (fringing on posterior plates deeply pronounced); macroducts slightly shorter (macroducts slightly longer); and submarginal cluster of microducts on each side of segment IV numbering 8‒19, usually about 12 (numbering 4‒11, usually about 8).

Habits on the hosts. Aonidiella aurantii can be found on branches, also on leaves and fruits of citrus (González Hernández & Atkinson 1984). In this study it was found individually on avocado branches, where there were few live individuals; it was also found associated with other diaspidid scale species such as A. nerii, H. lataniae, H. rapax and D. near coccois.

Hosts. The scale is polyphagous, attacking members of 178 plant genera belonging to 77 families, many of which are economically important, such as mango, fig, blackberries, coconut, date palm, oil palm, banana, guava, agave, asparagus, cassava, papaya, peach, citrus, walnut, avocado, pomegranate, and grape, among others (Watson 2002; García Morales et al. 2016). In this study, Ao. aurantii was found associated with the avocado variety Mexicano 1.

Distribution. Aonidiella aurantii is present in 88 countries in Africa, America, Asia, Europe, and Oceania (Watson 2002; García Morales et al. 2016); in México it has been found associated with citrus fruits in the Tamaulipas (García Morales et al. 2016), State of México, Morelos and Sonora (González Hernández & Atkinson 1984). In our study it was recorded only in State of México: La Purificación orchard.

Natural enemies. Natural enemies reported for Ao. aurantii include members of 39 genera belonging to 14 families. Among the genera outstanding for the high number of species that attack the scale are those of parasitic wasps such as Aphytis and Encarsia (Aphelinidae), and Signiphora (Signiphoridae). Other important parasitoid wasp genera attacking Ao. aurantii scales include: Coccobius, Coccophagoides, Coccophagus, Marietta and Pteroptrix (Aphelinidae); and Adelencyrtus, Aphycus, Comperiella, Habrolepis, Pseudhomalopoda (Encyrtidae).

An important predatory genus outstanding for the high number of species that attack Ao. aurantii is Chilocorus (Coleoptera: Coccinellidae); other important predatory genera include: Coccidophilus, Cryptolaemus, Exochomus, Halmus, Microweisea, Nephus, Orcus, Pentilia, Pharoscymnus, Rhyzobius, Scymnus and Telsimia (Coccinellidae); mites in Cocphyllobius and Neophyllobius (Camerobiidae), Hemisarcoptes (Hemisarcoptidae), and Amblyseius and Euseius (Phytoseiidae); gall midges in Cecidomyia and Lestodiplosis (Cecidomyiidae); lacewings in Chrysoperla (Chrysopidae); dustywings in Conwentzia and Heteroconis (Coniopterygidae); thrips in Aleurodothrips (Phlaeothripidae); and entomophagous fungi in Clonostachys (Hypocreales), Microcera (Nectriaceae) and Podonectria (Tubeufiaceae) (García Morales et al. 2016; Noyes 2019). In the present study, because of the low number of specimens collected, no natural enemies were obtained from Ao. aurantii.