The Brazilian mahogany tree, Swietenia macrophylla King (Meliaceae), is a native tree of Central and South American forests, where it also is known as Honduran or big-leaf mahogany, or simply mahogany (Snook 1998). It is a dominant species in the forest canopy, reaching a total height of about 70 m and a diam of about 3.5 m (Williams 1932; Lamb 1966; Pennington & Sarukhan 1968).

Mahogany wood is extremely valuable and used for many purposes (Lorenzi 1992). In Brazil, S. macrophylla has been widely used in urban forestation, especially in Brasília, Federal District, and in Manaus, Amazonas (Prance & Silva 1975). Its potential as a tree planted in parks and in agroforestry systems also has encouraged seedling production, which heretofore generally has been free of insects and diseases. So far, only 1 insect, the pyralid moth Hypsipyla grandella Zeller (Lepidoptera: Pyralidae), has been reported causing damage to this tree in Brazil.

Scale insects, including coccids (Hemiptera: Coccidae), are commonly associated with trees, sometimes causing severe damage. Coccid species of the genera Ceroplastes, Coccus, Eucalymnatus, Megalecanium, Pulvinaria, and Saissetia are abundant in Brazil, including many native species (García et al. 2017). This paper reports a coccid associated with S. macrophylla for the first time in Brazil, and includes observations on the morphology of the insect and associated species, and symptoms caused by feeding on mahogany seedlings.

Scale insects were collected on 1-yr-old mahogany plants cultivated in a glasshouse located in Brasilia, Brazil (15.7305°S, 47.8997°W). Scales were observed during Dec 2014 until Jan 2015 infesting the leaves and stems. All stages of development were present, as was abundant honeydew secretion (Fig. 1). Samples were stored in 75% ethanol and slide mounted according to the methodology described by Gullan (1984) and Ben-Dov and Hodgson (1997). The insects were identified mainly using the characteristics given by Williams and Kosztarab (1972), Williams and Watson (1990), and Granara de Willink (1999). Voucher specimens were deposited in the Reference Collection of Insects and Mites, CRIA, at the Department of Plant Protection of FCAV/UNESP.

The scale attacking S. macrophylla was identified as Saissetia miranda (Cockerell & Parrott) (Hemiptera: Coccidae), commonly called Mexican black scale, a polyphagous soft scale recorded here for the first time in Brazil. Mahogany seedlings showed deformation of the stem and the apical bud and the presence of sooty mold fungi due to the large amount of honeydew excreted by the insect (Fig. 1). Sooty mold blocks light, reducing photosynthesis and tree vigor.

Genus Saissetia includes 44 described species, with 13 species reported from Brazil (García et al. 2017). They occur mainly in Afrotropical and Neotropical regions (García et al. 2017). The most economically important species are S. coffeae (Walker) and S. oleae (Olivier), both causing injuries to several cultivated plant hosts, especially coffee and olives trees.

Mexican black scale has been reported on 26 genera and 58 species of plant hosts, and also collected on another species of the same genera, S. mahagoni (L.) (Nakahara & Miller 1981; García et al. 2017). Mexican black scale originally was described by Cockerell & Parrott from samples collected on Abutilon sp. (Malvaceae) in Vera Cruz, Mexico (Cockerell 1899) and named Lecanium oleae mirandum. Later it was recorded in several places around the world, mainly in Central and North America, South Asia, and several islands in the Australasian region. In South America it is known only from Argentina (Granara de Willink 1999; García et al. 2017).

Macroscopically, S. miranda is similar to S. oleae, becoming gray and black in mature specimens, and with all stages possessing raised areas forming an “H” dorsally. Mature specimens of S. coffeae, are easily separated from S. oleae and S. miranda because it is light brown in color, with a smooth and convex dorsum, and devoid of the “H” on adult females; the “H” is visible only on young specimens (Choi & Lee 2017). Mounted specimens can be differentiated by the characters given in Table 1.

Also sometimes associated with S. macrophylla around the world are 6 other species of coccoids: Hemilecanium imbricans (Green) (Hemiptera: Coccidae); Chrysomphalus dictyospermi (Morgan), Hemiberlesia cyanophylli (Signoret), Ischnaspis longirostris (Signoret) (Diaspididae); Crypticerya multicicatrices Kondo & Unruh (Monophlebidae); and Dysmicoccus nesophilus Williams & Watson (Pseudococcidae). Swietenia macrophylla was not known to be a suitable host of S. mi randa until now. Production of seedlings is indispensable for the introduction of this tree into new areas. However, S. miranda can affect the development of mahogany plants and thus reduce the supply of high-quality seedlings to plantations in the region.

Fig. 1.

Saissetia miranda (Hemiptera: Coccidae) on Swietenia macrophylla. (a) Immatures and adults infesting stem, petiole, and on leaves of mahogany seedlings conducted under greenhouse conditions. (b) Detail of the macroscopic characteristic of adult female, with “H” on dorsum. (c) Sooty mold fungi on leaves.

Table 1.

Differentiation between Saissetia miranda, Saissetia oleae, and Saissetia coffeae.