The genus Calacarus is a distinctive group of mites, as the females usually have a purplish body and three or five longitudinal wax-bearing ridges on the opisthosoma (Lindquist et al., 1996;Anon., 2014). Wax may also occur on the dorsal shield, following the dorsal shield lines (Lindquist et al., 1996). The rostrum of the female is relatively large and curves downwards (Huang, 2014). The coverflap of the female mite is 32.2 to 36 µ wide and 19.8 to 21.3 µ long, with many faint, short lines (Huang, 2014).
C. carinatus causes a bronzing or purple discolouration of infested leaves (Mamikonyan, 1935;Anon., 2014). Infested leaves also have a ‘dusty’ appearance due to the cast skins of the mites and the residue of ‘mite wax’ on the leaf surface (Anon., 2014). The white skins and wax on the upper leaf surface can be seen using a hand lens (Anon., 2014). Leaves attacked by the mites turn completely brown and dry up, and defoliation occurs in heavy infestations (Shiao, 1976;Vazquez, 1991).
Related invasive species
- Calacarus carinatus
Related Farm Practice
- Light
- Defoliation
- Hosts
C. carinatus is a mite native to Asia. It is now also present in Africa, Europe, the USA and Australia. It usually attacks camellias and can reduce tea leaf production. In Kenya, C. carinatus has resulted in loss of capital due to the reduction in tea leaf production.
C. carinatus causes a bronzing or purple discolouration of infested leaves, hence the common name ‘rust mite’ (Mamikonyan, 1935;Anon., 2014). This is more apparent on the leaf margins (Shiao, 1976). Infested leaves also have a ‘dusty’ appearance due to the cast skins of the mites and the residue of ‘mite wax’ on the leaf surface (Anon., 2014). Leaves attacked by the mites turn completely brown and dry up, and defoliation occurs in heavy infestations (Shiao, 1976;Vazquez, 1991). The mites usually attack older leaves and show a preference for the upper surface, especially along the midrib and margins (Light, 1927).
C. carinatus usually attacks camellias, but has also been found attacking Spathiphyllum plants in Florida greenhouses (Anon., 2014). It is said to have an unusually wide host range compared to other members of the genus, apart from Calacarus citrifolii (Lindquist et al., 1996). In addition to attacking Camellia sinensis, it has also been reported from Camellia japonica and ‘two hosts in two other dicot families’ (Lindquist et al., 1996). Other hosts include: leaves of Viburnum opulus in California, USA;Capsicum annum in Mauritius (Moutia, 1958);and Camellia kissi and Camellia caudate in Assam, India (Das and Sengupta, 1962).