LAUSR

The four major and globally widespread Meloidogyne spp., M. arenaria (Neal, 1889), M. hapla Chitwood, 1949, M. incognita (Kofoid & White, 1919) and M. javanica (Treub, 1885) (see Jones et al., 2013), are also abundant in South African crop production areas (Kleynhans et al., 1996). Many other species parasitise crops in South Africa, including M. enterolobii Yang & Eisenback, 1983 (see Kleynhans et al., 1996; Marais, 2014). Meloidogyne enterolobii, reported from only a few crop production areas in South Africa (Van den Berg et al., 2017), is very aggressive, has a wide host range and is known to overcome various root-knot nematode resistance genes (Castagnone-Sereno, 2012). As it is morphologically similar to M. incognita and other thermophilic species, it is prone to being misidentified (Adam et al., 2007; Karssen et al., 2013). Various authors have emphasised the limitations in using only morphological characteristics (particularly perineal pattern morphology) for accurate identification of Meloidogyne spp. (Karssen & Van Aelst, 2001; Carneiro et al., 2004; Hunt & Handoo, 2009), and as discriminating Meloidogyne spp. is crucial to optimise control strategies (Adam et al., 2007), the use of accurate isoenzyme and molecular deoxyribonuclease (DNA) methods became popular (Esbenshade & Triantaphyllou, 1985; Karssen et al., 2013). The sequencederived-amplified region (SCAR) polymerase chain reaction (PCR) technique has been proven to be a fast, reliable and accurate method to discriminate Meloidogyne spp. (Zijlstra et al., 2000). This study aims to update distribution knowledge by identifying Meloidogyne spp. from 28 populations isolated from diagnostic samples or experimental sites through the use of the SCAR-PCR technique and perineal-pattern morphology. Meloidogyne spp. eggs and second-stage juveniles (J2) were extracted from infected root samples of various crops cultivated in different crop production areas during the 2013-2014 summer-growing season (Table 1). Root samples (50 g) of each crop were subjected to the adapted NaOCl method (Riekert, 1995) for extraction of eggs and J2. The latter life stages of each of the 28 populations were inoculated on roots of individual rootknot nematode-susceptible tomato seedlings (‘Rodade’) grown in 5000 cm3 capacity pots containing Telone II (a.s. 1-3 dichloropropene; dosage of 150 l ha–1) fumigated sandy-loam soil (5.3% clay, 93.6% sand, 1.1% silt, 0.47% organic matter and pH (H2O) 7.47) in a glasshouse