Meloidogyne javanica (Treub) (Javanese root-knot nematode)

This nematode reproduced successfully on four tested fiber cultivars in South Africa, but the percent population increase differed among the cultivars: increase was highest on ‘Kompolti’ and ‘Ferimon’, intermediate on ‘Felina 34’ and lowest on ‘Futura 75’ (Pofu et al., 2010). Root and shoot weights of all cultivars were unaffected by nematode infection. Pofu and Mashela (2014) found the rate at which M. javanica increased on hemp cultivars to vary markedly, with optimal numbers occurring on ‘Kompolti’, ‘Futura-75’ and ‘Ferimon’ at 56 days, while optimization on ‘Felina-34’ required 151 days. Unspecified varieties of C. sativa were hosts for M. javanica in India (Nirula and Kumar, 1964) and Iran (Esfahani and Ahmadi, 2010), and the nematode caused moderate galling on hemp growing as weeds in winter tomato fields in Pakistan (Ahmad et al., 2015). In Florida, six industrial hemp cultivars and landraces (‘Helena’, ‘Tygra’, ‘Fibranova’, ‘Eletta Campana’, ‘Carmagnola’, and ‘Carmagnola Selezionata’) were tested in the greenhouse for susceptibility to M. javanica (Coburn and Desaeger, 2019) . All six cultivars were excellent hosts, with Rfs of 34‒52, but plant biomass was not affected. Galls were non-coalesced, small, and numerous throughout the entire root system.