Host-status and host-sensitivity of Cucumis africanus and Cucumis myriocarpus to Meloidogyne incognita race 2 under greenhouse conditions

Four economically important genera in the Cucurbitaceae family, namely Citrullus, Cucumis, Cucurbita and Langenaria, have no resistance to Meloidogyne species, which cause extensive crop losses. Certain wild, but economically unimportant genera in this family have the potential for use as seedling rootstocks in vegetable husbandry. Preliminary studies suggested that wild watermelon (Cucumis africanus) and wild cucumber (Cucumis myriocarpus) were compatible with selected nematode-susceptible watermelon (Citrullus lanatus) cultivars. Therefore, the host-status and host-sensitivity of C. africanus and C. myriocarpus to Meloidogyne incognita race 2 were investigated to determine if they had the potential to serve as seedling rootstocks in suppression of nematodes in watermelon husbandry. The eight nematode levels were arranged in a randomised complete block design with 5 replicates. Fifty-six days after inoculation, the reproductive factors of M. incognita race 2 on both plant species were less than one, whereas the two Cucumis species did not suffer any yield loss in response to nematode infection. Consequently, C. africanus and C. myriocarpus are resistant to M. incognita race 2 and could possibly serve as a seedling rootstock to C. lanatus cultivars in the management of population densities of this nematode race.