Meloidogyne spp. in Eucalypts - Reproduction and Damage to Seedling Growth

Eucalypts are cultivated worldwide, but little is known about their status as hosts of root-knot nematodes (RKN) (Meloidogyne spp.). Moreover, information is scarce regarding the nature of the damage caused by RKN to eucalypt seedlings and trees. To investigate these aspects, we separately inoculated Meloidogyne enterolobii, M. javanica and M. incognita in seedlings of the world's most cultivated eucalypts: Eucalyptus dunni, E. grandis, E. cloeziana, E. camaldulensis, E. saligna, Corymbia citriodora, and the hybrid E. grandis × E. urophylla. After six months of greenhouse cultivation, we assessed nematode reproduction and variables that expressed the seedlings' shoot and root growth. We observed a diverse pattern of host statuses to RKN among the eucalypts, and all three Meloidogyne species reduced (p < 0.05) the root system mass, volume and length of E. grandis, E. saligna and the hybrid E. grandis × E. urophylla. Our results reaffirm previous reports indicating that RKN can delay the growth of seedlings in nurseries, who should thus adopt appropriate sanitary measures to avoid RKN establishment and spread. Moreover, the damage caused by RKN to eucalypts after just six months of cultivation suggests that the growth of eucalypt trees may be affected over the course of several years of cultivation.