Host status of eucalypt species to Pratylenchus brachyurus and Meloidogyne incognita

Abstract

Plant parasitic nematodes are major threats to Brazilian and world agriculture. Among them, Pratylenchus brachyurus and Meloidogyne incognita stand out as major pests for several crops, including corn, cotton, soybean among others, which can be components of integrated crop-livestock-forestry systems (ICLFs). In this context, information about the host status of eucalypts (Corymbia spp. and Eucalyptus spp.) to plant parasitic nematodes becomes more relevant in Brazil, due to the use of eucalypts in ICLFs. If tree components used on this system increase the population density of P. brachyurus and M. incognita, it is possible that these pathogens could damage shorter-cycle crops. Since information about the host status of eucalypts to plant parasitic nematodes is scarce, this study evaluated the host status of some eucalypt species to P. brachyurus and M. incognita. Two greenhouse trials were done to evaluate the reproduction of P. brachyurus and one to M. incognita, using some of the most cultivated species and hybrids of eucalypts in Brazil. The population growth of P. brachyurus increased on Corymbia citriodora, Eucalyptus grandis, Eucalyptus dunnii × Eucalyptus urophylla, and E. grandis × E. urophylla after ~90 days of inoculation. Conversely, despite M. incognita reproducing well in the control plants, no individuals were recovered from C. citriodora, E. urophylla and E. grandis × E. urophylla, which were classified as resistant plants. Based on both obtained and available data, M. incognita poses no threat to eucalypt species today. However, P. brachyurus is suggested to be a threat to eucalypts.

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

“…In such areas, eucalypt seedlings can suffer greater damage from plant pathogens ( Naidoo et al, 2014 ). Fungi and bacteria are the main pathogens of eucalypts ( Paine et al, 2011 ), but nematodes are also an emerging concern as parasites of eucalypt trees ( Cruz et al, 2003 ) and seedlings ( Khan, 2012 ; Bellé et al, 2018 ; Silva et al, 2020 ; Souza and Inomoto, 2021 ).…”

“…Eucalyptus dunni Maiden, E. grandis Hill ex Maiden, C. citriodora Hook and the hybrid E. grandis × E. urophylla ST Blake have all been reported as resistant to M. javanica and M. incognita ( Almeida et al, 2012 ; Silva et al, 2020 ; Souza and Inomoto, 2021 ). Nonetheless, the genetic variability of RKN suggests that more eucalypts should be assessed for their resistance/susceptibility to a larger range of Meloidogyne species and populations.…”