Host suitability of commercial peach and plum rootstocks to plant-parasitic nematodes
The objective of the study was to screen commercial peach and plum rootstocks for their host status against Meloidogyne javanica (root-knot nematode) and Criconemoides xenoplax (ring nematode). Cuttings/seedlings of commercial stone fruit rootstocks were rooted in black nursery bags. The plants were transplanted to 2,400 mL plastic pots filled with a mixture of steam sterilised sand and fine composted bark (1:2). Plants were inoculated with a pre-determined concentration of nematodes per pot and kept under glasshouse conditions at 25°C for a period of 6 months. Results indicate that the rootstock GF 677 was significantly more sensitive than Kakamas seedling to root-knot nematodes, but both rootstocks were more sensitive to root-knot nematodes than Marianna, Maridon, Flordaguard, 5A-5-34, 7B-25-21, Garnem and Viking (5A-5-34 and 7B-25-21: rootstocks bred in South Africa). Evaluation results in pots inoculated with ring nematodes indicated that all rootstocks used, sustained high numbers of ring nematodes. The rootstocks Marianna, Flordaguard, Atlas and Garnem had significantly higher numbers of ring nematodes than the other rootstocks used, except Guardian. The rootstocks GF 677, Maridon, 5A-5-34, 7B-25-21 and Viking were in the 50% range when Marianna was defined as 100%. To correlate these results with field data, soil samples were taken in a plum orchard (11 different stone fruit rootstocks available) during 2008 (after planting), 2012 and 2014. Rootstocks were planted in a randomised complete block designs with different rootstocks planted in blocks of three tree plots. During 2014, the ring nematode numbers in the root zone of Marianna was significantly higher than those in the root zone of other rootstocks. Ring numbers in the root zone of Viking and SAPO 778 clonal and seedling rootstocks never increased above the 500 ring nematodes 300 cm-3, the level described as damaging.
Stassen, P.J.C. and Malan, A.P. (2021). Host suitability of commercial peach and plum rootstocks to plant-parasitic nematodes. Acta Hortic. 1304, 315-320
Criconemoides xenoplax, Meloidogyne javanica, nematode inoculation, nematode evaluation, sugar flotation technique