South Africa Wine Technical Yearbook 2025

TABLE 1. Host status of grapevine rootstocks. Rootstock M. javanica

M. incognita

C. xenoplax

X. index

P. vulnus

101-14 Mgt

MS MS

MR MR

S S S S S S S S S S S S S

S S

MR

143-B

S R R R S S

Couderc 3306 Couderc 3309 Dog Ridge Evex 13/5

S S R S S R S R R R R R R S S S

S S R S R S R R R R R R S R

MS MS

R S S R S S S S S S S S S S

Fercal

N/A

Freedom Gravesac Harmony

MR MR N/A N/A MS

N/A

Paulsen 1103 Paulsen 775

Ramper Ramsey

R

MS

MR

Richter 110 Richter 99 Ruggeri 140 Schwarzmann

MS

MS

S

S S S

MS

S

MR

MS MS

N/A

MS MR

SO4

N/A

US 8-7

S

S

S

* R = Resistant; MR = Moderately resistant; MS = Moderately susceptible; S = Susceptible. Results

the resistance of Couderc 3306, Couderc 3309, Dog Ridge, and Ramper to P. vulnus and other lesion nematode species. Although the XiRi locus, a gene for X. index resistance, was absent during molecular screening, Dog Ridge and Freedom showed moderate resistance to X. index, pending confirmation through further studies. Other rootstocks, like Fercal, seem to allow low levels of reproduction but exhibit higher numbers of root tip galls, making them to be considered as hypersensitive to X. index. None of the rootstocks were resistant to ring nematodes ( C. xenoplax ).

After two rounds of screening trials performed in different seasons, rootstocks Richter 99, Harmony, Ramper, Ramsey, Freedom and Dog Ridge showed resistance to both root knot nematode species (Table 1). Rootstocks 101-14 Mgt and 143-B had moderate resistance to M. incognita , while Schwarzmann showed moderate resistance to M. javanica . Although certain rootstocks did not support significant reproduction of P. vulnus, a future study explicitly aimed at root lesion nematodes in South African vineyards will confirm

Conclusion These trials have identified rootstocks with potential resistance to key nematode pests ( M. incognita, M. javanica, X. index and P. vulnus ). While some results are inconclusive and require further testing, several resistant rootstocks are already available in South Africa. These rootstocks enhance the resilience of grapevines, enabling them to thrive in challenging environments and reducing the need for chemical treatments. They also improve water and nutrient uptake, promoting healthy vine growth and consistent grape quality. By adapting to various soil types and conditions, resistant rootstocks ensure sustainable viticulture practices, supporting the long-term productivity and profitability of vineyards worldwide. These findings provide valuable guidance for nurseries and those implementing the Plant Improvement Scheme, helping to select rootstocks suited for specific challenges and conditions. Continued research will ensure the long-term value of these resistant rootstocks for the industry. 

Christopher Paulse inoculating potted rootstocks with nematodes.

Reference https://www.wineland.co.za/resistance-of-grapevine-rootstocks-to-nematodes-the-status-quo-in-south-africa/

For more information, contact Rinus Knoetze at knoetzer@arc.agric.za.

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TECHNICAL YEARBOOK 2025