In response to growing concern about the spread of avocado sunblotch viroid (ASBVd), Du Roi Halls Nursery (DRHN) has reaffirmed its commitment to the highest standards of biosecurity and plant health assurance in avocado propagation. The nursery provides high-quality clonal plant material to growers worldwide.
ASBVd, a microscopic RNA molecule that causes avocado sunblotch, can severely impact yield and fruit quality. The disease spreads through infected plant material, seed, pollen and even pruning tools, and with no known cure, prevention remains the only effective line of defence.
© Du Roi Halls Nursery
Commercial effects of infection
The presence of ASBVd in an avocado host can lead to the appearance of severe symptoms such as the formation of coloured, sunken lesions on avocado fruit, discoloured streaks on young stems, and discolouration and malformation of leaves. Although the appearance of these symptoms will not usually lead to death of a healthy avocado tree, fruit symptoms will impact market value of the fruit, and asymptomatic trees may have significantly reduced yield when compared to their uninfected counterparts.
"At Du Roi Halls, we take our responsibility to the avocado industry very seriously," says Kobus Eloff, general manager of Du Roi Halls Nursery. "We go far beyond the minimum regulatory requirements to ensure our plants are free from ASBVd. Every single source tree is tested annually, not just every three years as required, and we conduct additional random tests throughout the year."
© Du Roi Halls Nursery
To further prevent cross-contamination, DRHN maintains physical separation between trees in their genetic blocks through carefully planned root-zone barriers and ditches between every 12 trees, helping contain any potential spread.
Seed sourcing is another key focus. Du Roi Halls obtains avocado seeds from trusted international suppliers and carefully selected local sources, including a dedicated seed orchard near Nelspruit surrounded by non-avocado crops to minimise pollen transfer by bees.
"These measures are not just about compliance; they're about safeguarding the sustainability and reputation of the South African avocado industry," adds Eloff. With more than 12,000 trees under careful management at its Mbombela facility, Du Roi Halls Nursery continues to set the benchmark for clean, clonal avocado plant material. Its work supports growers' productivity, orchard longevity and access to global export markets that demand certified disease-free plant sources.
For more information:
Du Roi Halls Nursery 
Email: [email protected]
duroihalls.co.za/
