Rijk Zwaan USA has introduced the first Salanova multi-leaf variety – Hirst RZ – with high resistance against biotypes 0 and 1 of the extremely troublesome blackcurrant-lettuce (red) aphid Nasonovia ribisnigri (Nr:0,1).
The new resistance creates an extra option in the battle against the blackcurrant-lettuce aphid (Nasonovia ribisnigri). Growers face substantial risks because lettuces affected by the aphids are difficult to sell.
© Rijk Zwaan
High resistance proven in field trials
New lettuce varieties – which are being marketed under the Nasonovia Defense label – have come at just the right time for growers, representing a significant step towards securing lettuce production. The high resistance has been proven in multiple field trials by Rijk Zwaan over past years. When pest pressure was high, susceptible lettuce varieties became heavily infested by blackcurrant-lettuce (red) aphids. In contrast, the researchers found hardly any aphids in the high-resistance varieties in the same field.
More lettuce types with Nr:0,1 resistance in the pipeline
Rijk Zwaan has released a multi-leaf butter variety – Hirst RZ – for the American market.Growers can expect to see varieties of other types of lettuce with the same resistance before too long. Johan Schut, Breeding Manager at Rijk Zwaan, explains: "Our team is busy crossing the resistance into other lettuce types for each market. Furthermore, our goal is to combine the Nr:1 resistance with the complete package of resistances against Bremia races and against the soilborne fungus Fusarium."
Protecting the resistance
To help protect the resistance for the future, Rijk Zwaan advises growers to apply every aspect of Integrated Pest Management (IPM). Among other things, that means monitoring pests, using natural predators and biological pesticides, and controlling aphids with the chemical agents that are still permitted.
For more information:
Rijk Zwaan
Burgemeester Crezéelaan 40
2678 ZG, De Lier
Email: [email protected]
www.rijkzwaan.com
