Wedoany.com Report-Sept. 10, Rijk Zwaan, a Dutch fruit and vegetable breeding company, has introduced two new iceberg lettuce varieties – Happinas RZ and Friendlinas RZ – featuring high resistance to biotypes 0 and 1 of the blackcurrant-lettuce aphid (Nasonovia ribisnigri, Nr:0,1). This development offers lettuce growers in Europe a timely solution, particularly as EU regulations will soon prohibit the use of systemic pesticides containing Spirotetramat, creating new challenges for aphid control. Peter Sonneveld, Crop Coordinator at Rijk Zwaan, noted: “They are asking themselves how they can stay aphid-free.” Lettuce heavily affected by these aphids is often unsellable, making effective resistance essential.

The high resistance has been proven in multiple field trials

The two varieties are marketed under the Nasonovia Defense™ label and have demonstrated high resistance in field trials conducted over the past year. In conditions with high aphid pressure, susceptible lettuce varieties were heavily infested, whereas Happinas RZ and Friendlinas RZ showed virtually no infestation, highlighting their effectiveness in protecting crops and maintaining marketable quality.

In addition to aphid resistance, the varieties exhibit positive agronomic traits. Trials at 20 growers’ facilities across north-western Europe confirmed strong performance in head shape, base, weight, and tipburn resistance. Sonneveld added: “We’re happy to share the details with growers.” Rijk Zwaan expects sufficient seed availability for the upcoming growing season to meet market demand.

Looking ahead, the company plans to introduce additional lettuce types with Nr:0,1 resistance. Johan Schut, Breeding Manager at Rijk Zwaan, explained: “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.” This approach aims to provide growers with a broader portfolio of disease- and pest-resistant lettuce varieties.

Rijk Zwaan also emphasizes the importance of protecting the effectiveness of the resistance through Integrated Crop Management (ICM). Sonneveld advises growers to monitor pests closely, employ natural predators, use approved biological pesticides, and apply remaining chemical controls prudently to maintain resistance for future seasons.

Growers interested in viewing the new Nasonovia Defense™ varieties can attend Rijk Zwaan’s Demo Days this autumn. The Open Field Demo will be held in Fijnaart, the Netherlands, from 15 September to 10 October, while the varieties will also be showcased at the Pfälzer Feldtag in Germany on 11 September. These events offer an opportunity for hands-on inspection and technical guidance.

By introducing Happinas RZ and Friendlinas RZ, Rijk Zwaan provides European growers with an effective, market-ready solution to combat blackcurrant-lettuce aphids, supporting sustainable and profitable lettuce production while preparing for the EU’s forthcoming pesticide restrictions.