Resistance against aphids

Lettuce varieties with resistance to the currant-lettuce aphid (Nasonovia ribisnigri) are being introduced across Rijk Zwaan’s breeding programmes. Our new varieties are delivering high resistance (HR) to both Nr:0 and Nr:1 biotypes, with strong agronomic performance in field trials. Nasonovia Defense™ gives growers a powerful tool in their IPM toolbox - offering natural protection even when other aphid-control options are limited.

What is Nasonovia?

Nasonovia, or the currant-lettuce aphid (Nasonovia ribisnigri), is a major sap-sucking pest, notorious for colonising deep inside the heart and inner leaves of lettuce, making infestations difficult to detect and control. The aphid damages crops by feeding on the plant's sap, distorting leaves and stunting growth. They also act as a vector for plant viruses and promote fungal infections, all leading to unmarketable produce.

Challenges for lettuce growers in Australia

• Pesticide resistance
  Some populations of Nasonovia ribisnigri have developed resistance to certain chemical pesticides.

• Hiding behaviour
  The aphid's habit of living deep inside the lettuce head makes it difficult to reach with many control methods, and makes even small infestations unmarketable.

• Rapid reproduction
  The aphid reproduces quickly, making traditional control methods less effective against large populations.

• New biotypes
  The aphid has evolved to overcome previously effective genetic resistance. The emergence of new resistance-breaking biotypes, such as the "Nr:1" biotype, means that natural resistance in some lettuce varieties is no longer working.

How does the resistance work?

Rijk Zwaan’s Nasonovia Defense™ lettuce varieties carry a natural genetic resistance that stops the currant-lettuce aphid (Nasonovia ribisnigri) - including the challenging Nr:1 biotype - from feeding on the plant.

Because the aphids can’t feed, they can’t reproduce or build colonies inside the heart, preventing the rapid spread that makes this pest so hard to manage. This high resistance (HR) helps protect heads from contamination and relieves pressure on other control methods.

This resistance offers a strong and reliable layer of protection. The result is an easier-to-manage crop that the aphids aren't attracted to - giving you confidence to meet market demand and grow with peace of mind.

Field trials confirm strong results

Before we introduce a Nasonovia Defense variety, it goes through extensive testing. In both lab and field trials under high aphid pressure, the resistance has proven effective against both Nr:0 and Nr:1.

We also assess how each variety performs under real growing conditions. That means checking yield, quality and consistency in the field. The results speak for themselves. These new varieties match or even outperform today’s market references.

Plan to protect your crop

To discuss availability and arrange trials of lettuce with high resistance (HR) to currant-lettuce aphid (Nasonovia ribisnigri, Nr:0 and Nr:1 - contact us today.