Pb Defense
Pb Defense offers protection against clubroot (Plasmodiophora brassicae) in cauliflower.
Rijk Zwaan’s Pb Defense cauliflower varieties have natural resistance against infection with clubroot, a disease that can be a serious problem for cauliflower growers worldwide. This protection restricts the growth and development of clubroot effectively, without resulting in any loss of yield or quality for cauliflower growers. Pb Defense is part of Rijk Zwaan’s Defense label.
Interested in Pb Defense varieties?
Please contact:
Merek Dorf
Why growers choose for Pb Defense
The clubroot pressure is increasing in cauliflower on almost all continents worldwide, albeit to a different extent in different regions. Growers who choose cauliflower varieties with Pb resistance can reduce their use of crop protection agents. Since the crop is also healthier and more productive, Pb Defense gives cauliflower growers greater peace of mind throughout the entire crop cycle.
Benefits of Pb Defense
- A healthier crop
- A higher yield
- Harvest uniformity
- Predictable cycles

Cauliflower varieties with Pb Defense
Rijk Zwaan offers a growing number of cauliflower varieties with Pb resistance. These varieties are indicated by both the Pb Defense label and their name, which always starts with a letter ‘P’ (such as Paxton RZ). All the Pb Defense cauliflower varieties combine a short growing period with a uniform harvest and include integrated resistances to the known clubroot races Pb:0, Pb:1 and Pb:3.

Clubroot in susceptible cauliflower varieties
Signs of an infection with clubroot in cauliflower tend to appear as the plant gets older. Symptoms include wilting or yellowing due to the formation of characteristic galls which reduce the water and nutrient uptake in the roots. As these clubs or spindles on the roots continue to grow, they hinder the plant’s development.
Clubroot thrives in high temperatures and wet conditions. It is extremely difficult to control and can cause significant damage to cauliflower production since most of the infected plants will eventually die.

Minimising the risk of spread
Although Rijk Zwaan’s Pb Defense varieties are resistant against clubroot, there is no guarantee of 100% protection. Therefore it is still essential to work with well-balanced crop rotation, strive for a neutral PH level, maintain good air movement and water flow in the soil, and tackle cruciferous weeds.