Producing bulbs and perennials : sustainable control of diseases, pests and weeds

In the Netherlands every year flower bulbs and perennials are produced representing a value of € 500 m (flower bulbs) and of € 65 m (perennials, 2004). The growers are faced with several threatening pests and diseases during the production. They usually deal with these problems by using pesticides. In 2004 the Ministry of Agriculture and the stakeholders in Agribusiness made an agreement on reducing the environmental impact of pesticides by developing and implementing knowledge on Integrated Crop Protection. As a result growers were expected to control pest and disease problems using effective and sustainable solutions. Sustainable control methods have been developed to control the plural problems the growers encounter during the production and postharvest phase of flower bulbs and perennials. These methods include using clean plant material, decision support systems, pesticides with a low environmental risk, biocontrol agents, natural enemies, pesticide emission reducing techniques, methods for manipulating soil health, etc. These methods were tested not only under experimental conditions at the Applied Plant Research Centre (PPO) Lisse but also under practical conditions at farmers. In this way methods were evaluated for their robustness under different situations (location, farm size, climate conditions). Several examples of the development of preventive and control methods and how they can be applied in integrated crop protection strategies and should be implemented in practice are discussed.