Molecular Diagnostics in Plant Health

In several crops, their quality and condition is very important. The products are relatively expensive and plant diseases can destroy valuable harvests in a very short time. The presence or absence of plant pathogens and pests, therefore, needs to be accurately tested. For decades, identification and detection methods have been designed to demonstrate that starting material for further propagation and also certified bulbs, tubers, cuttings, and plants are free of many plant pathogens. Every year, millions of plants are tested, including approximately one and a half million bulbs. Despite the ease of low-cost, fast, and well-automated test methods, such as ELISA, more and more molecular-based techniques are used the last decade. These techniques are, generally, more specific and more sensitive. These new tests are also necessary because plant pathogens are often latent (asymptomatic) present in the material to be tested. The Netherlands has a high in—and export of plants and plant products. These large trading volumes may harbour many plant pathogens. The European Commission has drawn up a list of unwanted plant pathogens (quarantine organisms). This list contains more than 300 different organisms (viruses, bacteria, fungi, phytoplasmas, nematodes and insects). Each EU-country has to control the in—and export traffic of plants and plant products for the introduction of these unwanted organisms. In the Netherlands, this task is performed by four inspection services: Naktuinbouw (Netherlands Inspection Service for Horticulture), NAK (The Dutch General Inspection Service), BKD (Inspection Service for Flowerbulbs) and KCB (Quality Control Bureau). The NVWA (Dutch Food and Consumers Authority) is the NPPO (National plant protection organisation) in the Netherlands and supervises the inspection services. Many different molecular methods are used daily for the detection and identification of many plant pathogens and plant diseases.