Collecting, conservation and utiklization of plant genetic resources and their global distribution are essential componentes of international crop improvement programmes. Inevitably, the movement of germplasm involves a risk of accidentally introducing plant quarantine pests*along with the host plant material; in particular, pathogens that are often symptomless, such as viruses, pose a special risk. In order to minimize this risk, effective testing (indexing) procedures are required toensure that distributed material is free of pests that are of quarantine concern. The ever-incrrrreasing volume of germplasm exchanged internationally, coupled with recent rapid advances in biotechnology, has created a pressing need for crop-specific overviews of the existing kno.

The technical guidelines are written in a short, direct, sometimes telegraphic style, in order to keep the volume of the document to a minimum and to facilitate updating. The guidelines are divided into two parts. The first part makes general recommendations on how best to move germplasm of the crop concerned and mentions available intermediate quarentine facilities when relevant. The second part covers the important pests and diseases of quarentine concern. The information given on a particular pest or disease does not pretend to be exhaustive but concentrates on those aspects that are most relevante to quarentine. Where possible, acronyms for viruses are according to Hull et. al (1991).

Technical recommendations. Seed. Pathogen-tested in vitro cultures. Cuttings form pathogen-tested in vitro cultures. Untested vegetative material. Descriptions of pests. Viral diseases. Viruses not known to cause disease. Virus-like disease. Procaryotic diseases. Fungal diseases. Arthropod pests.