Acquisition and quarantine of Saccharum spp. germplasm and related genera in the United States

In the United States the quarantine and indexing of sugarcane germplasm is entrusted to the quarantine unit of the US Department of Agriculture, Agricultural Research Service, National Germplasm Resources Laboratory. Imported germplasm is held in quarantine for 18-24 months. During this time, clones are subjected to a short and a long hot water treatment to eliminate pest and pathogens potentially present in the plants or plant pans. The propagants are observed for disease symptoms during each of the two growth cycles following the hot water treatments. Diagnostic tools applied for pathogen detection include tissue imprinting and immunoassays for leaf scald and ratoon stunt causing bacteria, culture on semi-selective medium for leaf scald bacterium, and bioassays and leaf dip electron microscopy for virus detection. In the past five years, about 455 acquisitions have entered the quarantine from 14 different geographic areas. Less than 5% were retained due to the presence of pathogens. Mosaics and ratoon stunt are the most frequently encountered diseases.