- One of the most important decisions growers make is the choice of planting stock. The right variety and clone matched to the right site is a solid foundation for success. But choosing planting stock involves more than choosing the genetic make-up of the grape. Grapes are hosts to a large range of biotic guests: fungi, bacteria, mycoplasmas, viruses, insects, and nematodes all can be carried on, or in, grape plant material. If the choice of plant material does not include consideration of these factors, then growers could be incorporating serious problems into the vineyard, both for themselves and their neighbors. There is no surer way to be unsure about these factors than by smuggling plant material. There has been a quarantine in Oregon since the 1930's and the current regulations allow importation only of certified cuttings or certified plants grown in sterile, soilless media. This program has been successful in maintaining the health of Oregon vineyards. There are only two serious diseases that occur in Oregon every year: botrytis and powdery mildew. There are many other pests and diseases that would do just fine in our climate and soils, if they could just get started. It is the responsibility of every grower in Oregon to see that they don't. The following article is a list of problems we don't have, but could.