3 - 



Table 1, 



Non-viral fruit russet in selected clones of Golden 

 Delicious, in lbs per bushel. 



*Less than a bushel 



Both clones could be marketed as virus-free Golden Delicious. 

 It goes without saying that good "seed" produces better crops than 

 poor "seed." A successful potato farmer insists on knowing the 

 disease rating and potential of his propagative seed and knows 

 what the odds are of planting poor seed. It is paradoxical that 

 apple trees are bought and planted for future envisioned high- 

 yielding crops often without knowing their possible inherent faults 

 or capabilities or virus content simply because there is no "pedi- 

 gree" or labeling system to prevent this from occurring. Somehow 

 a standard system has to be developed to insure that superior germ 

 plasm is protected from viral reinfection as well as to insure that 

 the grower receives specific information certifying that the prod- 

 uct he receives is the quality product the nursery originally 

 started with. 



Progress has recently been made in reducing certain yellows 

 diseases of fruit trees originally thought to be viral in nature 

 but now known to be caused by mycoplasmal pathogens (ultramicro- 

 scopic bodies contained in phloem cells and transmitted by leaf- 

 hoppers). There are also similar sized rickettsial and bacterial 

 type pathogens transmitted by leaf hoppers that affect woody plants. 

 Fruit trees infected with these pathogens respond to antibiotic in- 

 jections and disease symptoms are frequently arrested. Such con- 

 trols are only stop-gap measures as they do not entirely eliminate 

 infections and must be repeated. With viral infections there are 

 not even stop-gap chemicals and a tree once infected in the orch- 

 ard or infected when planted stays infected for the life of the 

 tree. It is true that the possibility of reinfection with a virus 

 may occur with insects as in other plants; however, to date, this 

 has not been shown to happen with the apple virus entities. We, 

 still do not know what relationship the so-called latent and seem- 

 ingly inocuous apple viruses have to other plants and should 

 not continue to spread these around in infected budwood sources. 



