An abnormal sprouting condition in potato tubers has been observed in California sporadically for the past 15 years. The disorder, termed spindling sprout or hair sprout, appears as weak, threadlike sprouts initiating from the eyes of apparently sound tubers. Spindling sprouts have been attributed to such varied causes as potato viruses, fungus infections, psyllid insects and adverse environmental conditions. Preliminary investigations have implicated the aster yellows virus as contributing to spindling sprout in California.

The above progress report is based on Research Project No. H-1665R.