Evidence for a non‐infectious phyllody disease of strawberry

Abstract

A phyllody disease of strawberry suspected to be of phytoplasmal etiology has been observed in the Campania region of southern Italy. The most characteristic symptom was a pronounced foliaceous growth arising from the achenes. Symptomatic fruits developed poorly and were unmarketable. However, the foliage of affected plants appeared normal. Symptom expression was most pronounced from September through December of the planting year, whereas symptomatic fruits were rare in the second crop. The disease, which has also been observed in northern Italy, appears to be restricted to plants grown from cold‐stored runners (frigo plants). To elucidate the etiology of the disease, symptomatic plants were examined for phytoplasmal infection, employing fluorescence microscopy as well as direct and nested PCR assays. However, all plants tested negatively. Also, attempts to transmit the disease to periwinkle or healthy strawberry plants were unsuccesful. Thus, the disease is likely to be of physiological etiology.