A severe outbreak of crown and root rot of tomato caused by Fusarium oxysporum f. sp. radicis-lycopersici in Malta

Abstract

A severe outbreak of crown and root rot of tomato was observed in greenhouses in Malta in eight locations during the period November 2004 – February 2005. Besides root and crown symptoms, several plants showed cankers at the basal part of the stem. Fusarium oxysporum was constantly isolated from these plants. One isolate from each location was tested for pathogenicity on tomato seedlings. All these isolates caused severe necrotic lesions of the crown and roots, and stem cankers. It was concluded that F. oxysporum f. sp. radicis-lycopersici (FORL) was the cause of the outbreak. Incidence ranged from 10 to 50%. Cold weather conditions occurring in Malta during the late fall and winter of 2004–2005 probably favoured the disease. The use of tomato cultivars or hybrids resistant to FORL is suggested for winter tomato crops in south Mediterranean areas.