Verticillium Wilt in Spinach Seed Production

Area of Science:

• Plant Pathology
• Agricultural Science
• Mycology

Background:

• Verticillium wilt is a significant disease affecting various crops.
• Spinacia oleracea (spinach) is a globally important vegetable crop, with primary seed production in the United States.
• No prior reports of Verticillium wilt existed for fresh and processing spinach in the U.S.

Purpose of the Study:

• To report the first occurrence of Verticillium wilt in U.S. spinach seed crops.
• To investigate the prevalence and pathogenicity of Verticillium dahliae in spinach seed.
• To determine the potential for seed transmission of Verticillium wilt in spinach.

Main Methods:

• Symptomatic spinach seed crops in the Pacific Northwest were sampled.
• Seed lots from various global origins were tested for Verticillium spp. presence.
• Pathogenicity assays using root-dip inoculation were performed on spinach cultivars.
• Systemic movement and seed-to-seed transmission of V. dahliae were investigated.

Main Results:

• Verticillium dahliae was identified in a 2002 hybrid spinach seed crop in the U.S. Pacific Northwest.
• High incidences of Verticillium spp. (89%) were found in commercial spinach seed lots globally.
• Five V. dahliae isolates proved pathogenic to three spinach cultivars.
• Systemic movement and seed-to-seed transmission of V. dahliae were confirmed.

Conclusions:

• This study reports the first incidence of Verticillium wilt in U.S. spinach seed production.
• Verticillium spp. are prevalent in commercial spinach seed, posing a significant risk.
• Seed-borne V. dahliae can cause disease and transmit systemically, necessitating stringent seed health monitoring.