How to Manage Pests

UC Pest Management Guidelines

SYMPTOMS AND SIGNS

Beet yellow stunt causes pronounced yellowing of older leaves; later, infected plants collapse prematurely and die. Internally, the phloem tissue of the stem and crown is brown and necrotic.

COMMENTS ON THE DISEASE

Host range of Beet yellow stunt virus includes plants in the families Chenopodiaceae, Asteraceae, Geraniaceae, Portulacaceae, and Solanaceae. Beet yellow stunt causes minor losses in most years, but occasionally is responsible for major losses in individual lettuce fields. The virus is transmitted by aphids. The sowthistle aphid, Hyperomyces lactucae, is the most efficient vector. Sowthistle (Sonchus spp.) is the primary source of the virus, and the disease is damaging only where large concentrations of sowthistle are present.

MANAGEMENT

General weed control, especially of Sonchus spp., reduces the incidence of this virus in lettuce.

PUBLICATION

UC IPM Pest Management Guidelines: Lettuce
UC ANR Publication 3450
Diseases
S. T. Koike, UC Cooperative Extension, Monterey County
R. M. Davis, Plant Pathology, UC Davis

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