How to Manage Pests

UC Pest Management Guidelines

SYMPTOMS

Symptoms are similar to those caused by aphid-transmitted beet yellows virus. Early symptoms are a very mild mottle that later develop into interveinal yellowing or reddening. Affected plants are stunted. Vascular rings in roots are brown and mature tap roots often appear to be pithy.

COMMENTS ON THE DISEASES

Lettuce infectious yellows used to be a problem on sugarbeets grown in the Imperial Valley. It was transmitted by the sweet potato whitefly, Bemisia tabaci, which has been displaced by the silver-leaf whitefly, Bemisia argentifolii– a nonvector of this virus. Currently, lettuce infectious yellows is not a major concern. The damage potential of lettuce chlorosis is not yet known.

MANAGEMENT

Plan planting schedules of host crops (melons, lettuce, and squash) so that a 2- to 3-week host-free period occurs in July or August. Do not plant sugarbeet until host crops in the area are harvested and host weeds, such as wild lettuce and sunflower, are destroyed. Insecticides applied to control the whitefly vector on sugarbeet or other crops will reduce the vector population briefly, but do not help prevent the spread of the virus.

PUBLICATION

UC IPM Pest Management Guidelines: Sugarbeet
UC ANR Publication 3469
Diseases
S. Kaffka, Agronomy and Range Science, UC Davis
R. T. Lewellen, USDA, Salinas
C. A. Frate, UC Cooperative Extension, Tulare Co.
T. A. Turini, UC Cooperative Extension, Imperial Co.

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