How to Manage Pests

UC Pest Management Guidelines

SYMPTOMS

Symptoms on plants infected with Tobacco mosaic tobamoviruses vary among cultivars and with specific viruses or strains. Symptoms can include necrosis on any plant part, defoliation, leaf distortion, and/or mosaic symptoms on leaves, stems, and fruit.

COMMENTS ON THE DISEASE

An important source of primary inoculum is contaminated seed. The virus is carried on the seed coat, and thus can be removed from contaminated seeds by washing seed with dilute solutions of tri-sodium phosphate. The tobamoviruses on pepper are readily spread mechanically within the field by handling and mechanical damage to plants, but not by insect, nematode or fungal vectors.

The tobamoviruses are very stable viruses. They can survive in plant debris for many years.

MANAGEMENT

The best control is to use seed that has been treated to eliminate the seedborne inoculum. Minimizing plant handling and damage also is important for reducing field spread of tobacco mosaic virus. Good sources of plant resistance genes (L1-L4 genes) to various tobamoviruses also exist and are present in commercially available cultivars. No chemical strategies are effective.

PUBLICATION

UC IPM Pest Management Guidelines: Peppers
UC ANR Publication 3460
Diseases
S. T. Koike, UC Cooperative Extension, Monterey County
R. M. Davis, Plant Pathology, UC Davis
K. V. Subbarao, USDA Research Station, Salinas
Acknowledgment for contributions to Diseases:
B. W. Falk, Plant Pathology, UC Davis

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