Cereals: Barley Yellow Dwarf Virus

Excerpt from Agronomy Guide for Field Crops (Chapter 6)

Order OMAFRA Publication 811: Agronomy Guide for Field Crop

Table of Contents

1. Incidence
2. Appearance
   • Comparison of BYDV, SBWMV and WSSMV - Table 6-23
3. Disease Cycle
4. Management Strategies
5. Updates on Cereals: Barley Yellow Dwarf Virus
6. Related links...

Incidence

Barley yellow dwarf virus (BYDV) has been called the most widely distributed and most destructive virus disease of cereals. It has been found in Canada, the U.S., Europe, Australia, Asia, New Zealand, Africa and South America. BYDV attacks a wide range of grass hosts, including wheat, oats and barley. Of these, oats are considered the most susceptible.

Appearance

The primary symptoms are stunting and yellowing, reddening or purpling of the leaf tips.

Plate 114. Barley yellow dwarf virus (BYDV) is transmitted by aphids. Symptoms are stunting and yellowing with reddening or purpling of leaf tips.

Plate 115. Red leaf is the main symptom of BYDV on oats.

Barley yellow dwarf virus is often confused with other virus diseases (spindle streak mosaic virus, soil-borne mosaic virus - see Table 6-23, Comparison of BYDV, SBWMV and WSSMV), nutrient deficiency or environmental causes. Identifying viral pathogens is very difficult and requires accurate serological tests. It is best to send samples to a diagnostic lab with these capabilities.

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Disease Cycle

Barley yellow dwarf virus is transmitted by aphids only. Several species of aphids have been identified as vectors for BYDV, including the greenbug, the corn leaf aphid, the English grain aphid and the bird cherry-oat aphid. Damage occurs as a result of aphid feeding, since aphids feed directly on a plant's sap and therefore reduce the nutrients available for plant growth. The contact with the plant sap makes aphids ideal vectors for BYDV. It is usually found in patches 1-2 m in diameter but can occur uniformly throughout the field if aphid populations are also uniform throughout the field. Yield losses are very dependent on the crop stage when infected. Generally, losses are greater when infection occurs on young seedlings in the fall (>30%) rather than in the spring.

Management Strategies

Few control options are available. The best strategy is to avoid early planting. Early planting allows the aphids more time to infect the plants in the fall. Recommended or optimum planting dates for winter wheat take into consideration barley yellow dwarf virus and Hessian fly and promote a vigorous plant to maximize winter hardiness (see the section Planting Dates). Planting earlier during mild or late autumns allows the aphids to survive longer than usual. Early seeding is an advantage in spring grains. Chemical sprays to control the aphid vectors are not practical or economical, since scouting or detecting the aphids is very difficult. By the time populations reach detectable levels, virus transmission has most likely already occurred. Preventative sprays would not be economic as BYDV is unpredictable.

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Updates on Cereals: Barley Yellow Dwarf Virus

No updates available at this time.

Related links...

• Diseases
• Cereals
• Field Crop Protection Guide - Publication 812

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