The importance of barley yellow dwarf virus (BYDV) infection in spring barley and opportunities to manage the disease

Summary

Sector:
Cereals & Oilseeds
Project code:
PR206
Date:
01 February 1996 - 31 January 1999
Funders:
AHDB Cereals & Oilseeds.
AHDB sector cost:
£70,294 From HGCA (Project Number: 1236)
Project leader:
M Carver, R Overthrow, J Lucas and S Phillips

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pr206-final-project-report

About this project

Abstract

Barley Yellow Dwarf Virus (BYDV) is an aphid transmitted disease which can severely reduce the yield of barley. Management techniques to control BYDV infection in autumn sown barley are now well understood and regularly adopted. However BYDV can also cause severe problems in spring sown barley and the full extent of the problem has only been realised since the introduction of varieties possessing tolerance of BYDV infection.

Control of BYDV infection primarily revolves around control of the vector, the aphid. As the autumn progresses and temperatures decrease management techniques have been timed to control primary infections (infected aphids flying into crops) before secondary infections (infected aphids moving within crops) develop. Both foliar sprays and seed treatments can be successfully used to control aphids in the winter sown crops. Control in the spring sown barley crop has always been considered to be more difficult. BYDV infections have tended to increase as the spring progresses as temperatures rise thereby encouraging more aphid activity. It has not been considered feasible to use foliar insecticides as a reliable method of control as primary infection will always be taking place as temperatures increase in the spring.

However the potential of both BYDV resistance in varieties and the seed treatment imidacloprid in reducing the incidence of BYDV infections in spring sown barley crops were considered to be important and were evaluated in a series of trials conducted over three seasons.

Three varieties of spring barley, (two resistant to BYDV - CORK and OPTIC and one susceptible to BYDV - DERKADO) were drilled on two drilling dates at four locations in England. Treatments involving both seed and foliar applied insecticides were compared over the three seasons of the study.

BYDV infection levels were heavy in one season but not severe in the other two seasons, and whilst the susceptible variety did exhibit more BYDV infection the differences between varieties were not as marked as had been anticipated.

Delaying the drilling date, typically by about one month from March to April had a marked effect on yield the greatest reduction from later drilling being in the season that illustrated the highest BYDV infection levels. Later drillings reduced yields by 14.9% to 37.6% and the overall average over the three seasons of trials was -26.9%.

The different combinations of insecticidal seed treatment and foliar insecticide application produced very inconsistent results, and no treatment satisfactorily controlled primary BYDV infections from in flying aphids.

The main management techniques to reduce the impact of BYDV infection on spring barley crops would appear to be earlier drilling dates and the use of resistant varieties.

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