EPIDEMIOLOGY OF BARLEY YELLOW DWARF - A STUDY IN ECOLOGICAL COMPLEXITY

Barley yellow dwarf virus (BYDV) is the most widespread and economically significant virus disease of cereals worldwide, affecting >100 species of Poaceae, including barley, wheat, oats, sorghum, rye, triticale, maize, rice and many wild grasses. The components of the pathosystem are outlined, looking at BYDV variants, their host plants and their aphid vectors. The complexities of the pathosystem include how BYDV alters host plant biology (particularly growth and metabolism); how host plants interact with the environment to alter vector viology; and how BYDV itself alters vector biology. Epidemiology is reviewed and prospects for management of the disease are discussed, paying attention to breeding for host plant resistance, use of pesticides and crop environment manipulation. -P.J.Jarvis