• Severities of
scab were quite low in both wheat and barley—rains and high humidities that favor scab infection occurred either too early or too late in most cases. • Tan spot and Septoria, fungal leaf-spot diseases affecting
wheat, were common and most severe in the central, east central and southeast parts of the state.
• Septoria, net blotch and spot blotch were the most common diseases of barley for 1999.
• Barley yellow dwarf
virus (BYDV) was observed extensively in wheat and barley in 1999. The disease causes yellowed, stunted plants. Late crops are most vulnerable because the common grain aphids that transmit the disease migrate and build
up populations later in the growing season.
• Wheat leaf rust was much more widespread and severe than in recent years across ND except in the northwest part of the state district.
• Two main reasons
for the rust outbreak: What appears to be a new mix of leaf-rust races in the region, and a buildup of rust spores in the southern Great Plains states last spring that blew northward on air currents and served as
inoculum for fields here.
Highlights from a survey of more than 900 small grain fields from first leaf through the hard-dough stage of kernel development in ND in 1999, according to Marcia
McMullen, NDSU extension plant pathologist.
