Net blotch of barley

Symptoms

The spots are brown and oval, with a pale yellow margin and a dark grey coating. They do not merge and have dark transverse and longitudinal streaks that form a net pattern.

When to look

• Barley helminthosporiosis, including net blotch, is assessed on the second and third leaves 10–12 days after heading.
• Helminthosporium leaf spots, including net blotch, are already seen at the spring tillering stage. In warm, wet weather in May–June they appear on a mass scale at the grain formation stage.

How to count

• Barley helminthosporiosis, under which the book also places net blotch, is assessed on the Peterson scale on the second and third leaves, counting from the top.
• If plant death is noticeable when assessing barley helminthosporiosis, the percentage of dead plants is determined: 20 plants are examined at five places on the plot in each of two replicates.

No rate and no spray timing here: both come from the label and the register.

Every fact rests on a quote from its source, and each quote was checked against the page it is printed on.

1. EPPO Global Database · European and Mediterranean Plant Protection Organization
2. Станкевич С. В., Положенець В. М., Немерицька Л. В., Журавська І. А., «Моніторинг хвороб сільськогосподарських культур», навчальний посібник, 301 с. · Інститут біоенергетичних культур і цукрових буряків НААН, Державний біотехнологічний університет; Житомир: Рута, 2022 · p. 158, 159
3. Прогноз фітосанітарного стану агроценозів України та рекомендації щодо захисту рослин у 2025 році · Держпродспоживслужба, НААН, НАН · p. 44