Blister smut of maize

Symptoms

Galls of various shapes and sizes form on the leaves and tassels, and most often on the stems and cobs.

Signs of the pathogen

As the grain ripens, the contents of the galls turn into a mass of black-olive spores covered with a greyish, shiny membrane.

When to look

Smut is assessed before tassel emergence and again at wax ripeness of the grain.

How to count

Examine 25 plants at 10 points along the diagonal of a field of no more than 100 ha. Divide larger areas into two parts and determine the average plant infection on each.

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

Agronomy

The disease can be limited by growing resistant hybrids, following crop rotation and the application rules for post-emergence herbicides, protecting plants from the European corn borer, and chopping and ploughing in post-harvest residues.

Favourable conditions

The disease spreads more when air temperatures are low and there are brief showers at the start of active leaf formation, and when it is dry at the end of leaf formation and during maize flowering. It also needs plant damage from pests, farm machinery or hail, and an existing inoculum reserve of the pathogen.

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. 167
3. Прогноз фітосанітарного стану агроценозів України та рекомендації щодо захисту рослин у 2025 році · Держпродспоживслужба, НААН, НАН · p. 62
4. Photos: Flocci Nivis, Wikimedia Commons, CC BY 4.0 · Nolanna, Wikimedia Commons, CC BY-SA 4.0 · Schlaghecken Josef, Wikimedia Commons, CC BY-SA 4.0 · Svencapoeira, Wikimedia Commons, CC BY-SA 4.0