Downy Mildew
Plasmopara penniseti Kenneth & Kranz.
Symptoms: Small, diffuse, water-soaked stripes or spots
expand to irregular brown stripes between the veins. Stripes may
coalesce and turn necrotic. Streaks may enlarge beyond veins and
turn greyish brown. "Down" of asexual sporulation is
profuse and whitish to dingy. Only local lesions form. Usually
only the lower leaves are affected.
Pathogen and disease characteristics: Sporangiophores
emerge from stomata, branched dichotomously once or twice, then
irregularly branched monopodially to subdichotomously two or three
times at right angles. Oospores have not been observed.
Host range: Pearl millet.
Geographic distribution: Ethiopia.
Nomenclature discrepancies: Use of "downy mildew"
as the common name for this disease may cause confusion with the
more serious systemic disease caused by Sclerospora graminicola.
Seed transmission: Not known to be transmitted by seed.
Primary citations: Kenneth and
Kranz 1973.
United States
Department of Agriculture
Agricultural
Research Service
The material on this page is in the public
domain.
Original posting: June 5, 1999.
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