Myrothecium Leaf Spot
Myrothecium roridum Tode ex Fr
Symptoms: Water-soaked oval spots on leaves rapidly
increase in size and turn dirty brown. Necrotic tissue can crack
and develop holes.
Pathogen and disease characteristics: In culture, sporodochia
are sessile, up to 1.5 mm in diameter, and often confluent. Spore
masses are viscous and green at first, later becoming hard and
black. No setae in sporodochia. Conidia are cylindrical with rounded
ends, colorless to pale olive green to black in mass, and mostly
6-8 × 1.5-2.5 µm (Ellis 1971,
Host range: Pearl millet guar [Cyamopsis tetragonoloba
(L.) Taub], moth (Phaseolus acontifolius Jacq.), black
gram (Phaseolus mungo L.), green gram [Vigna radiata
(L.) Wilkzee], pigeonpea [Cajanus cajan (L.) Millsp.],
cowpea (Vigna sinensis Endl.), pea (Pisum sativum
L.), soybean (Glycine max Merr.), peanut (Arachis hypogaea
L.), okra [Abelmoschus esculantum (L.) Moench.], cotton
(Gossypium hirsutum L. and Gossypium arboreum L.),
potato (Solanum tuberosum L.), tomato (Lycopersicum
esculentum Mill), eggplant (Solanum melongena L.),
wheat (Triticum aestivum L.), maize (Zea mays L.)
Geographic distribution: India. A Myrothecium
species has been isolated from pearl millet stalks in the United
States, but the species appears to be M. verracaria (J.P.
Wilson, personal observation).
Nomenclature discrepancies: None.
Seed transmission: Can be isolated from seed (Girisham
et al. 1985).
Primary citations: Ellis 1971,
Department of Agriculture
The material on this page is in the public
Original posting: June 5, 1999.