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Occurrence of Ergot (Sugary Disease) Incited by a Sphacelia sp. on Sorghum in Mississippi in 1997

May 1998 , Volume 82 , Number  5
Pages  590.4 - 590.4

N. Zummo , Department of Entomology and Plant Pathology, Mississippi State University , L. M. Gourley , Department of Plant and Soil Sciences, Mississippi State University , and L. E. Trevathan and M. S. Gonzalez , Department of Entomology and Plant Pathology, Mississippi State University, Mississippi State 39762 ; and J. Dahlberg , USDA, ARS, Mayaguez, Puerto Rico

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Accepted for publication 6 March 1998.

Ergot (sugary disease) incited by a Sphacelia sp. was observed on Sorghum bicolor (L.) Moench var. Sweet Leaf II at Leland and Pop-larville, MS, in October 1997. The disease was characterized by droplets of a thick, sticky, semi-transparent secretion similar to aphid honeydew. The caryopsis of infected florets was converted to relatively soft, chalky pink, tumescent, immature sclerotia (1.5 to 1.7 × 4 mm) with blunt ends. Abundant conidia (11 to 17 × 5 to 7 μm) were produced on stromatic tissue and in large numbers in the sugary secretion. This fungus is similar to that described by Zummo in West Africa (2). Velazquez-Valle et al. (1) recently reported the distribution of Claviceps africana Frederiksen, Mantle & de Milliano in the United States in 1997. The Sphacelia stage of the fungus found in Mississippi is similar to that reported from other areas of the U.S. Our report extends the range for this fungus, which is contiguous to those areas reported by Velazquez-Valle et al. (1).

References: (1) R. Velazquez-Valle et al. 37th Annu. Mtg. Carib. Div., Am. Phytopa-thol. Soc., San Jose, Costa Rica, No. 77, 1997. (2) N. Zummo. 1984. Sorghum Diseases in West Africa. An Illustrated Text. USDA/USAID, Zaria, Nigeria.

© 1998 The American Phytopathological Society