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ARS Home » Research » Publications at this Location » Publication #178596
Title: INCIDENCE OF SOUTHERN BLIGHT OF OKRUN PEANUT GROWN IN SOIL PREVIOUSLY PLANTED TO SCLEROTIUM ROLFSII-INFECTED WEEDS AND PEANUT

Author
item MEADOR, CHRISTOPHER - OKLAHOMA STATE UNIV
item Melouk, Hassan
item MURRAY, DON - OKLAHOMA STATE UNIV

Submitted to: American Peanut Research and Education Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 12/12/2005
Publication Date: 2/1/2006
Citation: Meador, C.B., Melouk, H.A., Murray, D.S. 2006. Incidence of Southern Blight of Okrun peanut grown in soil previously planted to Sclerotium rolfsii-infected weeds and peanut [abstract]. Proceedings of the American Peanut Research and Education Society. 37:37-38.

Interpretive Summary:

Technical Abstract: Incidence of Southern Blight (SB) on Okrun peanut was determined in soil previously planted to weeds and peanut that were inoculated with Sclerotium rolfsii. Five weeds (Crownbeard, Eclipta, Jimsonweed, Pitted morningglory and Sicklepod) and two peanut cultivars, Okrun and Southwest runner, were grown in bulb pans (30 cm dia) for 5-7 weeks at three plant densities (1,4 or 8 plants/0.093 m2). Individual plants within each bulb pan were inoculated with S. rolfsii. Each bulb pan was enclosed in a clear polyethylene bag (38.1x 91.44 cm) that was tied at the top forming an enclosure to ensure relative humidity of more than 95% for two days. Polyethylene bags were opened at 2 days post-inoculation (DPI). Lesions on infected plants were measured at 2,3,4,5 & 6 (DPI). The polyethylene bags were then removed and the plants were allowed to dry for four weeks. The dried plant material was incorporated into the soil of each bulb pan, and four seeds of Okrun peanut were planted in each. Rate of lesion expansion and area under lesion expansion curve on Jimsonweed and Pitted morningglory were significantly higher (p=0.05) than on Okrun, Southwest runner and Eclipta. Incidence (%) of SB on Okrun planted following infected weeds and peanut was recorded throughout the season until the plants reached maturity (150 days after planting). The Okrun plants were then dug, and percent of S. rolfsii- infected pods was determined. Soil samples were collected from each bulb pan quantify viable sclerotial density. Disease incidence on Okrun following infected Sicklepod was significantly higher (p=0.05) than all other weeds or peanut which were not significantly different from one another. Peanuts grown behind Crownbeard, Sicklepod and Southwest runner all had significantly higher (p=0.05) percentages of infected pods than Pitted morningglory, Jimsonweed and Eclipta. Sclerotial density in soil following peanut harvest showed no effect due to plant species, but plant density was significant, with 1plant/0.093 m2 having significantly lower sclerotial densities than 8 plants/0.093 m2 and 4 plants/0.093 m2 was not significantly different from either of the others (p=0.05) .