Abstract

MARINELLI, A.; MARCH, G.J.  and  ODDINO, C.. Biological and epidemiological aspects of peanut smut (Arachis hypogaea L.) caused by Thecaphora frezii Carranza & Lindquist. Agriscientia [online]. 2008, vol.25, n.1, pp.1-6. ISSN 1668-298X.

Smut was first detected in peanut plants cultivated during the agricultural cycle 1994/95, and since then it has been observed only in some commercial peanut fields, with low incidence. Due to the importance of peanut crop for Cordoba (Argentina), and to the fact that 80% of the production is assigned to exportation, biological and epidemiological aspects of the disease were studied. Flower and soil inoculations were made under controlled conditions in order to accomplish Koch's postulates, and to detect the sites and forms of infection by the fungus. Partially infected seeds as well as externally contaminated seeds were employed. To detect and quantify the disease through prevalence and incidence, field monitoring was carried out over seven crop years, and a methodology that allowed pathogen detection from soil samples was performed. The conclusion arrived at is that Thecaphora frezii is the causal agent of smut of cultivated peanut, and that the infection is localized, occurring in the peg when it penetrates the soil. The only colonised organs are the fruits and the seeds which can be transformed into carbonose mass. The dispersion of the fungus would be through infected or externally contaminated seeds. The pathogen survives in the soil and its detection is possible by taking soil samples and by observing the teliospores under a microscope. Prevalence oscillated between 9 and 24% of the monitored fields, while incidence varied between 0.13% and 2.7%; only one field with 6.4% was detected.

Keywords : Peanut smut; Epidemiology.

        · abstract in Spanish     · text in Spanish     · Spanish ( pdf )