Determination of spatiotemporal stability of corn head smut(Sporisorium reilianum) by SADIE

Abstract

J.F. Ramirez-Davila, J.R. Sanchez-Pale, E. Porcayo-Camargo, and C. de Leon. 2012. Determination of spatiotemporal stability of corn head smut ( Sporisorium reilianum ) by SADIE. Cien. Inv. Agr. 39(3): 459-471. Recently, S. reilianum has caused significant ecological and economic damage in the maize-producing areas of Mexico and other countries. Knowledge about the spatiotemporal stability and distribution of the disease is important for the development of integrated management programs. The present study was performed to model the spatial distribution of S. reilianum from 2006 to 2009 using geostatistic techniques and to determine the spatiotemporal stability of corn head smut via a spatial analysis by distance indices (SADIE) and the Cramer-von Mises test. The incidence of the disease was determined in 100 corn parcels located in Santa Magdalena Valle de Bravo Municipality, and the parcel locations were determined with dGPS. The spatial distribution analysis was performed using spatial statistics (Geostatistic and SADIE). Aggregation maps were developed; and the long term spatiotemporal stability was determined with the Cramer-von Mises test and the SADIE association index. The results showed that geostatistics were able to establish S. reilianum spatial patterns, visualizing its centers of aggregation through elaborated maps. Such aggregation enables adequate management actions in terms of points or specific sites. The association index of SADIE (Im) and the bi-variable Cramer-von Mises (Ψ) proof make it possible to determine the spatiotemporal stability of the disease over the four years of the study.