Empirical Predictions of Wheat Head Blight in the Northern Argentinean Pampas Region

Abstract

Fe and Có rdoba provinces, respectively (Galich and Galich, 1996). Assays in Pergamino (Buenos Aires prov-In Argentina, head blight (caused by Fusarium graminearum ince) showed that kernel number rather than kernel size Schwabe), is a highly risky disease of wheat (Triticum aestivum L.was seriously affected as a consequence of pathogen emm. Thell), although its occurrence is sporadic, depending on prevalent environmental variables. This unpredictability has stimulated the action (Annone and Frutos, 1988). development of predictive models of head blight occurrence that, ifInfection begins when spores are windblown onto successful, would help growers in the selection of control strategies. exposed anthers of wheat heads. The probability of in-As a result of our earlier work, empirical equations for predicting fection is greater when the anthers are exposed for a head blight incidence were developed at Pergamino INTA Experilonger period of time. This period with exposed anthers ment Center (Lat., 33؇ 56S), associating temperature and moisture lasts approximately 30 d in a commercial wheat field variables with mean disease observations from many wheat cultivars. (Reis, 1987). The critical period for infection extends In the current study our objective was to validate two of these meteofrom the beginning till the end of flowering, the crop rological based equations developed for Pergamino to predict wheat being less susceptible when grain filling starts. The anhead blight incidence and severity at Zavalla (Lat., 33؇ 1S) and Olithers constitute an important nutritional substrate for veros (Lat., 32؇ 33S) in moderately susceptible to susceptible cultivars the fungus, enhancing its rapid growth towards the ovafor the years 1993 to 1995. Even though the t-test determined nonsignificant differences between mean observed disease values versus ries and developed grains. Under proper environmental predicted values, a graphic method and a deviation examination conditions, the fungus grows into the kernels, glumes, or showed an underestimation at high disease levels. Simple analyses of other head parts (McMullen et al., 1997), thus producing sensitivity were able to detect the improvement in incidence and flower abortion early in the season and shriveled grain severity goodness of fit estimations that resulted from increasing the later. The pathogen overwinters in cereal residues and maximum temperature threshold and the heat accumulation defining secondary hosts until it is hydrated the next growing the length of the wheat critical period for infection. This study showed season, causing it to produce perithecia which release that meteorological based empirical equations developed for Pergamspores to infect another crop.ino can be useful for predicting disease intensity at more northern According to Galich and Galich (1996), Argentine locations in the Pampas region, making only a few changes in temperawheat cultivars have demonstrated two degrees of sensiture thresholds.

Giberela do trigo: aspectos epidemiológicos e modelos de previsão

“…Esse modelo preditivo foi validado e ajustado para o norte da região pampeana (Moschini et al, 2001). Nesta, foram desenvolvidas duas equações que expressam a relação entre incidência e a severidade para cultivares suscetíveis e moderadamente suscetíveis, calculando a severidade para os dois grupos de cultivares com diferente resistência.…”

Micotoxinas en harinas derivadas de trigo y soja detectadas por prueba de Elisa

“…Esto podría deberse a su susceptibilidad al hongo combinada con el ambiente presente, durante el ciclo de cultivo, lo que resultó favorable para la infección y el desarrollo de la enfermedad, según lo reportado por Moschini et al (2001) …”

CARACTERIZACIÓN DE ESPECIES DE Fusarium CAUSANTES DE PUDRICIÓN DE RAÍZ DEL TRIGO EN EL BAJÍO, MÉXICO

“…De manera similar, F. graminearum es la especie predominante causante del tizón de la espiga del trigo en regiones húmedas de EE.UU. (Xu et al, 2008), Argentina (Moschini et al, 2001;Álvarez et al, 2010), China (Gale et al, 2002), Kenia (Muthomi et al, 2007), Irán (Chehri et al, 2010), Australia y sur de Europa (Cook, 2010). La importancia de la detección de esta especie radica en que los granos infectados por F. graminearum pueden contener niveles altos de micotoxinas como tricotecenos y zearalenona, los cuales son altamente dañinos para la salud humana y del ganado (Chelkowski et al, 2000).…”