Managing crop losses from foliar diseases with fungicides, rotation, and tillage in the Saskatchewan Parkland

Abstract

. 2000. Managing crop losses from foliar diseases with fungicides, rotation, and tillage in the Saskatchewan Parkland. Can. J. Plant Sci. 80: 169-175. The effects of three tillage systems, three crop rotations, and fungicide applications were evaluated on diseases of barley, wheat, canola and pea at Melfort, SK, from 1994 to 1998. During these years, reduced tillage did not increase crop losses due to diseases. Four-year rotations with higher proportions of broad-leaved crops and more crop diversity (i.e., canola, pea, flax, and barley) had higher yields than rotations with fewer broad-leaved crops and less crop diversity (i.e., canola, wheat, barley, and barley). However, these rotations did not influence the severity of septoria leaf blotch of wheat, net blotch of barley, the incidence of sclerotinia stem rot and blackleg of canola, or the severity of mycosphaerella blight of pea. Interplot interference may have been a factor influencing some diseases in plots, as the size was only 270 m 2 . Fungicide application of propiconazole on Harrington barley decreased foliar disease severity and increased yield by 23%, seed weight by 13%, and kernel plumpness by 25%. Application of azoxystrobin decreased foliar disease and increased pea yield 29% and seed weight by 7% for the pea cultivars Express and Highlight. Foliar disease severity on AC Taber wheat was reduced by application of propiconazole in 2 of 4 yr, but the yield response was very inconsistent. Similarly, AC Excel canola had inconsistent disease and yield response to applications of propiconazole and benomyl, but levels of sclerotinia stem rot and blackleg were very low in all years. These results indicate that reduced tillage will not result in significantly higher levels of disease that require fungicide inputs to maintain yield. Moving from cereal-based rotations to more diverse, broad-leaved based rotations improves the yield of cereals. However, regardless of tillage or rotation, higher yields may be obtained in barley and pea with fungicides for control of leaf spot disease in susceptible cultivars. . Nous avons évalué de 1994 à 1998 les effets de trois régimes de travail du sol, de trois rotations des cultures et des traitements fongicides sur les maladies foliaires de l'orge, du blé, du colza canola et du pois à Melfort en Saskatchewan. Durant ces années, la pratique du travail réduit du sol n'a pas accru les pertes de rendement attribuables aux maladies. Les rotations de 4 ans comprenant une plus grande proportion de cultures dicotylédones et une plus large diversité botanique, p. ex., colza canola, pois, lin et orge, fournissaient des rendements plus élevés que les rotations moins diversifiées et moins bien pourvues en dicotylédones, p. ex. canola, blé, orge et orge. Toutefois, elles n'avaient pas d'impact sur la gravité de la septoriose des feuilles, de la rayure réticulée de l'orge, de la brûlure ascochytique du pois ni sur l'incidence de la pourriture scléro-tique de la tige ou de la jambe noire chez le colza canola. Les contaminations interpar...

Impact of crop sequence decisions in the Saskatchewan Parkland

“…In an earlier study at this location, Bailey et al (2000) indicated that fungicides effectively controlled barley and pea diseases and reduced yield losses. However, fungicides were less effective for wheat and canola diseases.…”

The impact of fungicide and herbicide timing on foliar disease severity, and barley productivity and quality

“…is high (Tekauz 2003;Turkington et al 2004Turkington et al , 2011Turkington et al , 2012Kutcher et al 2011). Yield losses of up to 20% from these diseases have been reported, while similar yield increases from fungicide have also occurred (Skoropad 1960;Buchannon and Wallace 1962;McDonald and Buchannon 1964;Bailey et al 2000;Ghazvini and Tekauz 2004;Turkington et al 2004;Kutcher et al 2011;Turkington et al 2012). The most important negative impact of leaf diseases is the destruction of photosynthetic leaf area, especially in the upper barley canopy.…”

Insights into fighting against blackleg disease of Brassica napus in Canada

“…The timing of fungicide application is crucial in blackleg control as the fungicides are not able to control the disease once the pathogen has reached the stem (Steed et al 2007;Peng et al 2012;Liu 2014). Although foliar fungicides have been shown to reduce disease severity and increase yield in blackleg susceptible canola varieties, there is no economic benefit of using fungicide in resistant canola varieties (Bailey et al 2000;Liu 2014). Reduction of disease with yield gain on MR or R-rated cultivars can only be achieved when there is severe erosion of resistance in a cultivar due to pathogen shifts (from Avr to avr) (Liu 2014).…”