STRIPE RUST, PUCCINIA GLUMARUM, IN CANADA

Abstract

A study was made of the distribution of Puccinia glumarum (Schm.) Erikss. and Henn. in Canada, its specialization, host range, and reaction to environmental conditions. Unlike Puccinia graminis Pers., this rust has a limited distribution, being confined to British Columbia, Alberta, and the western half of Saskatchewan. The natural hosts include a number of native grasses, particularly Hordeum jubatum L. and certain species of Agropyron, Elymus, and Bromus. Wheat and barley also become infected although to a rather limited extent: Stripe rust collected on the above-mentioned hosts has been studied in the greenhouse and has in all cases shown ability to attack wheat varieties. In all instances where identification of physiologic forms was carried out the rust strains were classified as either form 8 or form 13 of wheat stripe rust, the latter form being the more common. The fact that the present authors have collected known physiologic forms of wheat stripe rust on species of Hordeum, Elymus and Agropyron, and have shown that forms 4, 6, 8 and 13 can attack seedling plants of Hordeum, Agropyron, and Elymus species throw a doubt on the existence of the Hordei, Elymi, and Agropyri varieties created by Eriksson.Greenhouse studies showed that P glumarum is extremely sensitive to environmental conditions, particularly temperature. The optimum for uredospore germination is 10° to 12 °C., and for rust development 13° to 16 °C. Varieties susceptible at from 10° to 16 °C. developed resistance at higher temperatures, becoming extremely resistant at 25 °C. On account of the sensitiveness of this rust to high temperatures it seems improbable that it will ever become thoroughly established in Manitoba and Saskatchewan, as in these two provinces the summer temperature is probably too high to permit its development.

Chilling Stress—The Key Predisposing Factor for Causing Alternaria alternata Infection and Leading to Cotton (Gossypium hirsutum L.) Leaf Senescence

“…The presented results were also consistent with previous studies performed on other plant diseases. Such as, it was reported that pre-inoculation temperature at 12.9°C often increased susceptibility in wheat to stripe rust [41]. It was also reported that tobacco callus cultures inoculated with tobacco mosaic virus (TMV) and soybean callus cultures inoculated with southern bean mosaic virus (SBMV) revealed a higher rate of virus synthesis held for 4 days at 10°C than those continuously maintained at 24°C [42].…”

The effect of pre- and post-inoculation temperature on resistance in certain cultivars of poplar to races of Melampsora larici-populina kleb.

“…. Similarly wheat plants susceptible to stripe rust at 12 .9°C became resistant when exposed to a temperature of 25 .3°C (NEWTON & JOHNSON, 1936) . SHARP (1962) demonstrated that, depending on the cultivar, wheat plants grown at 24°C before inoculation with Puccinia striiformis (syn .…”

Stripe rust reaction of 28 Canadian wheat cultivars1

“…In subsequent years, it was found in British Columbia, southern Alberta, and western Saskatchewan but was not found during that time in Manitoba or eastern Saskatchewan (Newton and Johnson 1936). The main area of concern for stripe rust in Canada has been southern Alberta, where it is an annual production problem.…”

“…The disease was particularly devastating in Alberta in 2005, when severities of up to 100%, based on a modified Cobb's scale (Peterson et al 1948), were observed in some wheat nurseries, resulting in premature ripening of portions of the heads and prolific production of urediniospores between kernels and glumes (McCallum et al 2006). Although it was demonstrated that the rust can overwinter in Alberta (Conner et al 1988), the primary source of inoculum was thought to be windborne urediniospores from the adjoining states of Montana, Idaho, and Washington (Newton and Johnson 1936). Stripe rust was not reported in the eastern Prairie regions of Manitoba or Saskatchewan in Canada until 2000 (Fetch and McCallum 2001).…”