Life‐history of Phragmidium rubi‐idaei on red raspberry in the United Kingdom

Abstract

Phragmidium rubi‐idaei produced five spore stages on red raspberry and overwintered as teliospores adhering to canes. In the field spermagonia appeared in a single flush in early summer on leaves of the primocanes (first‐year canes) and on leaves of the lateral shoots of fruiting canes, and were followed by aecia, uredinia and telia. Aecia and uredinia occasionally appeared on petioles and sepals and uredinia on drupelets of mature fruit. Lesions caused by aecia and uredinia on the bases of primocanes did not become cankerous in the following fruiting year. Necroses associated with large aecia produced a shot‐hole effect and leaflets heavily affected by either aecia, uredinia or telia abscissed prematurely. The sequence of spore stages on pot‐grown plants inoculated with mature overwintered teliospores took 60 days to the reappearance of telia. The rate of development of uredinia and associated necroses was faster on younger than on older leaves but the cumulative spore yield was not significantly different. Optimum temperature for germination of urediniospores in vitro (18.4–20.9°C) was higher than for mature teliospores (14.6–18.4°C). Light inhibited germination of both types of spores. Teliospore germination was inhibited by wavelengths of 590–750 nm, but this was partially reversible under other light conditions. A reversible inhibition of basidiospore formation was also observed under shorter wavelengths.

Resistance to cane spot (Elsinoë veneta) in the red raspberry and its relationship to resistance to yellow rust (Phragmidium rubi-idaei)

“…The latter instance is different from cane spot and rust, because the two pathogens occupy the same ecological niche on the raspberry canes, whereas cane spot is predominately a disease of the canes and yellow rust is predominantly a disease of the leaves, where gene H has no known effect. It may be significant that both P. rubi-idaei and E. veneta can infect only young leaves (Converse, 1966 ;Anthony, Shattock & Williamson, 1985) . There is no evidence to indicate whether these situations are due to close linkage between gene H and genes for resistance or susceptibility to the various diseases, or to pleiotropic effects of gene H, possibly on an epidermal characteristic .…”

Pathogenicity of Phragmidium violaceum isolates on European blackberry clones and on leaves of different ages

“…Once leaves expand to a certain proportion of their final size, the density or number of uredinia diminishes as the leaf ages for a wide range of Uredinales species, including Pv (Schein, 1965; Sharma et al. , 1980; Anthony et al. , 1985; Savary, 1987; Coutinho et al.…”

Resistance to cane and foliar diseases in red raspberry (Rubus idaeus) and related species

“…This macrocyclic autoecious rust (Phragmidium rubi-idaei) attacks only red raspberries and came to prominence in the last 20 years on cvs Glen Clova and Malting Delight which are highly susceptible (Anthony et al ., 1983(Anthony et al ., , 1985a . Several kinds of resistance have been identified from experiments in which use was either made of `bait' plants exposed in uniformly infected commercial plantations, or of controlled inoculation procedures with bulked mass isolates of urediniospores in glasshouses .…”