I sometimes have what I call a "trivial memory". In other words, little bits of data get stuck in my mind and I do understand the concept, but unless it's important to me at that time, I really don't study a topic deeply and just keep that little bit in my memory.
I had remembered that glossy leaved roses were more susceptible to many of the races of black spot, but that's all I remembered. I did a quick Google search and found this article:
http://hortsci.ashspublication...
This is the most important paragraph:
Rose cultivars can vary significantly in their susceptibility to diseases incited by fungal pathogens (Castledine et al., 1981; Palmer et al., 1966; Reddy et al., 1992; von Malek and Debner, 1998; Xue and Davidson, 1998). Interestingly, Genders (1965) reported that glossy leaved varieties of rose were more troubled by the blackspot pathogen Diplocarpon rosae than the less glossy leaved varieties. Because the degree of glossiness or glaucousness of a leaf surface is the result of the amount of crystalline structure in cuticular wax deposits (Jenks and Ashworth, 1999), Genders’ findings reveal that waxes of the rose cuticle may play an important role in rose pathogen resistance. Moreover, numerous studies in other plant systems show how diversity in the structure and composition of cuticular waxes can be associated with plant protection against fungal pathogens, sometimes in complex ways and often unique to the specific plant–pathogen interaction (Jenks and Ashworth, 1999). Recent studies also suggest that, besides waxes, the cutin component of the plant cuticle may also influence plant susceptibility to disease (Jenks et al., 1994; Xiao et al., 2004). To date, however, the exact function of either cutin or waxes in rose pathogen resistance is unclear. A detailed analysis of the cutin monomers and waxes of rose cuticle, along with an examination of disease resistance, in five important rose cultivars is reported here.
I really haven't searched any of my notes. I am pooped
I finished pruning all of the roses. The deer fence is up. Tomorrow, I'll be weeding, composting, feeding and mulching. Starting Thursday, it is supposed to rain every day for a week.
