The susceptibility of tubers of potato cultivars to black dot (Colletotrichum coccodes (Walk.) Hughes)

Abstract

In experiments with commercial seed of different cultivars at Rothamsted and Woburn, Bedfordshire in 1985 -88 the severity of black dot on daughter tubers at harvest differed between cultivars. The disease was most severe on DCsirCe tubers. Amounts of disease were similar at both sites in 1986 -88 but in 1985 it was more severe at Woburn than at Rothamsted.Disease-free seed of 12 (1987) or 15 (1 988) cultivars were planted in experiments at Rothamsted (inoculated with Colletotrichum coccodes or not) and at Mepal, Cambridgeshire (not inoculated) and black dot assessed at harvest in October 1987 and in September and October 1988. There were significant differences in the amount of disease on different cultivars and the order of severity was similar at the two sites, on the two harvest dates in 1988 and in both years. DCsirke, Maris Piper, Maris Peer and Record were amongst those cultivars severely affected whereas Cara, Pentland Crown and Romano were least affected.Skin discoloration caused by black dot was more noticeable on white-skinned than red-skinned cultivars and was severe on the Dutch cultivars Estima, Marfona, SantC and Wilja.

Colonization of roots, stolons, tubers and stems of various potato (Solanum tuberosum) cultivars by the black‐dot fungus Colletotrichum coccodes

“…The differences observed in the development and effects of black dot among cultivars outlined the variation for susceptibility of potato genotypes to the disease already recognized in field experiments and disease surveys (Harrison, 1963;Thirumalachar, 1967;Read, 1991;Andrivon et al, 1997), and provided indications about the reasons for this variation. For instance, while the most obvious effect of the fungus was an early reduction in the number of stolons and tubers in Bintje, infection by C. coccodes did not affect the development of subterranean organs in Roseval.…”

“…Most reports have focused on specificity at the genus or family levels (Chesters & Hornby, 1965;Mordue, 1967;Andersen & Walker, 1985;Maas & Howard, 1985;Raid & Pennypacker, 1987;Gotlieb et al, 1987), and a few studies have been devoted to comparisons of the pathogenicity of different isolates to a single Plant Pathology (1998) 47, 440-445 ᮊ 1998 BSPP potato cultivar (Barkdoll et al, 1990;Barkdoll & Davis, 1992) and to the assessment of the susceptibility of potato cultivars to an unspecified (Thirumalachar, 1967), uncharacterized (Read, 1991), or natural, uncontrolled inoculum (Andrivon et al, 1997). However, data on the reaction of a set of cultivars to different, well-characterized isolates of the fungus are lacking.…”

Carnimonas nigrificans gen. nov., sp. nov., a bacterial causative agent for black spot formation on cured meat products

“…Colletotrichum coccodes (Wallr. ) Hughes produces black spot tubers of potato (Read, 1991), whereas Alternaria alternata is the causal agent of black spot disease on mango fruits (Prusky et al, 1993). Within bacteria, pigmentation is a well-known phenomenon.…”

Treatment of seed potatoes with prochloraz for simultaneous control of silver scurf and black dot on progeny tubers

“…1989. Although soil factors are known to affect black dot development (Read, 1991), soil inoculum of C. coccodes evidently did not play a role since the present experiments and those of Read & Hide (1995) were done in soil free of the pathogen. Initial tuber-borne inoculum of C. coccodes can also be disregarded as a contributing factor since response to prochloraz in the two experiments reported here was essentially the same, notwithstanding differences in degree of seed infection.…”

“…[-i or as 2.5% Octave at 500 (OC500) and 750 (OC750) g product/100 kg seed on the incidence of black dot (A) and silver scurf (B) on progeny tubers at harvest in the Northern Province, Bars with the same lelter do not differ statistically significant according to Tukey's multiple range test (P=0.05). in response were due to different cultivars, considering that cvs D6sir6e, Estima and King Edward used by Hide et al (1987) and Read & Hide (1995), and cvs BP1 and UTD used here are all susceptible to black dot (Thirumalachar, 1967: Read, 1991: Denner & Marais. 1989.…”