Dynamics ofRhizoctonia solani (black scurf) in successive potato crops

Abstract

The position of plants with Rhizoctonia solani sclerotia (black scurf) on progeny tubers was mapped for an experimental field at Haren where potatoes were grown continuously and in rotation with other crops for five successive years, and for another field at Borgercompagnie with a 1:2 frequency of potatoes during three potato crops. Initially, the distribution of plants with black scuff on both fields was rather dense and homogeneous. In the following years the distribution became heterogeneous and patchy. The local decline of R. solani AG 3 (the common potato pathogen) in Haren was apparently caused by an unknown factor selectively suppressing R. solani AG 3, while simultaneously R. solani AG 5 increased in mass. This AG 5 type proved to be an inferior competitor of AG 3 on the potato plant in a laboratory experiment. The specific R. solani antagonist Verticillium biguttatum did not play a role. A similar factor could have reduced the formation of black scurf in the experimental field at Borgercompagnie, where V. biguttatum was also too infrequent to account for the decline. R. solani AG 5 was not present here and could not indicate the presence of a selective factor against AG 3.

Impact of Continuous Cropping of Lettuce on the Disease Dynamics of Bottom Rot and Genotypic Diversity of Rhizoctonia solani AG 1-IB

“…The patchy nature of Rhizoctonia diseases in the field is well documented for black scurf in potato caused by AG 3 (Jager and Velvis 1995), root rot in sugar beet caused by AG 2‐2IIIb (Hyakumachi et al. 1990), R. solani AG 8 in cereals (MacNish 1985) and R. solani AG 2 in tulips (Schneider et al.…”

Biological destruction of conidia ofVerticillium biguttatum

“…Biological control of R. soIani with V. biguttatum applied at planting was often less effective in slightly acid sandy soils than in neutral marine loams Velvis, 1985, 1986;Jager et al, 1991). The density of V. biguttatum on subterranean plant parts, in the soil and on tuber-borne sclerotia was also very low in two sandy soils, even after inoculation in spring (Jager and Velvis, 1995). This may be caused by differences in activity of predators, parasites and/or other detrimental factors like fungicides applied to soil.…”

Rhizoctonia solanidisease suppression: addition of keratin-rich soil amendment leads to functional shifts in soil microbial communities

“…Take-all decline is defined as the spontaneous reduction in the incidence and severity of the disease and increase in yield occurring with continuous monoculture of the host crop following a severe attack of the disease (Schlatter et al, 2017). Also, for R. solani-induced diseases a decline has been reported in both field and pot experiments for several crops, i.e., wheat (Lucas et al, 1993;Mazzola & Gu, 2002;Roget, 1995;Wiseman et al, 1996), sugar beet (Expósito, 2017;Hyakumachi et al, 1990;Sayama et al, 2001), radish (Chern & Ko, 1989;Chet & Baker, 1980;Henis et al, 1978), potato (Jager & Velvis, 1995;Velvis et al, 1989) and cauliflower (Davik & Sundheim, 1984;Postma et al, 2010). The second approach to stimulate disease suppression requires the addition of organic amendments into soils.…”