Brown spot of Rheum officinale in Indonesia with special reference to the variation in conidia of the causal fungus

Effects of temperature on germination and hyphal growth from conidia of Ramularia rhei and Ascochyta rhei, causing spot diseases of rhubarb (Rheum rhaponticum)

“…The optimal temperature (around 20°C) for R. rhei germination and germ‐tube growth was similar to that for other Ramularia species (Hestbjerg et al ., 1994; Kumar & Joshi, 1995; Francis, 2000). The optimal temperature for conidial germination of A. rhei was around 22–27°C, similar to that reported by Djiwanti et al . (1994) on Rheum officinale .…”

“…(Hestbjerg et al, 1994;Kumar & Joshi, 1995;Francis, 2000). The optimal temperature for conidial germination of A. rhei was around 22-27°C, similar to that reported by Djiwanti et al (1994) on Rheum officinale. Initially, the germ tube of R. rhei developed faster than that of A. rhei, possibly because of differences in their conidial sizes.…”

“…Since spot disease is not yet a problem of economic importance to rhubarb production in Europe, little research and investigation have been conducted on its biology and epidemiology. Spot disease caused by A. rhei was also reported in Rheum officinale in Indonesia ( Djiwanti et al ., 1994).…”

“…Spot disease caused by R. rhei was mostly observed at temperatures of 18–23°C in the coastal region of British Columbia, Canada (Ormrod et al ., 1985). On R. officinale , spot disease caused by A. rhei in Indonesia was prevalent only in the hotter season (Djiwanti et al ., 1994).…”