Effects of soil temperature and moisture on stem canker (Rhizoctonia solani) disease of potatoes

Summary Potato seed pieces bearing one sprout were inoculated with cultures ofRhizoctonia solani, planted in pots of compost at 45, 60, 75 or 90% water holding capacity (whc) and incubated at 5, 10 or 15 °C. Shoots emerged after 2–3 wk at 15°C, 3–4 wk at 10 °C and after 9–11 wk at 5 °C and stem canker recorded after emergence, was severe at 10 and 15 °C but slight at 5 °C. Soil moisture had less effect on emergence but stem canker was more severe in dry (45 % whc) than moist soils (75 and 90 % whc). The relationship between time of shoot emergence and stem canker severity is discussed.