The effect of post‐harvest storage conditions on the development of black dot (Colletotrichum coccodes) on potato in crops grown for different durations

Abstract

The effects of post-harvest curing and storage temperature on severity of black dot, caused by Colletotrichum coccodes, were investigated for potato crops grown for different crop durations (days from 50% emergence to harvest) in soils that posed a low, medium and high risk of disease. In field trials over four growing seasons , black dot severity at harvest increased with increasing crop duration, within the range 103-146 days from 50% emergence to harvest (P < 0.05). In field trials over three growing seasons , black dot severity on tubers at harvest increased significantly with increasing soil inoculum in each year, within the range 43-4787 pg C. coccodes DNA/g soil (P < 0.05). Storage trials were conducted to measure the influence of accumulated post-harvest temperature on black dot. In 2005, no difference in black dot severity was observed on tubers stored for 20 weeks at 2.5 and 3.5°C. In 2006 (but not 2007), increasing the duration of curing after harvest from 4 to 14 days increased black dot severity on tubers from 8.9 to 11.2% (P < 0.01) in long duration crops (>131 days after 50% emergence) grown under high (>1000 pg C. coccodes DNA/g soil) soil inoculum. The number of days of curing did not affect disease severity for shorter duration crops grown at high soil inoculum, or on crops grown at medium or low (100-1000 and <100 pg C. coccodes DNA/g soil, respectively) soil inoculum concentrations. Soil inoculum and crop duration together provided a reasonable prediction of black dot severity at harvest and after a 20-week storage period.

Most Colletotrichum species associated with tree tomato (Solanum betaceum) and mango (Mangifera indica) crops are not host‐specific

“…Colletotrichum spp. are pre‐ and postharvest pathogens and thus cause high economic losses that may reach up to 50% of the total production (Ali et al ., ; Bhutia et al ., ; Peters et al ., ). Significant research efforts have focused on understanding the physiology, host–pathogen interactions, and evolution of these plant pathogenic species in order to generate accurate control strategies (Cai et al ., ; Soltani et al ., ; Rahman et al ., ).…”

Influence of abiotic factors, inoculum source, and cultivar susceptibility on the potato tuber blemish diseases black dot (Colletotrichum coccodes) and silver scurf (Helminthosporium solani)

“…Altogether, the factors of soil inoculum, weather conditions, and cultivar susceptibility could be used in a risk assessment scheme. Because black dot and silver scurf may progress during storage (Hide et al, 1994; Peters et al, 2016; Rodriguez et al, 1996), the early distribution of tuber stocks with high risk should be prioritized.…”

Applications of New Breeding Technologies for Potato Improvement

“…Soil-transmitted black dot, caused by Colletotrichum coccodes imparts brown necrotic lesions/stains on tuber skin and promotes their rapid decay (Brierley et al, 2015 ). Storage temperature and durations are two important factors determining the tuber susceptibility to black dot disease and could be managed to prevent the quality losses in potato (Peters et al, 2016 ). The tuber harvesting date also influences tuber quality during the long-term storage.…”