Forecasting, epidemiology and control of powdery mildew [Erisyphe betae] in sugar beet [in the United Kingdom]
1996
Asher, M.J.C. | Williams, G.E. (IACR-Broom's Barn, Bury St Edmunds (UK))
The national area infected with powdery mildew at the end of August each year in the UK is strongly negatively correlated (r = -0.91) with the total number of days with a ground frost in February and March. The disease never developed before early August in field plots artificially inoculated by transplanting infected plants from the glasshouse from early July. However, the subsequent rate of epidemic progress was more rapid in plots inoculated early. Disease development in naturally infected plots of a common susceptible cultivar in each of the years 1989-93 fitted a common logistic model with different rate parameters. Over all years the rate of disease progress was most closely correlated (negatively) with the amount (r = -0.98) and frequency (r = -0.97) of rainfall. The average yield increase from controlling powdery mildew with a single sulphur spray in trials in 1990-92 was 8 per cent or 5.8 adjusted tonnes per hectare, giving an estimated increase in production in the UK in 1995 of 280000 adjusted tonnes of beet.
显示更多 [+] 显示较少 [-]