Abstract
Abstract Solar heating (solarisation) of the soil, by means of mulching with transparent polyethylene sheets in the hot season, is used for disease control. The effect of soil solarisation, under different agricultural practices, on incidence of pink-root disease caused by Pyrenochaeta terrestris, and on onion yield and quality was investigated. Onions were seeded in beds of non-infested, either non-solarised or solarised, soil and transplanted into growth containers filled with soil either non-infested or infested with the pink-root pathogen. Growth of plants pre-grown in solarised beds was improved as compared to plants originated from non-infested beds. Plants grown in the infested soil suffered considerably, as expressed in leaf number and length, root quantity and bulbing-process. In a field experiment, early sowing resulted in a higher disease incidence than later sowing. Soil solarisation controlled the disease, improved seedling survival and increased yield in most cases. Delay in harvest to 100% falling tops increased yields and reduced percentage of undersized bulbs. At high plant-population density (170 plants m−2), percentage of small bulbs was higher and rates of double bulbs were lower than at low plant density (90 plants m−2). Soil solarisation resulted in effective disease control and higher yields and facilitated accurate planning of plant population in the field, extension of the growing-season and higher yields of better quality.
Published Version
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