growers-advice-fight-against-blight-advice-for-growers-of-organic-crops
Integrated measures to avoid, prevent or delay the onset of blight (Phytophthora infestans) in organically produced potatoes
The scope for fungicide use is severely limited in organic crops. This means that cultural methods of control are the foundation for blight management. This report emphasises on the integration of different cultural measures. Protectant copper compounds are currently the only fungicide used in organic potato production for blight control under high risk situations before infection takes place. However copper should still be used if blight is detected in the crop to try to slow down further spread. The report provides useful advices on the circumstances under which registered protectant chemical compounds can be used and the protocol to be followed. Protectant copper compounds were due to be prohibited in the EU from March 2002, but removal has been delayed until effective control methods are developed, though the uses of these compounds were progressively restricted.
Cultural methods that were addressed included variety choice based on NIAB (National Institute of Agricultural Botany, Cambridge) ratings, seed quality and management, site characteristics, planting date and planting, crop nutrition, irrigation, crop infection, defoliation, crop hygiene and observations. Until the end of 2005, use of copper is restricted to a maximum of 8kg of elemental copper/ha/year, then 6kg of elemental copper/ha/year thereafter, with the aim of completely phasing it out when effective alternative control methods are developed.
