Effects of the period of application of K-phosphite on residues on apple fruits

Summary in the original language of the document

K-phosphite is very efficient against several plant diseases. Nevertheless at the moment there is no official
registration in Europe as a plant protection material. In conventional winegrowing K-phosphite is used in
different countries to regulate the main disease ‘Plasmopora viticola’ under the disguise of a foliar fertilizer or
a plant strengthener. In organic apple production only a few fungicides to regulate scab are available. In
addition, copper products are limited by European and national legislations. The discussion about Kphosphite
for organic farming points always at the problem of synthetic residues on the edible parts of the
vegetables. The aim of this field-trial carried out during the season of 2005 was to assess the residues on
apples after applications of K-phosphite at different moments during the season. The results show that
treatments before blossom leave no residues wheras treatments after blossom lead to the same level of
residues independently of the period of application.