The control of apple scab and powdery mildew is a challenge for organic fruit growing. Bicarbonate salts are already consecrated in reducing the attack of scab and powdery mildew in organic apple culture. In the current study the following seven substances (Potasium bicarbonate, Wettable sulphur, Potassium bicarbonate + Wettable sulphur, Potassium silicate, Sodium bicarbonate, Calcium bicarbonate, Cooper ammoniac-phosphate) were used on six apple cultivars (‘Elstar’, ‘Pinova’, ‘Golden Delicious’, ‘Luna’, ‘Topaz’ and ‘Sirius’) to detect the effect of these on scab and powdery mildew. The experiments were carried out during 2013-2016 at Steluța LTD, Cluj-Napoca, N.W. Romania. It was a bifactorial experiment, set up in randomised blocks. The trees were planted in 2010 at a density of 3333 trees/ha. Depending of the year a number of 22-24 treatments were made annually after each rain. As a conclusion the combination Potassium bicarbonate + Wettable sulphur significantly reduced the attack degree of scab and powdery mildew on leaves and fruits and increased the yield of the scab-susceptible and scab resistant cultivars. Good results were obtained in case of treatment with Potassium bicarbonate or mixture of Potassium bicarbonate with potassium silicate and Cooper ammonium phosphate. Cooper ammonium phosphate was administrated in ten times lower rate as the other cooper based products, thus pollution and costs go down ten times too, one can conclude that this chemical formulation surpasses by far the acknowledged copper-based products. The treatments with the products used in the experiments did not register symptoms of phytotoxicity on leaves or flowers.

 

 

This abstract was accepted to be presented at the conference entitled “40 Years of Horticulture Education in Cluj-Napoca†Cluj-Napoca, September 27, 2017, being included in ‘Book of Abstracts’ of this special-anniversary event (http://conference.shst.ro). All accepted papers will be published in a special issue of Notulae Botanicae Horti Agrobotanici Cluj-Napoca journal.