Abstract:
The use of some chemicals including vitamins C and E, copper hydroxide, gibberellic acid, pinolene, urea, captan, ethephon, chlormequat chloride and paclobutrazol for early spring frost protection of cherry and peach trees was studied. Applications before frost of urea, copper hydroxide and a mix of glycerine or captan + vitamins C and E reduced the damage to flowers (at rates up to 40?60%), while application of gibberellic acid in combination with captan and pinoline 6 h after frost, reduced the damage by 40?50%. Ethephon delayed the bloom time of peach and cherry trees for about a week. Placing 2 sprinkler heads (200 L/h) on the tree at 40 or 280 cm height raised the temperatures 2.0 and 1.0?1.5�C, respectively.