Effect of some applications on delaying leaf bud opening to protect hazelnuts from spring frost damage

Abstract

Hazelnut is one of the most important agricultural products of Turkey, the number one hazelnut producer and exporter in the world. Spring frost damage is a serious problem for hazelnut, and some years the damage rate can reach up to 100% in some regions. The delay of the opening of leaf buds (bud break) can be very important to avoid spring frost damage. In this study, the effects of applications of 6% kaolin, 10% soybean oil, 10% sunflower oil, white latex paint (mixed with water in a 1:1 ratio), a commercial natural plant antifreeze, and 1% Bordeaux mixture on hazelnut leaf bud opening was investigated under field conditions. After the pollination period was generally finished, applications were performed once a year, on 4 February 2015 and on 3 February 2016. The dates when the ratio of opened buds was more than 50% were recorded as the leaf opening time. Results showed that in 2015, while sunflower oil and white latex paint applications provided a delay of about 4 days, the Bordeaux mixture caused earlier leaf opening compared to the untreated control plot. In 2016, there were no important differences among the applications and control in date of leaf bud opening. These results suggest that sunflower oil and white latex paint applications offer promise for delaying the opening leaf buds. Further studies are planned.