Preparation Method and Usage Techniques of Fruit Tree Trunk Whitewash

Applying whitewash to fruit tree trunks can defend against freeze damage, prevent pests from overwintering on the trunk, and kill diseases and pests on the trunk. Because the purposes differ, the preparation methods of whitewash also differ.

1. Main purpose: freeze prevention. Fruit trees such as fragrant pear, apricot, plum, peach, and stone-fruit types are prone to freeze damage, especially in low-lying areas. Applying whitewash to the trunk every winter is an effective freeze-prevention method. In early November, for 4-5 year old young trees that cannot be buried with soil, apply whitewash to the main trunk, preferably up to the main trunk fork. Whitening for cold protection on young trees can ease the temperature difference between the sunny and shady sides of the trunk, giving a relatively good cold-protection effect, and it can be applied before the soil freezes. The whitewash formula is: salt 0.5 kg, quicklime 6 kg, clear water 15 kg, plus an appropriate amount of adhesive and residue from lime sulfur mixture, mixed into a paste, applied all over the young tree branches and trunks and old trees after scraping the bark; from late November to late December, brush the trunk white. On sunny days it can reflect sunlight, reduce absorbed solar heat, narrow the temperature difference before and after freeze damage and the day-night temperature difference on the trunk, and can defend against freeze damage.

2. Main purpose: preventing diseases and pests from overwintering on the trunk. Whitewash formula: quicklime 10 kg, salt 1 kg, lime sulfur mixture stock solution 1 kg, water 40 kg, plus cooking oil 0.2 kg. From late November to mid-February of the following year, scrape off the old bark on the main trunk and main branches. Pear trees should be scraped heavily; peach, plum, and apricot are prone to gumming, so scrape cautiously. For plum, pear, and peach trees over 10 years old, the trunk has many cracked and lifted bark areas, which become overwintering sites for pathogens and pests. Brushing with whitewash can prevent pests from invading the bark to lay eggs and pupate, and kill pests and pathogens attached to the bark, while also helping prevent freezing and sunscald.

Usage precautions

1. Fruit tree whitewash should be mixed and used immediately; it must not be stored for long.

2. When using, stir the whitewash thoroughly so it can be brushed evenly and adhere tightly to the trunk.

3. Before using whitewash, it is best to first use pruning shears on the trees of orchards and roadside trees to remove diseased branches, weak branches, aged branches, and overly dense branches, then collect them and burn them, and wrap cracked and freeze-cracked areas with plastic film.

4. During careful inspection, if pests are found to have bored into the branches or trunk, use cotton soaked in pesticide to kill the pests before carrying out the whitewashing treatment.

5. When brushing, dip a brush or straw bundle into the whitewash, choose a sunny day, and evenly whitewash the base of the main branches and the main trunk. The whitewashing height is mainly 1-1.5 m above the ground. If old trees have been renewed by heavy pruning to expose the framework, to prevent sun exposure, the whitewashing position should be raised, or the whole plant should be whitewashed. Hairaguli