Bagging and Unbagging Peach Fruit: Proper Timing and Classification Are Key

Editor's note: Fruit bagging can effectively reduce fruit cracking and mechanical damage, improve the color of the fruit surface, greatly enhance the fruit's marketability, and also prevent and control pests and diseases, reduce pesticide use, and lower pesticide residues. To help farmer friends master this technique, we have specially invited relevant experts to introduce bagging techniques for peach, kiwifruit, citrus, pear, grape, and other fruits. In this issue, we introduce kiwifruit and peach bagging techniques.

The kiwifruit bagging technical measures are: bag selection, fruit thinning, fruit setting, pesticide spraying, bagging, protection, bag removal.

For paper bag selection, single-layer cream-yellow thin waxed wood pulp paper bags are preferred, 15-18 cm long, 11-13 cm wide, with a slit in the middle of the upper opening, wire added on one side, and a 2-4 cm opening at one corner of the bottom; the paper bags should be waterproof, breathable, and tough.

Fruit thinning and fruit setting: For kiwifruit pruned with short shoots during the dormant period, retain as many fruiting branches as possible, leave 3-4 fruits per fruiting branch, and remove excess fruits. For kiwifruit pruned with long shoots, remove the fruits on weaker fruiting branches at the base of the fruiting mother branch, and leave 2-3 fruits on the remaining fruiting branches. If the middle part of the fruiting mother branch cannot normally produce fruiting branches, 3-4 fruits can be left on sparse fruiting branches. For weaker or injured fruiting mother branches, leave fewer fruits or no fruits as appropriate. Promptly remove diseased and pest-damaged fruits, deformed fruits, abrasion-marked fruits, and poorly nourished fruits. When thinning fruits, work from the inside outward and from weak branches to strong branches. For young orchard trees, according to the strength of the fruiting mother branch, leave 2-3 fruiting branches per fruiting mother branch, and leave 2-3 fruits per fruiting branch.

Pesticide spraying for control: Before bagging the fruits, spray the whole orchard once with an insecticide and fungicide, such as 20% fenpropathrin 2500-fold solution, 18% Fengsha 2000-fold, or 2000-fold Green Kung Fu, and broad-spectrum fungicides such as thiophanate-methyl or carbendazim, to control pests such as scarab beetles, small longhorn beetles, stink bugs, and scale insects, and to prevent and control other diseases such as fruit soft rot and gray mold. The use of highly toxic and high-residue pesticides is prohibited, and the use of plant growth regulators should be controlled.

Bagging time: Kiwifruit fruit enlarges fastest 40 days after flowering, and the bagging time is about late June, which is more suitable. But it must be chosen after pesticide spraying. On days with strong sun exposure, the suitable times are 8-12 a.m. and 3-7 p.m.

Bagging method: When bagging, use one hand to open the bag mouth, and from bottom to top put the intact young fruit into the fruit bag; use the other hand to fold the bag mouth from the slit into even pleats, and use the wire on the side of the bag to tie the pleats tightly. Single fruits growing on fruiting branches can be tied directly to the fruiting branch where the fruit is borne; clustered fruits should be tied directly to the fruit stalk, with the folded bag pleats cushioned against the fruit stalk, and the fruit stalk must not be twisted or injured by tying. Check whether the lower part of the fruit bag has an opening; if the bottom of the bag is completely sealed, use scissors to cut a 2-4 cm opening. The upper opening should be sealed tightly. When bagging, work from the inside outward, with gentle movements, and promptly secure drooping or upright bagged branches to prevent them from being swayed by strong winds.

Management after bagging: After bagging, strengthen fertilizer and water management. After bagging, root application of topdressing can be done, and foliar fertilizer can be sprayed; pay attention to irrigation and drainage. Strengthen summer pruning, cultivate sufficient nutrient branches, and protect the leaf canopy layer. Strengthen integrated pest and disease control. Promptly stabilize trellis materials, promptly tie branches, and protect against wind to secure the trees.

Bag removal and harvest: After the fruits enter the ripening stage, the bags can be removed and the fruits harvested. Remove the paper bags 3-5 days before harvesting. For fruit bags tied to fruiting branches, first support the bottom of the fruit bag, loosen the tying wire of the fruit bag, rotate the fruit bag, and pick the fruit together with the fruit bag. For those tied to the fruit stalk, support the bottom of the fruit bag and rotate it, and pick the fruit together with the fruit bag. Gently untie and remove the bag from the harvested fruit, then grade them.