The Best Time and Methods for Bagging Apples: A Detailed Guide

Bagging apples can reduce pesticide residue, prevent contamination of the fruit surface, keep pests and diseases from invading, maintain a smooth, clean fruit surface, and promote apple coloring. If the supporting measures for bagging are inadequate, the fruit will suffer severe black spot disease, many micro-cracks, heavy fruit russeting, and a low marketable rate, resulting in poor orchard returns. Therefore, the key techniques and supporting measures must be mastered. So what time is generally chosen for bagging apples? What methods are there?

I. What time is generally chosen for bagging apples?

When determining the time to bag apples, the best bagging time should be chosen according to different regions and different apple varieties. If bagging is done too early, young fruit is prone to fruit drop and sunscald; if bagging is done too late, the fruit lenticels tend to be large and the surface rough, the apples do not lose their green color completely, and after the bags are removed the color develops slowly, affecting the later color. Therefore, bagging time should be determined accurately by taking multiple factors into account. The following are suitable bagging times for the apple-growing areas of Shaanxi:

1. Yellow-green varieties

To prevent fruit russeting and keep the fruit surface smooth and clean, begin bagging 10-15 days after petal fall.

2. Early-ripening red varieties

Bagging should be done about 30 days after petal fall, that is, at the end of May or the beginning of June. For varieties with heavy physiological fruit drop, bagging should be done after the physiological fruit drop has ended.

3. Late-ripening red varieties

Begin bagging 35-40 days after petal fall. That is, starting bagging from June 5-10 and finishing by June 20 is most suitable, and bagging should be completed by early July at the latest. This is because the June fruit drop has ended, the quality of the fruit is clearly distinguishable, and the degree of lignification of the fruit stalk and the aging of the fruit skin have increased, so the fruit is not easily damaged.

Bagging can be carried out from after the morning dew has dried until evening. However, when the weather is clear, the temperature is relatively high, and the sunlight is strong, the periods of 8:30-11:30 a.m. and 2:30-5:30 p.m. are preferable, as this can prevent sunscald. Note that bagging must not be done when the morning dew has not yet dried, otherwise spots easily appear at the calyx end of the fruit. This is because dew is usually somewhat acidic, which increases the solubility of the pesticide solution on the fruit surface, causing poisoning of the fruit skin and necrosis. Likewise, bagging must not be done after spraying while the pesticide solution has not yet dried, and even more so not when it is raining.

II. What methods are there for bagging apples?

1. Sterilize and kill pests before bagging

Sterilization and pest control before bagging must be thorough, and care must be taken to protect the leaves. The period from the apple flowering stage to just before bagging is a sensitive time for fruit infection. Ring rot, anthracnose, moldy core, and other diseases easily invade the fruit during this period and remain latent without showing symptoms, so pesticide and fertilizer sprays must be applied regularly.

2. Thin the fruit strictly

When setting the fruit, leave one fruit every 20-25 cm, keep the central fruit and fruit with a long stalk, and thin out poorly developed fruit and fruit with injuries or disease, strictly controlling the number of fruit retained.

3. Supplement calcium before bagging

Because apples after bagging remain for a long time in a dark, humid micro-environment, their ability to absorb calcium is especially poor, so calcium must be sprayed at least 2-3 times before bagging.

4. Bagging techniques must be standardized

Before bagging, the quality of the fruit bags must be well chosen, and operations must strictly follow the bagging technical procedures: the seal must be tight, and the bag must not cling tightly to the young fruit, and so on, so as to avoid a rough interior, fruit russeting, and sunscald.

5. Pay attention to the overall level of the orchard

Wind disasters have a great impact on bagged apples. Fruit growers in mountainous areas are advised to pay attention to two points when bagging: first, low-lying, wind-sheltered orchards should use more paper bags, while windy mountain-ridge orchards should use more film bags; second, on each fruit tree, the windward side and the upper part of the canopy should use more film bags, while the leeward side of the canopy, the lower part of the canopy, and the inner canopy should use more paper bags.