How to Regulate the Production Period in Mango Cultivation
Mango generally flowers around December to January and matures from May to July, which happens to coincide with the peak production season of many other fruits, causing prices to plummet and often leaving growers with nothing to show for their efforts. Conversely, in the off-season, prices rise due to low supply, but this makes consumers pay more, and with growers having no fruit to sell, their income is also extremely limited. Therefore, if horticultural cultivation techniques can be applied to regulate the mango production period, maximizing off-season production and reducing supply during the peak season (June to August), mango prices can become more reasonable and stable, benefiting both producers and consumers. At the same time, proper production period regulation can directly reduce storage costs and provide consumers with fresh, high-quality fruit to enjoy.
1. Advancing the Production Period
Native mango varieties have a habit of flowering off-season, generally blooming on mature branches of older trees, with timing ranging from August to November. Therefore, how to prompt new shoots of the plant to rapidly transition from vegetative growth to reproductive growth is the prerequisite for promoting flower bud differentiation. The methods and steps for advancing the production period are as follows:
1. For native varieties, select trees 15 years or older, preferably those with vigorous growth. Fruit on the tree during that year must be harvested early; when no fruit is hanging on the tree, vegetative growth can be promoted and new shoots and branches can grow rapidly. When harvesting the current year's fruit early in April, compound fertilizer No. 5 should be applied at this time, about 10 to 15 kg per tree, depending on the tree's growth condition.
2. When the new shoots emerge, turn green, and are about to mature, spray the plant with a high-phosphorus-potassium liquid fertilizer, once every 10 days for three consecutive applications, to promote the rapid transition of new shoots to reproductive growth. At this time, pesticides can be mixed in to prevent the new shoots from being damaged by leafhoppers and anthracnose.
3. In June, perform girdling on the trunk of native variety trees, that is, at about 50 cm above the ground on the main trunk, use a saw to make a ring cut forming a circle; the cut must connect all the way around, deep enough to reach the phloem but not damaging the xylem, but do not perform ring barking (complete girdling), as that will make healing difficult, and the tree will quickly weaken afterward and be hard to restore. For the Irwin variety, girdling and ring barking must not be performed; after years of observation, about 30% of trees treated this way will weaken or die as a result.
4. In July, use 39.5% Ethrel growth regulator at 2500 times dilution mixed with high-phosphorus-potassium liquid fertilizer at 100 times dilution, once every 10 days for a total of three sprays, but this must be done at dusk or on cloudy days to prevent the growth regulator from being decomposed by sunlight and affecting its efficacy. If the above treatments are effective, early flowers will open from October to early November, but the rate is not very high, about 20%.
5. After flowering in October, since it is late autumn and the temperature is around 25 to 28 degrees C, which is the peak season for pollinating insect activity, they should be well protected to promote pollination and help normal fruit set. However, late autumn is the dry season in the southern region, so drip irrigation or diverted irrigation should be carried out to promote pollination, help normal fruit set, and also prevent boron deficiency and promote the enlargement of young fruit.
6. When young fruit sets in November, nitrogen fertilizer should be applied as appropriate to promote rapid growth of young fruit. Since it is winter, fruit development is very slow, and fruit thinning should be carried out early, because the thinning period is short and the work is slow and labor-intensive. The best position for retaining fruit is the center of the fruit cluster, and only 1 to 2 fruits can be retained per cluster; otherwise, the fruit will not grow large. The small fruits removed during thinning can be used as “lover's fruit”.
7. During the fruit enlargement period in February, which is the season when the northeast monsoon is strongest, the fruit is very easily infected with black spot disease due to external damage and rain, so prevention should be carried out early, because once infected it cannot be treated and will lose its commercial value.
8. After early production period treatment of Irwin mango, from young fruit to the enlargement period, irregular fruit cracking is easily induced, so soil moisture control should be attended to. At the same time, anthracnose and black spot disease should also be prevented. During the fruit enlargement period, because the temperature is low and sunlight is relatively scarce, the fruit's color cannot develop; at this time, branches should be pruned to maintain good ventilation and sufficient sunlight, and phosphorus-potassium liquid fertilizer should be appropriately applied as foliar fertilizer to promote color development.
2. Delaying the Production Period
Varieties introduced from the United States have the varietal characteristic of producing a second round of flowers after the flower clusters are damaged by cold. When fruit set is normal, this habit of a second flowering is not valued because it is unrelated to yield. However, if the flower clusters produced during the normal flowering period are damaged by cold fronts and prolonged rain, the technique of removing flower clusters can be applied to delay the flowering period, avoid the cold front, and effectively stabilize production, increase yield, and extend the production period. The methods and steps for delaying the production period are:
1. Timing of flower removal: For the Irwin variety, remove flowers at “Beginning of Spring” (February 4); for the Keith and Sensation varieties, flowers should be removed at “Rain Water” (February 19). This can increase the re-flowering rate.
2. After fruit harvest last year, an additional 20% of fertilizer should be applied to supply the nutrients needed for flowering one extra time. At the same time, strong plants should be selected for flower removal treatment, which can increase the re-flowering rate.
3. After flower removal, some branches will grow new shoots and flower clusters together; the new shoots should be removed immediately to prevent nutrient competition. After the regenerated flowers emerge, drip irrigation must be carried out immediately to promote pollination and fruit enlargement.
4. After flower removal, before re-flowering and during the young fruit stage, it is advisable to spray calcium chloride at 500 times dilution mixed with boric acid at 400 times dilution to prevent boron deficiency; after spraying, the pollen germination rate can be increased and the fruit drop rate reduced.
5. When applying the flower removal technique to delay the production period of American varieties, it should be carried out when mango flowering encounters harsh conditions such as cold fronts, prolonged rain, and frost damage; this can increase the fruit set rate. If a warm winter with favorable weather is encountered, flower removal treatment should not be carried out.
6. Native mango varieties do not have the habit of a second flowering, so flower removal treatment must not be carried out on them.
7. If flower removal is carried out for three consecutive years, the plant's growth vigor will noticeably weaken; flower removal should be stopped for one year, nutrition management should be strengthened, and it can be carried out again the following year.
8. Other cultivation and management methods are the same as general extension methods.
Applicable regions: Subtropical