MY EXPERIENCE IN DURIAN CULTIVATION
SCIENTIFIC NAME: Durio zibethinus
FAMILY: Bombacaceae
INTRODUCTION
Durian is one of the most palatable tropical fruits. It is very popular among local people and many foreigners are fond of it as well. The high domestic market demand puts durian into a high-income crop. The discouraging incidence that faces the durian consumers is the inferior fruit quality. Causes of inferior fruit quality are improper cultural practices and immature fruit harvesting. Whatever the cause, the incidence leads to market deterioration and the growers are urged to produce only quality fruits.
The Orchard Physical Component
My orchard is in Saoung village, Klung district, Chantaburi province. The topography is gentle slope with well-drained sandy loam. Levelling of all the 250 rais of land was undertaken to avoid any water-logged spots.
Varieties
There are two leading varieties planted: Chanee and Kradum-thong. The age of the plants ranges from 10-20 years old. Kradum-thong, an early variety, was planted for early marketing, which fetches a high price.
Spacing
Planting distance is 10 x 10 meters which seems to be too close, especially for Kradum-thong variety. The spacing of 14 x 14 meters is advised for the new planters.
Orchard care
1. Soil fertilizer application: The first application is done right after harvesting to restore the tree vigor. Fertilizer grade of 16-20-0 at the rate of 5-6 kg per tree is applied.
The second soil fertilizer application is done when the first leaf flush becomes mature. Potassium sulfate at the rate of 2.5 kg per tree is employed in order to induce flower bud initiation. The third application is done when the fruit is about betel nut size by applying fertilizer grade of 12-12-17-2 at the rate of 3 kg per tree. This application is to ensure good fruit set.
2. Foliar fertilizer application: In case the general vigor of the tree did not recover by soil fertilizer application, foliar application with urea is necessary.
3. Disease control: The most serious durian disease is stem rot caused by Phytophthora palmivora. Diseases of minor importance are fruit anthracnose, flower wilt, leaf spot and leaf fungal disease. The varieties susceptible to Phytophthora palmivora are Kradum-thong, Monthong and Kob. The peak infestation of the disease is at the end of the rainy season. To control stem rot disease, the following steps should be taken:
(a) The orchard must be kept clean from weeds.
(b) Corky bark should be removed from the trunk up to one meter high above ground level.
(c) Apply Ridomil at the rate of 300 grams per tree (mix with water) to the bark-removed area and to the soil around the canopy.
(d) Stem borer, vector of the disease, should be kept under control. The anthracnose which infests leaf and fruit at the end of rainy season can be controlled by Benlate spray at early disease symptom. Cupravit is sprayed to control flower wilt. Leaf spot disease common to the new flushing leaves can be controlled by Difolatan.
4. Insect Control: The main insect pests are red mites, red spider, scale insect and fruit borer. The outbreak of red mite is in August to September. Guzathion A in Parathion solution is recommended as an effective control measure. A mixture of Sevin and White oil is effective in controlling scale insect.
5. Pruning: Pruning should be done after fruit harvesting and repeated after the first fertilizer application. All the pest-infested branches and twigs should be removed. The point of cutting should be as close as possible to the main wood and the wound be applied with Cupravit. It is believed that proper pruning encourages good fruiting.
Fruit Thinning
Kradum-thong is a heavy fruit-bearing variety. therefore fruit thinning is a common practice in this variety. It is suggested that healthy 15-20-year-old tree could bear as much as 150 fruits per tree. In heavy flowering year, flower thinning is also advised. The following criteria are used for flower thinning:
1. Tree conditions: healthy or not healthy.
2. The branch position: horizontal branches can carry more fruits than vertical ones.
3. On smaller branches, fruits should be retained at the near end rather than at the far end.
4. On bigger branches, fruits should be retained at the far end. Flower thinning must be done carefully. Specific characteristic of each of the varieties must be taken into consideration.
Flowers of certain varieties fall easily by a gentle touch, and that thinning should be done at two different stages namely, flowering stage and fruiting stage, to minimize loss.
Weed Control
Weed control must be undertaken regularly. Removal of weeds at the end of the rainy season will facilitate soil moisture evaporation and thus conditions imitating drought can be commenced earlier.
DATE: September 1985
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