Care and management of Lychee orchards in Nepal
Training and pruning of plants
Usually, training and pruning are not done in lychee due to its evergreen nature. However, some farmers remove the branches or twigs from the soil surface to 45 cm height of the plants while others remove up to 60 to 75 cm height of the plant. These days nurserymen do these operations at the nursery. In some areas like in East and Central Terai districts the central parts of the lychee plants are removed so that side branches are encouraged to develop and central parts are open. Removing the central branches/parts of the plants, which do not receive sunlight and produce very little fruit, is also common even with large trees. These operations are done during December-January both in the Terai and the hills.
Unlike temperate fruit crops, annual pruning practices are not common in lychee orchards. Many farmers believe that removing long twigs along with fruit at harvest is a useful pruning method, but other commercial growers reported that removing fruit clusters, i.e. panicles only, at harvest without removing the twigs or branches and leaves produce more fruit than removing fruit with twigs in the coming season.
Manure and fertilizer
Annual application of the following manure and fertilizers after a year of planting are recommend for young trees before fruiting up to 5-6 years after planting
· FYM or Compost= 30 kg per plant
· DAP= 100 g per plant
· Muriate of Potash= 100 g per plant
· Urea= 100 g per plant
Lychee starts producing fruits from 5-6 years after planting in the Terai and 6-8 years after planting in the hills. The manure and fertilizer recommendations for bearing trees are as follows. These recommendations are followed or even exceeded by commercial lychee growers.
Organic Manure = 50 kg per plant
DAP = 150 g per plant at 6 years of age and increased by 100 g each year up to 15 years and as a constant dose from 15 years onwards.
Urea = 100 g per plant at 6 years of age and increased by 100 g each year up to 15 years and as a constant dose from 15 years onwards.
Muriate of Potash = 100 g per plant per at 6 years of age and increased by 100 g each year up to 15 years and as a constant dose from 15 years onwards.
The manure and fertilizers are applied in the winter months of December and January.
Weeding
Weeds in well developed trees are not a problem. They are a problem in the early stages of plant growth. Farmers keep the young plants and the orchard clean by hand weeding and use mulches of dry grass like rice-straw to keep down the growth of weeds around the young lychee plants and conserve moisture.
Mulching
Mulching of young plants around the root and stem zone by using local materials like dry grass, dry weeds, dry straw etc., immediately after planting is a common practice followed by lychee growers due to the advantages of weed control, soil moisture conservation and addition of organic matter to the soil.
This mulching practice is commonly done from the end of the monsoon to conserve residual soil moisture. In rainfed conditions, farmers reported that mulched plants growth is faster and fruit production better than those of non-mulched plants.
Supplementary irrigation
Lychee is cultivated under non-irrigated/rainfed conditions in both the hills and Terai except in a few isolated cases. However, growers who were able to provide water just before blooming to the fruit maturing stage (mid-February to early-May) reported that fruit quality and production increased significantly. Hence, in recent years the introduction of drip irrigation has become very popular among the resource rich farmers where water is scarce. However, in all cases, regular watering is applied to the seedlings after planting until the plants are well established so that root zones are kept moist.
Diseases
In Nepal, no serious diseases limiting production and productivity of lychee have been observed or recorded.
Pests
Lychee mite (Eriophyes litchi)
Lychee mite is one of the biggest problems in both the Terai and hills. The pest attacks new shoots at the beginning of spring and if the attacks continue, the terminal growth is checked and tree vigour reduced due to reduction in photosynthesis. Fruit produced from affected plants are poor in quality and marketability and yield is also drastically reduced. Use of wettable sulphur at the rate of 2 g per litre of water before bud break is found to be very effective. Spraying two times at 10 days intervals further improved crop vigour and fruit yield.
Lychee bug
This pest attacks the young leaves by sucking the sap from the leaves and tender twigs and branches. In uncontrolled conditions leaves curl, wrinkle and die. In heavy infection new stem twigs also died. In Nepal, this pest is controlled by the application of chloropyriphos + Cypermethion at the rate of 2 ml per litre of water before flowering and two times after the fruits are set.
Fruit worm
The fruit worm is not a serious problem and growers reported that damage caused by this pest is small. However, this pest is also kept under control by above operation.
Fruit cracking
This problem is more serious in Terai orchards and is most common in dry than in relatively moist orchard soils. Cracked fruits are commonly seen in the mid-western Terai districts because the soils of this area are drier than those of central and eastern parts of the country.
Farmers in Sarlahi district reported that thick mulching of lychee plants with local materials while there is a rain in mid-September reduces the cracking.
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