Avocado Production in Asia and the Pacific - United Nations in ...

compost and cattle manure is the well-adopted practice in home gardens, where application
of NPK is not usually carried out.
5.3 Weeding and mulching
As the avocado is a surface feeder, clean weeding is not recommended as any
damage to the root system can accelerate Phytopthora infection. Generally, farmers perform
weed control by slashing and using the weeds for mulching. Chemical control is not in
practice in most avocado orchards. Since weeds contribute to the spread of diseases and
pests, orchards have to be kept relatively weed-free. When weeds are slashed and removed,
they are used as a mulch which helps moisture retention during the dry season. In largescale
cultivation, Peuraria is grown as a green mulch to control weeds. Generally, in home
gardens, mulching is not practised.
5.4 Supplementary irrigation
Like most of the other perennial fruit crops, avocado is grown as a rainfed crop. As a
result of this, avocado undergoes two major water stress periods, during January to April and
July to September, usually causing high flower and fruitlet drop during January to April, and
heavy fruit drop during July to September. Any means of providing supplementary irrigation
to the crop could easily minimize flower and fruit drop during these dry spells. Usually, in
home gardens, growers resort to hand watering during these periods of stress. Most orchards
minimize water loss by using live or dead mulches.
5.5 Control of pest and diseases
So far, there have been no major outbreaks of diseases recorded in Sri Lanka.
Phytophthora root rot, scab and canker are the main diseases that affect avocado. As far as
the post-harvest diseases are concerned, anthracnose and stem-end rot are the most common.
Fruit fly and shot hole borer are the major pests in Sri Lanka. Control of fruit fly can
be achieved by use of pheromone traps immediately after fruit-set. As avocado is mainly a
home-garden crop, and fetches very low prices in the local markets, chemical control
measures are not adopted by the growers.
6. HARVESTING OF FRUITS AND YIELDS
Although maturity indices have been developed to detect the correct stage of
maturity, traders use only the size of the fruit as an index. During the early season, fruits are
often harvested premature and during the harvesting season fruits often become over-mature.
Pre-mature harvesting results in poor quality fruits with very high post-harvest losses.
Similarly, delayed harvesting results in very high post-harvest losses due to incidence of
some diseases that attack the fruit after harvest. Fruits are harvested using a picking-pole
attaching a net bag to prevent falling of fruits during harvesting. It is a common practice
among traders to remove the stalk attached to the fruit before sending fruits to the market.
This operation leads to mechanical damage at the stem end which predisposes the fruit to
pathogenic stem-end rot development. The major cause for post-harvest losses of avocado is
stem-end rot, which increases the price gap between consumer and grower.
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