Almonds, Prunus amygdalus, are mainly planted in the Western Cape, but new
cultivars are planted in other areas of the country. Currently there are more
than 550 hectares plated in South Africa.
The individual trees flower for about 21 days. Most cultivars
are self-incompatible and a compatible polinizer cultivar is planted within the
main production cultivar orchard. The flowers are most receptive for pollination
on the second open day. Honeybees play an essential role in the
cross-pollination of cultivars for a better quality crop. Research Results
A study on almond pollination was conducted during August and
September 1989 near Loskopdam in Mpumalanga. The high density 3 ha. almond
orchard established in 1985, consisted of the cultivars 'Ne Plus Ultra' and
'Pearless' in the ratio 2:1. The test orchard was adjoin by a further 4 ha. of
almonds and 30 ha. of peaches. The rest of the farm was used for cattle and
pasture and uncultivated fields were within the forage rage of the test
colonies. The two most promising competitive wild plants were Aloe grayhedii
var. davyana, and Aloe marlothii.
Honeybee activity remained constant during the day with an
average of 6 bees per tree. Activity however decreased from an average 8 bees
per tree at 50-60% bloom, to 5 bees per tree at full bloom.
The final fruit set was determined 40 days after flowering and
the following results were obtained:
Flowers where pollen was not available from the pollinizer had an average
fruit set of 1%.
Flowers where pollen was available from pollinizer had an average fruit set
Insignificant differences were found in fruit set on the eight wind
directions indicating good pollen movement by the pollinators.
A pollen trap was fitted to one hive. Pollen trapped with this
method was identified with the aid of a light microscope to determine the major
foraging plants in the study area. The results are given in a table:
The results show that although alternative nectar and pollen
sources can attract foragers away from almonds, successful cross-pollination can
In another test, a bee attractant was applied and an increase
of 50% in fruit set was achieved.
It is recommended that 5 -8 hives per ha is placed in or near
the orchard when both target and polliniser cultivar are at 50% flower.
Competitive plants should be removed.
The apple, Malus domestica, is mainly planted in the Western Cape, but new
cultivars are becoming increasingly popular in other areas of the country. In
South Africa more than 22 500 ha are already under cultivation.
The individual trees flower for 10 to 25 days. Most cultivars
are self-incompatible and a compatible polliniser cultivar is planted within the
main production cultivar orchard. Honeybees play an essential role in the
cross-pollination of cultivars for a better quality crop.
The plant produces a nutritious pollen and fair quantity of
nectar but colonies strength usually decline because of pollination
Returning foragers collected at the hive entrances from
colonies placed in an apple orchard showed that within three days of being
placed in the orchard some foragers collected less than 5% apple pollen. It is
therefore imperative that the beekeeper introduces his pollinating bees only at
optimal blossom time, and to eliminate all alternative forage plants.
For good pollination 2-5 hives/ha is recommended. Good tree
coverage by bees is achieved if 3 or more bees per tree at any time of the day
Pollination and fertilization of avocado, Persea americana, are prerequisites
for fruit set and fruit development receptively. In South Africa avocados are
planted on more than 14 800 ha, with a projected growth of 5% annually. A total
of 81 000 tones of fruits were marketed in 2001 with 55% of the crop been
In different surveys it was found that the number and diversity
of insects that visit avocado flowers varies from one orchard to another, and
from one season to another.
Competitive bee-plants can lure bees away. Examples of these
include blackjacks, late flowering saligna gums in some years, or early
Honeybee foraging activity was investigated in a 50 ha orchard
(cv. Hass and Ryan) at Politsi near Tzaneen in the Northern Province. Foragers
returning to the hive were examined for nectar-, water-, pollen- and propolis
loads. No single foraging activity dominated during any time of day or during
the flowering period, indicating that neither pollen nor large volumes of nectar
were available in large quantities. Returning foragers sampled at the hive
entrance throughout the day that carried avocado pollen did not collect mixed
pollen (of other plants) and were therefore specific in their preference.
Avocado flowers proved much more attractive to honeybees than mango and litchi.
To test the value of insect pollination, all insects were
excluded by enclosing inflorescence (flower panicles) with fine mesh bags.
Whereas 400 bagged inflorescence yielded only two fruits, an equal number of
marked but open inflorescence yielded 33 fruits, proving the importance of
Botanical, entomological and horticultural aspects were
combined to study the influence of the pollen donor 'Ettinger' and bees on
'Hass' yields and fruit size. The experiment was carried out in a four-year-old
'Hass' orchard bordered by a row of 'Ettinger'. To study the role of pollinators
cages that excluded all insects were erected over groups of trees consisting of
the pollinizer and crop cultivar. In one group honeybee colonies were placed
inside the cages to determine the value of honeybees as pollinators. Fruit set
in caged trees with bees was significantly higher than in those without bees.
'Hass' flowers pollinated with 'Ettinger' pollen produced larger and heavier
fruit. Honeybees did not only increase the crop but due to cross-pollination
better quality fruits were produced.
To determine the distribution of honeybees in a commercial
avocado orchard in which every tenth row was a pollinator cultivar, a new method
was applied using fluorescent powder to mark outgoing foragers. During the
evening, a portable UV light was used to scan inflorescences for deposited
powder. The number of visited inflorescences declined with increasing distance
from the hives, up to 300 m along rows of trees. The survey across the rows of
avocado trees and casuarina windbreaks yielded significantly fewer visited
inflorescences, the furthest being only 200 meters from the hives. This shows
that to optimise pollination, colonies should not be more than 150m apart.
The number of colonies required for effective pollination
varies from 2 to 4 per hectare. To establish whether there are enough bees
present to give adequate pollination, the number of bees foraging on the flowers
should be counted between 10 AM and 12 noon on a fine day. This should be
repeated between 2 PM and 4 PM. The timing is important because it is at these
times that the flowers produce nectar and pollen optimally. Five bees per squire
meter of flowering canopy tree area, or five bees per twenty inflorescence
indicate that an adequate number of foragers are present in the
Canola, Brassica napus var. oleifera, is a member of the cabbage family. It
is mainly planted in the south-western Cape for its oil and, on small scale, for
seed production in the Free State and northern Cape.
The crop flowers for 5-7 weeks. The flowers are self-compatible, but the
quality and quantity of seeds are greatly increased by honeybee pollination.
The crude protein content of canola pollen is high, stimulating rapid brood
production and swarm build-up that often leads to swarming. In the south-wetern
Cape when the old queen departs Capensis laying workers may take over resulting
in considerable colony losses. Less or weakened colonies also means honey crop
It is recommended that 2-6 hives/ha is used. Honey must be extracted as soon
as possible because conola honey crystallizes quickly in the comb.
Pollination services rendered by beekeepers create direct jobs for thousands
of people, but the secondary role it plays as job creator in farming, packing,
manufacturing, marketing etc. touch the lives of hundreds of thousands of people
in South Africa.
Pollination services rendered by beekeepers create direct jobs
for thousands of people, but the secondary role it plays as job creator in
farming, packing, manufacturing, marketing etc. touch the lives of hundreds of
thousands of people in South Africa.
Estimated value of honeybees in commercial crop pollination in South
Honeybee added value
2 358 106
1 391 154
1 133 477
1 517 289+
7 707 020+
Although each crop to be pollinated has different pollination requirements
there are general rules and standards for pollination units that should be
Litchi, Litchi chinensis, is mainly planted in the subtropical regions of the
country. It is estimated that there are more than 1000 ha planted. The trees
bear three flower types on the same tree: male, female and bisexual, the ratio
varying with cultivar and season. The honeybee is the most important pollinator.
A tree flowers for up to 21 days.
Honeybee foraging activity was investigated in a 10 ha orchard (cv.
Bengal) at Politsi near Tzaneen in the Northern Province. Foragers returning to
the hive was examined for nectar-, water-, pollen- and propolis loads. Nectar
foraging dominated throughout the day, and only small quantities of pollen were
collected by the foragers.
The flowers panicles (inflorescence) of some trees were bagged in fine mesh
bags to exclude insect pollinators. It was found that 95% of bagged panicles did
not set any fruit. Less than one fruit per bagged panicle matured. In contrast,
92% of open (mainly honeybee) pollinated inflorescence bore fruit, with a mean
of 9 fruits (range 0-44) per panicle, indicating the importance of insect
It is recommended that 2-4 hives/ha are placed inside the orchard. Colony
strength increases which can cause the colonies to become more defensive.
Therefore, the colonies should not be placed where farm personnel often pass.
The mango, Mangifera indica, originates from India. The fibreless mango
cultivars 'Haden', 'Alphonse', 'Paheri', 'Mulgoba', and 'Totafari Gren' were
introduced in South Africa between 1920 and 1930. More extensive plantings took
place after 1960 with the introduction of 'Kent', 'Keitt', 'Tommy Atkins' and
'Zill'. Mangos are ranked as the fifth most important subtropical crop in South
Africa, after citrus, banana, avocado and pineapple. The total area under
production is more than 8000 hectares. The largest growing areas are Hoedspruit,
Malelane, Letsitele Valley, Deerpark, Lower Letaba, Trichardsdal, Ofcolaco,
Hazyveiw, Levubu, Louis Trichardt, and Mooketsi.
The 1995/'96 crop was approximately 45 000 tons of which 13% were exported,
26% locally marketed, 44% sold for achar processing, and 9% sold for juice
processing. The value was estimated at R77 500 000.
The crop flowers for approximately 28 days. Pollen grain development in both
male and female flowers is affected by climatic conditions. Cold spells during
pollen development result in low pollen viability and hamper successful pollen
tube growth after pollination. Flowers usually open in the early morning, but
temperatures above 20 °C are required for anther dehiscence and pollen shed.
High humidity affects this process negatively. Certain cultivars have far less
pollen than others do. The stigmas remain receptive for at least 6 hours,
although if not pollinated, receptivity can last up to 3 days. Both male and
female flowers can produce nectar.
Returning foragers were examined for nectar, water, pollen and propolis loads
in a 14 ha. orchard (planted with cultivars Kent and Keitt) in the Letsitele
Valley in the Northern Province. Mango flowers secreted little nectar. However,
bees collected nectar from extra-floral nectar-glands situated at the bases of
the panicles throughout the day. This ensured that foragers returned to the
target crop throughout the flowering period. Small amounts of pollen were
available for the bees to collect from the single viable stamen of each flower.
Foragers visited the flowers throughout the flowering period despite some
competitive nectar and pollen sources in the vicinity, indicating forager
specificity. Foragers made contact with both anthers and stigmas in search for
forage and thus effectively pollinated the flowers.
In testing the influence of insects (but especially honeybees) as
pollinators, 400 bagged inflorescence yielded no fruit while 400 open marked
inflorescence produced 6 fruit. Natural fruit-drop was high and this explained
the low number of fruits that matured.
Pollination recommendation is 3-15 hives/ha. Colony strength decline during
the pollination period and therefore strong and healthy pollination units are
required. Competitive plants should be eliminated.
Pollination for seed production of onions, Allium cepa, is practiced mainly
in the Northern and Western Cape provinces. Pollination occurs when pollen is
transferred from the dehiscing anthers of one floret to a receptive stigma of
another floret. Effective transfer of pollen between florets on an umbel or
between plants must transpire through the action of an outside agent because
self-pollination is almost impossible. In hybrid seed production, a pollinizer
cultivar is planted amongst male-sterile plants, and insect pollination is
The crop flowers between 25 and 30 days. The flowers have nectar and pollen,
but attractiveness is generally low, which can be aggravated by lack of
plentiful soil moisture, fertilization with phosphorus and nitrogen, potassium
in nectar, and beeplant competitors.
It is recommended that 5-12 hives are used per hectare. To ascertain whether
there are enough bees in the field for adequate pollination, bee cover of 100
bees per 30m male fertile plant row, and 40 bees per 30m male sterile (female)
row is satisfactory.
The banded bee pirate, Palarus latifrons, is a predatory wasp that
may cause problems in sandy soil areas. Bees prefer not to collect
nectar from flowers where the potassium content in the nectar is higher than
The plum, Prunus domestica, is mainly planted in the Western Cape. It is
estimated that 4 600 ha are in production in the country. Honeybees are
important pollinators because new cultivars are mostly self-incompatible and
therefore require compatible pollinisers. Individual trees flower between 8-14
days. The stigma of a flower is receptive for 1-2 days before the anthers of
that flower dehisce. The flowers secrete nectar with a low sugar concentration.
The amount of nectar secreted varies between cultivars.
In the Western Cape the pollen loads of returning foragers from the plum
cultivar 'Songold' was collected and the ratio of plum pollen to other plants
determined. Plum pollen was not collected in large quantities, indicating that
it was not very attractive to the bees. Large numbers of commercial colonies are
therefore needed to supply enough bees for satisfactory pollination of this
crop. Flower bearing branches were covered in a fine mesh bag to excluded
insects from pollinating the flowers. The covered branches yielded very view
fruit, indicating the importance of honeybees as pollinators.
It is recommended that 2-6 hives/ ha be used to supply good tree coverage by
bees. Pesticide spraying may cause honeybee mortality and should be avoided by
either closing the hives or moving the colonies out of the orchard during
Colonies used for pollination must be queen-right, have at least 8 brood
frames cocered with bees and 4 brood frames with brood of different stages. For
most crops colonies can be moved into the orchard or field when flowering is at
approximately 10% (i.e. 10% of all flowers have already opened). Colonies should
be placed in groups, preferably forming a circle to limit drifting. One site
should be no more than 400m from the next. If this can't be done, they should be
placed along the edge of the orchard or field. When the colonies are placed in a
line it is best to stagger them as much as possible and turn every second
The colonies must be protected against ants. If there are competitive
bee-plants in or near the orchard, increase the number of colonies, or if
possible remove the plants.
Supplying fresh water is essential throughout the year, because in winter
there may be a shortage of natural water and in summer the colonies are hot and
need more water to maintain the required humidity and temperature for brood