Pollination management
Encyclopedia
Pollination
Pollination is the process by which pollen is transferred in plants, thereby enabling fertilisation and sexual reproduction. Pollen grains transport the male gametes to where the female gamete are contained within the carpel; in gymnosperms the pollen is directly applied to the ovule itself...
of a crop, to improve yield or quality, by understanding of the particular crop's pollination needs, and by knowledgeable management of pollenizer
Pollenizer
A pollenizer or polleniser, sometimes pollinizer or polliniser is a plant that provides pollen.In American English, the words pollenizer and pollinator are often confused: A pollinator is the biotic agent that moves the pollen, such as bees, moths, bats, and birds...
s, pollinator
Pollinator
A pollinator is the biotic agent that moves pollen from the male anthers of a flower to the female stigma of a flower to accomplish fertilization or syngamy of the female gamete in the ovule of the flower by the male gamete from the pollen grain...
s, and pollination conditions.
Pollinator decline
With the decline of both wild and domestic pollinator populations, pollination management is becoming an increasingly important part of horticultureHorticulture
Horticulture is the industry and science of plant cultivation including the process of preparing soil for the planting of seeds, tubers, or cuttings. Horticulturists work and conduct research in the disciplines of plant propagation and cultivation, crop production, plant breeding and genetic...
. Factors that cause the loss of pollinators
Pollinator decline
The term pollinator decline refers to the reduction in abundance of pollinators in many ecosystems worldwide during the end of the twentieth century....
include pesticide misuse
Pesticide misuse
Under United States laws, pesticide misuse is the use of a pesticide in a way that violates laws regulating their use or endangers humans or the environment; many of these regulations are laid out in the Federal Insecticide, Fungicide, and Rodenticide Act...
, unprofitability of beekeeping
Beekeeping
Beekeeping is the maintenance of honey bee colonies, commonly in hives, by humans. A beekeeper keeps bees in order to collect honey and other products of the hive , to pollinate crops, or to produce bees for sale to other beekeepers...
for honey
Honey
Honey is a sweet food made by bees using nectar from flowers. The variety produced by honey bees is the one most commonly referred to and is the type of honey collected by beekeepers and consumed by humans...
, rapid transfer of pests and diseases to new areas of the globe, urban/suburban development, changing crop patterns, clearcut logging
Logging
Logging is the cutting, skidding, on-site processing, and loading of trees or logs onto trucks.In forestry, the term logging is sometimes used in a narrow sense concerning the logistics of moving wood from the stump to somewhere outside the forest, usually a sawmill or a lumber yard...
(particularly when mixed forests are replaced by monoculture
Monoculture
Monoculture is the agricultural practice of producing or growing one single crop over a wide area. It is also known as a way of farming practice of growing large stands of a single species. It is widely used in modern industrial agriculture and its implementation has allowed for large harvests from...
pine), clearing of hedgerows and other wild areas, loss of nectar corridors for migratory pollinators, and human paranoia of stinging insects (killer bee hype).
In 1989, following Hurricane Hugo
Hurricane Hugo
Hurricane Hugo was a classical, destructive and rare Cape Verde-type hurricane which struck the Caribbean islands of Guadeloupe, Montserrat, St. Croix, Puerto Rico and the USA mainland in South Carolina as a Category 4 hurricane during September of the 1989 Atlantic hurricane season...
, massive aerial applications for mosquito
Mosquito
Mosquitoes are members of a family of nematocerid flies: the Culicidae . The word Mosquito is from the Spanish and Portuguese for little fly...
es were done in South Carolina
South Carolina
South Carolina is a state in the Deep South of the United States that borders Georgia to the south, North Carolina to the north, and the Atlantic Ocean to the east. Originally part of the Province of Carolina, the Province of South Carolina was one of the 13 colonies that declared independence...
. The following year, watermelon growers who did not place beehives
Beehive (beekeeping)
A beehive is an enclosed structure in which some honey bee species of the subgenus Apis live and raise their young. Natural beehives are naturally occurring structures occupied by honeybee colonies, while domesticated honeybees live in man-made beehives, often in an apiary. These man-made...
in the fields, observed the fruit begin to develop, then abort, or develop into small deformed fruit. There were entire fields that never yielded a single usable melon. Some growers went out of business; others began to seriously manage pollination. Since beekeepers were also heavily damaged by the mosquito spraying, the supply of bees for pollination was critically short for several years.
Importance of pollination management
The increasing size of fields and orchards (monocultureMonoculture
Monoculture is the agricultural practice of producing or growing one single crop over a wide area. It is also known as a way of farming practice of growing large stands of a single species. It is widely used in modern industrial agriculture and its implementation has allowed for large harvests from...
) increase the importance of pollination management. Monoculture can cause a brief period when pollinators have more food resources than they can use, while other periods of the year can bring starvation or pesticide contamination of food sources. Most pollinator species rely on a steady nectar source
Nectar source
A nectar source is a flowering plant that produces nectar as part of its reproductive strategy. These plants create nectar, which attract pollinating insects and sometimes other animals such as birds....
and pollen source
Pollen source
The term pollen source is often used in the context of beekeeping and refers to flowering plants as a source of pollen for bees or other insects. Bees collect pollen as a protein source to raise their brood. For the plant, the pollinizer, this can be an important mechanism for sexual reproduction,...
throughout the growing season to build up their numbers.
Crops that traditionally have had managed pollination include apple
Apple
The apple is the pomaceous fruit of the apple tree, species Malus domestica in the rose family . It is one of the most widely cultivated tree fruits, and the most widely known of the many members of genus Malus that are used by humans. Apple grow on small, deciduous trees that blossom in the spring...
, almond
Almond
The almond , is a species of tree native to the Middle East and South Asia. Almond is also the name of the edible and widely cultivated seed of this tree...
s, pear
Pear
The pear is any of several tree species of genus Pyrus and also the name of the pomaceous fruit of these trees. Several species of pear are valued by humans for their edible fruit, but the fruit of other species is small, hard, and astringent....
s, some plum
Plum
A plum or gage is a stone fruit tree in the genus Prunus, subgenus Prunus. The subgenus is distinguished from other subgenera in the shoots having a terminal bud and solitary side buds , the flowers in groups of one to five together on short stems, and the fruit having a groove running down one...
and cherry
Cherry
The cherry is the fruit of many plants of the genus Prunus, and is a fleshy stone fruit. The cherry fruits of commerce are usually obtained from a limited number of species, including especially cultivars of the wild cherry, Prunus avium....
varieties, blueberries, cranberries
Cranberry
Cranberries are a group of evergreen dwarf shrubs or trailing vines in the subgenus Oxycoccus of the genus Vaccinium. In some methods of classification, Oxycoccus is regarded as a genus in its own right...
, cucumber
Cucumber
The cucumber is a widely cultivated plant in the gourd family Cucurbitaceae, which includes squash, and in the same genus as the muskmelon. The plant is a creeping vine which bears cylindrical edible fruit when ripe. There are three main varieties of cucumber: "slicing", "pickling", and...
s, cantaloupe
Cantaloupe
"Rockmelon" redirects here, for the band see Rockmelons. See also Cantaloupe .Cantaloupe refers to a variety of Cucumis melo, a species in the family Cucurbitaceae which includes nearly all melons and squashes. Cantaloupes range in size from...
, watermelon
Watermelon
Watermelon is a vine-like flowering plant originally from southern Africa. Its fruit, which is also called watermelon, is a special kind referred to by botanists as a pepo, a berry which has a thick rind and fleshy center...
, alfalfa
Alfalfa
Alfalfa is a flowering plant in the pea family Fabaceae cultivated as an important forage crop in the US, Canada, Argentina, France, Australia, the Middle East, South Africa, and many other countries. It is known as lucerne in the UK, France, Australia, South Africa and New Zealand, and known as...
seeds, onion
Onion
The onion , also known as the bulb onion, common onion and garden onion, is the most widely cultivated species of the genus Allium. The genus Allium also contains a number of other species variously referred to as onions and cultivated for food, such as the Japanese bunching onion The onion...
seeds, and many others. Some crops that have traditionally depended entirely on chance pollination by wild pollinators need pollination management nowadays to make a profitable crop.
Some crops, especially when planted in a monoculture situation, require a very high level of pollinators to produce economically viable crops. This may be because of lack of attractiveness of the blossoms, or from trying to pollinate with an alternative when the native pollinator is extinct or rare. These include crops such as alfalfa, cranberries, and kiwifruit
Kiwifruit
The kiwifruit, often shortened to kiwi in many parts of the world, is the edible berry of a cultivar group of the woody vine Actinidia deliciosa and hybrids between this and other species in the genus Actinidia....
. This technique is known as saturation pollination
Saturation pollination
Saturation pollination is a pollination technique for agricultural crops in areas dominated by non-crop plant species that are preferred by pollinators. The technique involves keeping a larger number of bee colonies than normally maintained for honey production so as to exhaust the preferred plants...
. In many such cases, various native bees are vastly more efficient at pollination (e.g., with blueberries), but the inefficiency of the honey bees is compensated for by using large numbers of hives, the total number of foragers thereby far exceeding the local abundance of native pollinators. In a very few cases, it has been possible to develop commercially viable pollination techniques that use the more efficient pollinators, rather than continued reliance on honey bees, as in the management of the alfalfa leafcutter bee
Alfalfa leafcutter bee
Megachile rotundata, the alfalfa leafcutter bee or lucerne leafcutter bee is a European bee that has been introduced to other regions...
.
| Common name | number of hives per acre |
number of hives per hectare |
number of bee visits per square meter/minute |
|---|---|---|---|
| Alfalfa | 1, (3–5) | 2.5, (4.9–12) | |
| Almonds | 2 /acre | ||
| Apples (normal size) | 1 /acre | ||
| Apples (semi dwarf) | 2 /acre | ||
| Apples (dwarf) | 3 /acre | ||
| Apricots | 1 /acre | ||
| Blueberries | 3 /acre | 2.5 | |
| Borage | 0.6 /acre | ||
| Buckwheat | 0.5 /acre | ||
| Canola | 1 /acre | ||
| Canola (hybrid) | 2 /acre | ||
| Cantaloupes | 2–4, (average 2.4) | 4.9–9.9, (average 5.9) | |
| Clovers | 1 /acre | ||
| Cranberries | 3 /acre | ||
| Cucumbers | 1–2, (average 2.1) | 2.5–4.9, (average 5.2) | |
| Ginseng | 1 /acre | ||
| Muskmelon | 1 /acre | ||
| Nectarines | 1 /acre | ||
| Peaches | 1 /acre | ||
| Pears | 1 /acre | ||
| Plums | 1 /acre | ||
| Pumpkins | 1 /acre | ||
| Raspberries | 0.7 /acre | ||
| Squash | 1 /acre | ||
| Strawberries | 1 /acre | ||
| Sunflower | 1 /acre | ||
| Trefoil | 0.6 /acre | ||
| Watermelon | 1–3, (average 1.3) | 2.5–4.9, (average 3.2) | |
| Zucchini | 1 /acre |
It is estimated that about one hive per acre will sufficiently pollinate watermelons. In the 1950s when the woods were full of wild bee trees, and beehives were normally kept on most South Carolina
South Carolina
South Carolina is a state in the Deep South of the United States that borders Georgia to the south, North Carolina to the north, and the Atlantic Ocean to the east. Originally part of the Province of Carolina, the Province of South Carolina was one of the 13 colonies that declared independence...
farms, a farmer who grew ten acres (4 ha) of watermelons would be a large grower and probably had all the pollination needed. But today's grower may grow 200 acres (80 ha), and, if lucky, there might be one bee tree left within range. The only option in the current economy is to bring beehives to the field during blossom time.
See also: List of crop plants pollinated by bees
Types of pollinators
Organisms that are currently being used as pollinators in managed pollination are honey beeHoney bee
Honey bees are a subset of bees in the genus Apis, primarily distinguished by the production and storage of honey and the construction of perennial, colonial nests out of wax. Honey bees are the only extant members of the tribe Apini, all in the genus Apis...
s, bumblebee
Bumblebee
A bumble bee is any member of the bee genus Bombus, in the family Apidae. There are over 250 known species, existing primarily in the Northern Hemisphere although they are common in New Zealand and in the Australian state of Tasmania.Bumble bees are social insects that are characterised by black...
s, alfalfa leafcutter bee
Alfalfa leafcutter bee
Megachile rotundata, the alfalfa leafcutter bee or lucerne leafcutter bee is a European bee that has been introduced to other regions...
s, and orchard mason bee
Orchard mason bee
Osmia lignaria, commonly known as the orchard mason bee or blue orchard bee, is a megachilid bee that makes nests in reeds and natural holes, creating individual cells for their brood that are separated by mud dividers. Unlike carpenter bees, they cannot drill holes in wood. O...
s. Other species are expected to be added to this list as this field develops. Humans also can be pollinators, as the gardener who hand pollinates
Hand pollination
Hand pollination is a technique used when natural, or open pollination is insufficient or undesirable. The most common techniques are for crops such as cucurbits, which may exhibit poor pollination by fruit abortion, fruit deformity or poor maturation...
her squash blossoms, or the Middle East
Middle East
The Middle East is a region that encompasses Western Asia and Northern Africa. It is often used as a synonym for Near East, in opposition to Far East...
ern farmer, who climbs his date palm
Date Palm
The date palm is a palm in the genus Phoenix, cultivated for its edible sweet fruit. Although its place of origin is unknown because of long cultivation, it probably originated from lands around the Persian Gulf. It is a medium-sized plant, 15–25 m tall, growing singly or forming a clump with...
s to pollinate them.
The Cooperative extension service
Cooperative extension service
The Cooperative Extension Service, also known as the Extension Service of the USDA, is a non-formal educational program implemented in the United States designed to help people use research-based knowledge to improve their lives. The service is provided by the state's designated land-grant...
recommends one honey bee hive per acre (2.5 hives per hectare) for standard watermelon varieties to meet this crop's pollination needs. In the past, when fields were small, pollination was accomplished by a mix of bees kept on farms, bumblebees, carpenter bees, feral honey bees in hollow trees and other insects. Today, with melons planted in large tracts, the grower may no longer have hives on the farm; he may have poisoned many of the pollinators by spraying blooming cotton; he may have logged off the woods, removing hollow trees that provided homes for bees, and pushed out the hedgerows that were home for solitary native bees and other pollinating insects.
Planning for improved pollination
Before pollination needs were understood, orchardists often planted entire blocks of apples of a single variety. Because apples are self sterile, and different members of a single variety are genetic cloneCloning
Cloning in biology is the process of producing similar populations of genetically identical individuals that occurs in nature when organisms such as bacteria, insects or plants reproduce asexually. Cloning in biotechnology refers to processes used to create copies of DNA fragments , cells , or...
s (equivalent to a single plant), this is not a good idea. Growers now supply pollenizers, by planting crab apples interspersed in the rows, or by grafting crab apple limbs on some trees. Pollenizers can also be supplied by putting drum bouquets of crab apples or a compatible apple variety in the orchard blocks.
The field of pollination management cannot be placed wholly within any other field, because it bridges several fields. It draws from horticulture
Horticulture
Horticulture is the industry and science of plant cultivation including the process of preparing soil for the planting of seeds, tubers, or cuttings. Horticulturists work and conduct research in the disciplines of plant propagation and cultivation, crop production, plant breeding and genetic...
, apiculture
Beekeeping
Beekeeping is the maintenance of honey bee colonies, commonly in hives, by humans. A beekeeper keeps bees in order to collect honey and other products of the hive , to pollinate crops, or to produce bees for sale to other beekeepers...
, zoology
Zoology
Zoology |zoölogy]]), is the branch of biology that relates to the animal kingdom, including the structure, embryology, evolution, classification, habits, and distribution of all animals, both living and extinct...
(especially entomology
Entomology
Entomology is the scientific study of insects, a branch of arthropodology...
), ecology
Ecology
Ecology is the scientific study of the relations that living organisms have with respect to each other and their natural environment. Variables of interest to ecologists include the composition, distribution, amount , number, and changing states of organisms within and among ecosystems...
, and botany
Botany
Botany, plant science, or plant biology is a branch of biology that involves the scientific study of plant life. Traditionally, botany also included the study of fungi, algae and viruses...
.
External links
- Insect Pollination Of Cultivated Crop Plants S.E. McGregor, USDA, 1976
- Raising awareness among Canadians about plant pollinators and the importance of monitoring and conserving them J. A. Dyer, Seeds of Diversity Canada, Feb. 2006
- Canadian Pollination Initiative 2009