Pollination management

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Pollination management" – news · newspapers · books · scholar · JSTOR (December 2007) (Learn how and when to remove this template message)

Pollination management is the horticultural practices that accomplish or enhance pollination of a crop, to improve yield or quality, by understanding of the particular crop's pollination needs, and by knowledgeable management of pollenizers, pollinators, and pollination conditions.

While people think first of the

that is essential for production of hybrid seeds and some greenhouse situations, and even pollination machines.

Pollinator decline

With the decline of both wild and domestic pollinator populations, pollination management is becoming an increasingly important part of horticulture. Factors that cause the loss of pollinators include pesticide misuse, unprofitability of beekeeping for honey, rapid transfer of pests and diseases to new areas of the globe, urban/suburban development, changing crop patterns, clearcut logging (particularly when mixed forests are replaced by monoculture pine), clearing of hedgerows and other wild areas, bad diet because of loss of floral biodiversity,^[1] and a loss of nectar corridors for migratory pollinators. With the declining habitat and resources available to sustain bee populations, populations are declining. ^[2]

Importance

The increasing size of fields and orchards (

throughout the growing season to build up their numbers.

Crops that traditionally have had managed pollination include

Some crops, especially when planted in a monoculture situation, require a very high level of pollinators to produce economically viable crops, especially if depending on the more generalized honeybee. 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

alfalfa leafcutter bee

.

In the case of the kiwifruit, its flowers do not even produce nectar, so that honeybees are reluctant to even visit them, unless present in such overwhelming numbers that they do so incidentally. This has led bumblebee pollination companies to begin offering their services for kiwifruit, as they appear to be far more efficient at the job than honeybees, even more efficient than hand pollination.[5]

Number of hives needed per unit area of crop pollination^[6]

Common name	number of hives per acre	number of hives per hectare	number of bee visits per square meter/minute
Alfalfa[7]	1, (3–5)	2.5, (4.9–12)
Almonds	2–3	4.9–7.4
Apples (normal size)	1	2.5
Apples (semi dwarf)	2	4.9
Apples (dwarf)	3	7.4
Apricots	1	2.5
Blueberries	3–4	7.4–9.9	2.5
Borage[8]	0.6–1.0	1.5–2.5
Buckwheat[8]	0.5–1	1.2–2.5
Canola	1	2.5
Canola (hybrid)[8]	2.0–2.5	4.9–6.2
Cantaloupes[9]	2–4, (average 2.4)	4.9–9.9, (average 5.9)
Clovers[8]	1–2	2.5–4.9
Cranberries	3	7.4
Cucumbers[9]	1–2, (average 2.1)	2.5–4.9, (average 5.2)
Ginseng	1	2.5
Muskmelon[10][11]	1–3	2.5–7.4
Nectarines	1	2.5
Peaches	1	2.5
Pears	1	2.5
Plums	1	2.5
Pumpkins	1	2.5
Raspberries[8]	0.7–1.3	1.7–3.2
Squash[10]	1–3	2.5–7.4
Strawberries[8]	1–3.5	2.5–8.6
Sunflower	1	2.5
Trefoil[8]	0.6–1.5	1.5–3.7
Watermelon[9]	1–3, (average 1.3)	2.5–4.9, (average 3.2)
Zucchini	1	2.5

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 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.^[12]

Types of pollinators

Organisms that are currently being used as pollinators in managed pollination are

to pollinate them.

The

Cooperative extension service

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

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, apiculture, zoology (especially entomology), ecology, and botany.

Improving pollination with suboptimal bee densities

Growers’ demand for beehives far exceeds the available supply. The number of managed beehives in the US has steadily declined from close to 6 million after WWII, to less than 2.5 million today. In contrast, the area dedicated to growing bee-pollinated crops has grown over 300% in the same time period. To make matters worse, in the past five years we have seen a decline in winter managed beehives, which has reached an unprecedented rate near 30%. At present, there is an enormous demand for beehive rentals that cannot always be met. There is a clear need across the agricultural industry for a management tool to draw pollinators into cultivations and encourage them to preferentially visit and pollinate the flowering crop. By attracting pollinators like honeybees and increasing their foraging behavior, particularly in the center of large plots, we can increase grower returns and optimize yield from their plantings.^{[citation needed]}

References

Further reading

• Sihag, R.C. 1995.Pollination Biology: Environmental Factors and Pollination. Rajendra Scientific Publishers, Hisar, 195p.
• Sihag, R.C.1995. Pollination Biology: Pollination, Plant Reproduction and Crop Seed Production.Rajendra Scientific Publishers, Hisar, 210p.
• Sihag, R.C.1997. Pollination Biology: Basic and Applied Principles. Rajendra Scientific Publishers, Hisar, 215p.

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