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Medhat Nasr <[log in to unmask]>
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Tue, 13 Apr 1999 10:02:54 EDT
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      REPORT ON CROPS AND HONEY BEE POLLINATION SYMPOSIUM
             HELD IN GUELPH, ONTARIO, March 25, 1999
   Shannon Corrigan1, Janet Tam1, Medhat Nasr1, Doug McRory2

1. Ontario Beekeepers' Association, c/o Dept. Environmental Biology,
    University of Guelph, Guelph, Ontario, N1G 2W1.
2. Crop Technology, OMAFRA, 1 W. Stone Road, Guelph, Ontario, N1G
    4Y2.

A successful symposium was held in Guelph on Thursday, March 25,
1999. This symposium was sponsored by Ontario Honey Bee Pollination
Association, Ontario Research Enhancement Program (OREP), and Can-
Adapt Small Projects Intiative. This symposium was part of a project
to bring together both growers and beekeepers for promotion and
marketing of honey bees for pollination. The symposium addressed various
subjects dealing with crops and honey bee pollination. Summary of
presentations is followed:

Basics of Crop Pollination - Dr. Robbin Thorp,
Professor, University of California, Davis, California, USA

Both wild plants and crops are highly dependent on pollinators. Plants which
self-fertilize do not usually require a pollinator, but many plants must out
cross, which does require a pollinator to transfer pollen from another flower
or plant. To maximize pollination and crop yield, plant pollination requirements
must be known. Some plants need to be pollinated by another cultivar
altogether. One complication found with this is that crops are usually planted
in rows consisting of a single cultivar, and honey bees are more
likely to forage along rows rather than across rows or cultivars.

Honey bees can be either pollen foragers or nectar foragers. The pollen
foragers are most efficient for pollination. To enhance pollination, pollen can
be placed on inserts at hive entrances for bees to be dusted with as they leave
the hives. Pollen can also be spread by hand, ground rig, or helicopter. These
methods are costly and time-consuming, and not as effective as predicted.
The best method to increase the efficacy of pollination is to design orchards in
such a way that pollination is maximized. Beekeepers need to educate growers
about the benefits of pollination and the beekeepers, themselves, must learn
about crop requirements.

Economics of Crop Pollination - Doug McRory,
Provincial Apiarist, OMAFRA, Guelph, Ontario

There are several costs involved in providing pollination services. Beekeepers
have to manage their honey bees more intensively to prepare them for
pollination. It is important to have strong bee colonies with good laying queens
and sufficient feed honey and pollen stores. Equipment to move bees, such as
forklifts, booms, trucks, and pallets, are extra investments which require
maintenance. If over 200 colonies are to be moved in a short period of time,
mechanical devices are needed to assist with the physical labour. For
pollinating, honey bee colonies must have 5-6 frames of brood and be
given sufficient room so they will not swarm while pollinating in the
field. This requires additional management input. Colonies placed in
fields for pollinating summer crops cannot be counted on to produce any
honey. Therefore, it is necessary to charge enough to offset the loss in honey
production.

There is room for more colonies to be used for pollination. There are
about 29,000 acres of apples in Ontario that should be using at least 40,000
colonies of honey bees in the spring. Only 10,000- 12,000 colonies are moved
each spring. In the summer 5 000 bee colonies are moved to pollinate other
summer crops. In total, there are 82,000 honey bee colonies in Ontario. The
honey bee industry is a resource that is not being utilized efficiently by
growers. Beekeepers need to market their pollination services more
aggressively. If beekeepers have more orders than they can handle, there are
many more beekeepers with good bees available from other parts of the
province.

On the other hand, crop growers need to be educated about requirements of
their crops for pollination. They should know about pollinizer distribution,
irrigation, cultivars' compatibility, and honey bees to insure efficient pollination.
Recent research showed that the cost/benefit analysis of pollination is
tremendous. Use of honeybees brings in profits of $41 to $192 for every $1
spent on pollination of apple and blueberry, respectively. The estimated value
of insect pollination to Ontario agriculture is over $100 million annually. Our
new challange is everyone who wants bees should be able to obtain them
when they need them to increase production of quality crops in Ontario.
Beekeepers and growers have to work together to meet this challenge.

Apple Pollination with Emphasis on High Density Orchards and Pollen
Movement - Dr. Peter Kevan (Professor) / Dr. Brian Husband (Professor) /
Svenja Belaoussoff (Ph.D. Candidate), University of Guelph, Guelph, Ontario

High density apple orchards are now common throughout southern Ontario,
yet their pollination requirements are poorly, if at all, understood.
Most of the existing literature and recommendations pertain to standard apple
orchards. High density plantings result in rows of dwarf trees that resemble
hedge-rows. Pollinating honey bees tend to follow the rows, thus
often working only a single variety, and only occasionally crossing between
rows to cross-pollinate when adjacent rows are of different varieties. Placing
less than the recommended number of honey bee colonies in an orchard will
result in inadequate pollination. This is a problem for many growers in Ontario.

To better understand pollen dispersal, paternity analyses of seeds were
performed in a recent research project at the University of Guelph. For each
apple variety, the protein gene profile was determined by electrophoresis.
Seeds from each variety were  analyzed to find out which variety(s) was the
pollen donor. Self-fertilization was very low. Most blossoms were pollinated
by more than one variety. In conclusion, it was determined that the
combination and arrangement of varieties in an orchard is important since they
have an effect on the percent of blossoms pollinated. Optimal arrangement of
varieties can help to maximize crop yield.

Colony Preparation for Crop Pollination in Ontario - Roger Congdon,
Commercial Beekeeper, Ontario

To better ensure overwintering survival, mite treatments and feed should be
applied to honey bee colonies in the fall. The hives should be placed in yards
that are easily accessible for moving colonies out after the winter. In the
spring, Terramycin should be applied and colony strength assessed. Only
healthy and properly proportioned (age ratio) hives should be used for
pollination. When placing hives in growers' yards, they should be set
in areas protected from the wind, and on dry ground. These sites should also
be easily accessible to avoid damage for both the grower and beekeeper during
moving. Colony placement should be timed so that the hives are delivered after
spraying, but before the king bloom. It is important that beekeepers and
growers communicate and understand each other's concerns and problems.
Adjacent growers should try to synchronize their activities and work together
so that one grower does not spray while the others still have honey bees in
their fields which could be affected. Another important factor to be aware of
is that different crops and crop varieties are not pollinated equally, so this
can affect the number of hives required.

Management of Honey Bee Colonies for Effective Crop Pollination -
Dr. Robbin Thorp, Professor, University of California, Davis, California, USA

Communication between beekeepers and growers is essential for effective
crop pollination. It is recommended that beekeepers and growers discuss and
agree upon the following issues before the pollination season begins:
     - movement of colonies in and out
     - spraying of harmful insecticides (advance warning must be given to
beekeeper so that hives can be removed)
     - definition of colony strength (number of frames of bees, brood
area)
     - distribution pattern in the orchard
     - beekeeper inspection of colonies
     - adequate supply of water
     - rental fee (how much? when due?)

For growers to maximize pollination:
     - use strong hives
     - use the recommended number of hives per acre for that specific
crop
     - put colonies inside orchard or field in clusters
     - move colonies in at first flower
     - disc cover crop (ie. remove flowering weeds between crop rows) to
reduce competition with certain crops to be pollinated

Current Management for Disease and Mites in Honey Bee Colonies -
Dr. Medhat Nasr, Research Apiculturist, OBA, Guelph, Ontario

There are a number of known honey bee diseases which can be prevented
or controlled by treatments applied by the beekeeper. Some of these are AFB,
EFB, nosema, chalk brood, and sacbrood.

Recently, parasitic mites were found in North America. Tracheal mites
were introduced to USA in 1984. In Ontario, selective breeding of tracheal
mite resistant honey bees is being done to manage tracheal mites. A bioassay,
known as the quick test, is performed several times a year to screen potential
breeder queens for resistance. Newly emerged workers are tagged and placed
into mite-infested hives. These tagged bees are challenged with tracheal mites
for one week  At the end of the week, the tagged bees are removed and
checked for the presence of tracheal mites. Those that do not have the mites,
or have relatively fewer mites, are considered to be relatively resistant and their
queen is then used for breeding resistant stock. Resistant bee stock is
propagated in areas where controlled mating is practiced. Resistant stock is then
made available for beekeepers to use.

An expansion of this breeding program is underway for the control of varroa
mites. It is thought that certain honey bee traits may be desirable for managing
varroa mites. One of these traits is the hygienic trait. To test for the hygienic
trait, liquid nitrogen is used to freeze-kill capped honey bee pupae. 24 hours
later, the frames are examined to count how many of the freeze-killed
pupae were removed by the honey bee workers. If a high percentage of the
freeze-killed pupae were removed, the bees are considered to be hygienic.
Research results have shown that hygieinc bees were able to detect and
emove pupae killed or damaged by varroa mites. In doing so, varroa mites
would also be removed from the hive. This hygienic trait has been included in
the tracheal mite resistant stock. Another desirable trait is a grooming trait.
Development of a simple test is underway. Sticky boards are used to collect
naturally fallen mites over 24 h and then the mites are examined under the
microscope for damage inflicted by honey bees. The proportion of damaged
mites to naturally dead mites is used to find hives with a high tendency for
grooming. These colonies will be used in breeding.  The grooming trait will be
added to the mite resistant stock in 1999.

Mite resistat honey bee stocks are used in the IPM (Integrated Pest
Management) program which is being developed to control honey bee diseases
in Ontario. The idea is to employ a variety of methods to control the mite
population in honey bee colonies. Thus, beekeepers will be able to decrease the
rate at which chemical resistance occurs and to be more environmentally
friendly. For the control of mites, it is currently recommended that beekeepers
apply formic acid in the spring to control varroa and tracheal mites, use mite-
resistant stock in the late spring and summer, and apply Apistan for varroa mite
control in the fall.

The Small Hive Beetle - David Westervelt,
Bee Inspector, Florida, USA

The small hive beetle is a new predator of honey bees in North America. It has
become quite prevalent in Florida, killing 30,000 colonies of honey bees this
past year. The beetles live in the hive with the bees and reproduce whenever
they are disturbed. The larvae of the small hive beetle feed on bee brood,
honey, and wax. When the colony is infested with beetle larvae, the larvae
produce a slimy material on the combs and the honey bees abscond. It has
been found that the Bayer Bee Strip (coumaphos), used to control varroa in the
USA, is also effective against the small hive beetle. Before the small hive beetle
becomes resistant to coumaphos in the Bayer Bee Strip, other effective
treatments must be found. Pheromone traps or repellents will be tested for
usefulness as a control measure. As it is highly likely that the hive
beetle has already spread to New York  by beekeepers who overwintered their
colonies in Florida, it may only be a matter of time before this beetle is found
in Canada.

Perspectives of Beekeepers and Growers for Summer Crop Pollination
(cucumber, blueberries, squash and pumpkin) - Dr. Peter Kevan/
Svenja Belaoussoff

Recent studies on cucumbers have shown that the greater the distance
between a plant and the hive, the fewer visits the flowers receive from honey
bees. With movement towards mechanized pickers, uniformly-sized
cucumbers are required. Therefore, research must be conducted to find
a way to synchronize pollination throughout a field. Combining cucumber
varieties that bloom around the same time and for a short period with efficient
pollination can help to produce uniform crop.

Highbush blueberries are difficult for honey bees to pollinate because their
flowers are long and narrow. Different types of bees (i.e. bumblebees,
leafcutter bees, honey bees) pollinate different varieties of blueberries,
depending on flower length and width. To increase productivity, studies
must be conducted to find which bees pollinate which varieties. As well, self-
and intervarietal-compatibility must be looked at.

The hoary squash bee is a specialist bee which is seasonally in synch
with squash plants. The squash bee collects nectar and pollen only from
squash plants. A survey of squash bees was conducted last summer in Ontario
and its range was found to be patchy throughout southern Ontario. More
studies are needed to learn about the behaviour and biology of the squash bee
so that it can be introduced into areas where squash and pumpkin are grown,
to enhance pollination.

Further studies need to be conducted on the pollination of cucumbers,
blueberries, and squash and pumpkin so that crop yield can be improved.

Dandelion as a Competitor to Apple Trees for Visits by Pollen-Collecting
Honey Bees - Dr. Terence Laverty/Henry Hiemstra

Dandelion often cover apple orchard floors at a density of 62 heads
per square meter. It has been thought that dandelion competes with apples
for pollination. One hypothetical solution to eliminate dandelion competition
is to bring bees to the orchard after dandelion heads had closed for the day.
Thus, the honey bees would be conditioned to apple blossoms. Another
solution is to mow the orchard floor. To test the first hypothesis, resident and
introduced hives were compared for their pollen collection. Only small
differences were found between them, suggesting that conditioning of the bees
to visit apple flowers first was not significant. Mowing the orchard floor
also had no effect on the per cent of apple pollen versus dandelion pollen
collected. Interestingly, it was found that during peak apple bloom, mostly
apple pollen was collected even though there were dandelion all around. Apple
pollen appeared to be preferred over dandelion pollen. In conclusion, there
was no evidence of competition between dandelion and apple trees for
pollination and therefore no need to remove dandelion from orchards in
southwestern Ontario.

Pollination of Greenhouse Tomatoes in Ontario - Lora Morandin
(MSc. candidate) University of Western Ontario, London, Ontario

In the field, tomatoes are wind-pollinated. In greenhouses, various types of
mechanical vibrators are used instead. In either case, only insects have the
capacity to pollinate male-sterile plants. Manual vibration pollination of
greenhouse crops is expensive, damaging, and time-consuming. As an
equally effective alternative, bumble bees can be used for pollination of crops
such as blueberries, cranberries, tomatoes, and kiwis. These crops are more
efficiently pollinated by bumble bees than honey bees, since bumble bees
vibrate their wings while feeding at flowers and cause pollen to fall from the
anthers. This type of pollination is known as buzz pollination.

A problem with using bumblebees in greenhouses is that they often escape
through greenhouse vents. Bumble bees are sensitive to UV light and are
attracted to the open vents through which UV light enters the greenhouse.
Because UV light cannot penetrate the plastics used in greenhouse walls, the
bees feel confined and this leads to a decrease in their activity and
pollination. Several different plastic types have been tested for UV penetration.
Few types were found to be more suitable for use in greenhouses than what is
already in use. Miniature greenhouses will be built using new plastics to test
for effects on the flight behaviour of bumblebees. It is thought that if new
plastics, which allow the penetration of UV light, are used in greenhouses,
both problems will be solved. The bumblebees will not be able to differentiate
between the vents and plastic and therefore, the bumblebees will not be able to
escape so easily. As well, the bees will feel like they are in an open
environment and so activity and pollination will increase.

Panel Discussion of Pollination Issues - Doug McRory

Many growers require honey bees for pollination their crops. Beekeepers have
started this promotion campaign to increase use of honey bees for pollination
and to encourage growers to rent their bee colonies, but will beekeepers be
able to meet the demand?

There should be standards set for honey bees made available for pollination.
How will the standards be measured, and who will enforce these standards?

It should be emphasized that insecticides sprayed on crops can kill honey bees.
Even if one grower does not spray, his or her neighbouring grower might and
this will harm the honey bees, disrupt pollination, and, therefore, decrease crop
yield.

Should there be contracts between growers and beekeepers? Insurance?
Contracts will help both beekeepers and growers to specify their requirements
and needs in an agreement. Provision of the bees and payment for pollination
services will improve. If everything is agreed upon beforehand, there should
be fewer disputes afterwards.
Medhat Nasr, Ph.D.
Research Scientist,
Ontario Beekeepers' Association
Dept. Environmental Biology
University of Guelph
Guelph, Ontario, Canada
N1G 2W1
Tel: (519) 824-4120
Fax:(519)837-0442
e-mail: [log in to unmask]

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