Southeastern U.S. Vegetable Crop Handbook - 2023 - 24

flowers may not contribute greatly to pollination. Honeybees
and bumblebees move frequently from one flower to another and
placing hives of these bees into a crop at the correct time will
greatly enhance pollination. Even though bumblebees and other
species of wild bees are excellent pollinators, populations of
these native pollinators usually are not adequate for large acreages
grown for commercial production. Colonies of wild honeybees
have been decimated by Tracheal and Varroa mites, and possibly
other environmental factors, and therefore cannot be counted
on to aid in pollination. One of the best ways to ensure adequate
pollination is to keep or rent strong colonies of honey bee from a
reliable beekeeper. Another option for pollination is the bumblebee.
Bumblebees are becoming a popular grower's choice over
the past decade and are being found to be effective as a pollinator
alternative to honeybees. Commercial bee attractants are available
but have not proven to be effective in enhancing pollination.
Growers are advised to increase numbers of honeybee or bumblebee
colonies and not to rely on such attractants. Suppliers of both
honeybee and bumblebee colonies need ample notice prior to
when the bees are needed for a given crop. Approximately 3 to 4
months advance notice is usually sufficient to meet crop pollinator
needs. A written contract between the grower and beekeeper/
supplier can prevent misunderstandings and, thus, ensure better
pollinator service. Pollinator contracts should specify the number
and strength of colonies, the rental/purchase fee, time of delivery,
and distribution of bees in the field.
Honeybee activity is determined to a great extent by weather
and conditions within the hive. Bees rarely fly when the temperature
is below 55°F. Flights seldom intensify until the temperature
reaches 70°F. Wind speed beyond 15 miles per hour seriously
slows bee activity. Cool, cloudy weather and threatening storms
greatly reduce bee flights. In poor weather, bees foraging at more
distant locations will remain in the hive, and only those that have
been foraging nearby will be active. Ideally, colonies should
be protected from wind and be exposed to the sun from early
morning until evening. Colony entrances facing east or southeast
encourage bee flight. The hives should be off the ground and
the front entrances kept free of grass and weeds. For best results,
hives should be grouped together. A clean water supply should be
available within a quarter mile of the hive.
The number of colonies needed for adequate pollination
varies with location, attractiveness of crop, density of flowers,
length of blooming period, colony strength, and competing
blossoms of other plants in the area. In vine crops, recommendations
are one to two colonies per acre, with the higher number
for higher density plantings. Each honeybee hive or colony
should contain at least 40,000 - 50,000 bees. Eight or more bee
visits per female flower are required to produce marketable fruit.
Bumblebees have some advantages compared to honeybees in
that the former fly in cool, rainy, and windy weather and often
visit flowers earlier in the morning than honeybees. Bumblebees
are also active later in the day when temperatures cool and they
have a larger body size than honeybees, thus requiring fewer
visits to achieve good pollination and fruit set. Bumblebee hives
are sold as a quad or four hives per quad. A quad is the minimum
order that can be purchased from a supplier. Generally
one bumblebee hive contains 200 to 250 bees and is equivalent
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to one honeybee hive; however, research that can specifically
document this is lacking. Thus, one quad of bumblebees would
provide good pollination for four acres of a cucurbit crop if the
recommendation is to use 1 bumblebee hive per acre. In some
instances, two hives per acre or more may be recommended (i.e.
triploid watermelon). In this case, one quad would provide good
pollination for two acres. Bumblebee hives should not be placed
in direct sunlight so that the bees work more efficiently. No more
than two bumblebee quads should be placed in one location so
that pollination is more uniform in the field. The quad locations
should be at least 650 to 700 feet from each other.
Insecticides applied while a crop is in bloom pose a serious
hazard to bees visiting flowers. If insecticides must be applied,
select a product that will give effective control of the target pest
but pose the least danger to bees. Apply these chemicals near
evening when the bees are not actively foraging and avoid spraying
adjacent crops while bees are active. If insecticide spraying
is necessary, give the beekeeper 48 hours of notice of when you
expect to spray so that precautions can be taken. Avoid leaving
puddles of water around chemical mixing areas as bees may pick
up and be harmed by insecticide contaminated water. As with
honeybees, one must carefully plan when to spray insecticides so
that the bumblebees are not injured or killed. Because bumblebees
are most active from dawn until late morning, and again
from about 4 PM until sunset, the hives need to be closed around
11 AM so that the bumblebees remain in the hive and are protected
during a late evening spray application.
HOW TO IMPROVE PEST CONTROL
Failure to control an insect, mite, disease, or weed pest is often
erroneously blamed on the pesticide when the cause frequently
lies elsewhere. Several common reasons for failure to achieve
control are the following:
1. Delaying applications until pest populations become too large
or damage is too advanced.
2. Poor coverage caused by insufficient volume, inadequate pressure,
or clogged or poorly arranged nozzles.
3. Selecting the wrong pesticide for the target pests.
4. Contaminated or high pH water source.
SUGGESTED STEPS FOR MORE EFFECTIVE PEST
CONTROL:
1. Scout fields regularly. Know the pest situation and any buildups
in your fields. Frequent examina tions (at least once or
twice per week) help determine the proper timing of the next
pesticide application. Do not apply a pesticide simply because
a neighbor chooses to do so.
2. Integrated Pest Management (IPM). Use an ongoing program
of biological, physical, cultural, and chemical methods in an
integrated approach to manage pests. IPM involves scouts visiting
fields to collect pest population data. Use this updated information
to decide whether insecticide applications or other
management actions are needed to avoid economic loss from
pest damage. Control decisions are based on factors such as:
2023 Vegetable Crop Handbook for Southeastern United States
Southeastern U.S. Vegetable Crop Handbook - 2023

Table of Contents for the Digital Edition of Southeastern U.S. Vegetable Crop Handbook - 2023
