WOOSTER, Ohio -- Insecticides may be the only effective means to control the soybean aphid, but what can stop the pest may also be harmful to beneficial insects, such as honeybees.
With soybean aphid populations rising, and concerns growing that spraying for soybean aphids can injure and kill honeybees that come into contact with the chemical, Ohio State University Extension educators are working hard to make farmers more aware of the potential dangers and to help improve communication between beekeepers and growers.
Jim Tew, an OSU Extension apiculture specialist from the Honey Bee Lab at the Ohio Agricultural Research and Development Center, said honey bee exposure to treated soybean fields is, for now, not a major issue, but he still sees education and communication as an important step to making sure it doesn't become a major problem.
"We want beekeepers to understand that soybean growers need to spray to protect their crop and we want soybean growers to realize that there may be beekeepers in the area whose colonies may be vulnerable to spray drift or treated soybean fields," said Tew. "It's important that both groups recognize not only the challenges each one has, but also the contributions that both industries have in Ohio agriculture.
While soybean production is a $1 billion-a-year industry in the state, beekeeping is a small, yet thriving aspect of agriculture. Ohio has about 15,000 honey-producing colonies, yielding nearly 70 pounds of honey per year. The honeybee is the workhorse of the pollinating world, flying up to three miles from the colony to visit a wide variety of nectar-producing plants, from white clover to tulip poplar to goldenrod. Fortunately, said Tew, flowering soybean plants are at the bottom of the list of a honeybee's food source.
"Historically, Ohio is not one of those states where soybeans are a major nectar source for honeybees. We don't know why, but that's not to say that a honeybee won't check out a soybean plant. If the insect feels the soybean plant is worth the effort, it will use it as a food source," said Tew.
Soybean development is also on the side of the honeybee.
"Most of our soybean aphids will show up after the large migration, which historically has been in the later part of July across the Midwest," said OARDC entomologist Ron Hammond. "Most of our spraying is occuring now. The soybean plant is no longer flowering and is developing pods and filling seeds. We don't have a lot of fields in full bloom unless they are planted late."
Despite both situations, there may be times when bees are inadvertently exposed to chemicals, either through treated soybean fields or via spray drift. The following recommendations are offered to aid in improving the business relationship between soybean grower and beekeeper.
• Soybean growers should follow Ohio Department of Agriculture regulations when handling insecticides labeled toxic to honeybees. According to the ODA, no person shall: "Apply or cause to be applied any pesticide that is required to carry a special warning on its label indicating that it is toxic to honey bees, over an area of one-half acre or more in which the crop-plant is in flower unless the owner or caretaker of any apiary located within one-half mile of the treatment site has been notified by the person no less than twenty-four hours in advance of the intended treatment"; or "Apply pesticides which are hazardous to honey bees at times when pollinating insects are actively working in the target area."
• That being said, beekeepers should register their hives with ODA. "It behooves them to let someone know that they are in an area of intensive soybean production," said Tew.
• Beekeepers should not keep beehives close to soybean fields to minimize exposure to spray drift. Tew recommends at least a mile separation, although bees have been known to travel up to three miles to find sources of food.
• Opportunities may exist for soybean growers to treat their fields in the morning or later afternoon/early evening when bees are less actively foraging for food.
• Beekeepers may be able to close or confine their hives for a short period of time to allow soybean growers to apply chemical applications. However, the state of the hive should be monitored closely, as bees will overheat during the summer if not kept cool and may die under such conditions.
• Soybean growers and beekeepers should communicate on a regular basis. "Communication between growers and beekeepers is necessary to prevent any unnecessary problems," said Hammond.
For more information, contact Jim Tew at (330) 263-3684, or tew.1@osu.edu; Ron Hammond at (330) 263-3727, or hammond.5@osu.edu, or the Ohio Department of Agriculture at (800) 282-1955.