There isn’t a harder working insect with a symbiotic relationship to humans than a bee. Yet, despite the endless work of these creatures and their role in the human food supply, they face serious challenges to their survival. Some threats include the unintentional consequences of chemical sprays by the very people who rely on the bees for their livelihoods; the fruit growers.
Andony Melathopoulos, assistant professor of Pollinator Health Extension with the Agricultural and Life Sciences department at Oregon State University, is on a mission to help pollinators, and even hosts his own OSU podcast called PolliNation. His work includes helping growers better balance bee health with the need to apply products that ensure better crop health, yields and vigour. Like all balancing acts, it’s no minor task.
All pollinators can be at risk from chemical applications, primarily pesticides, but an increasing number of studies point to fungicides as well. However, it’s generally the diligent honey bee that faces the greatest adversity. The honey bees seen in colonies now, both wild and managed, are descendants of those originally imported from Europe in the 1600s. They’ve been part of food cultivation for a long time, but since the 1980s, concerns about their decline have grown.
“It doesn’t take much to kill the bees,” Melathopoulos says.
Undetermined colony collapse disorders, varroa mite-caused diseases, European foulbrood disease, Asian Giant Hornets and more have plagued the small fuzzy pollinators. The last thing they need is another challenge, but certain fruit-growing practices have unwittingly exposed them to just that. Part of the problem stems from language used on labels.
Understanding what labels mean when it comes to bees
Any chemical label that says “highly toxic” or “toxic” to bees is obviously poisonous to them, but these types of descriptors mean it’s a single exposure that can cause deadly outcomes.
“It’s often a lethal effect,” Melathopoulos explains. “It often looks like piles of dead bees in front of the colony. It has this characteristic bee kill look.”
This type of labelling language is simple enough, but this is where the black and white turns to shades of grey for growers. Bee toxicity information is generally included in environmental hazards or environmental cautions sections, but many older labels haven’t been updated. For newer labels, if there are no cautions, Melathopoulos says this means the registrant has done tests and it appears to not be toxic to bees.
Photo by Andony Melathopoulos
Bee in a cherry blossom
Sometimes the statement “chronic toxicity” is used on older labels, though it’s not common.
“That toxicity can have lingering effects,” he says. “The bees may have a harder time foraging.”
These chemicals may lead to their death, though not in as dramatic a fashion as a highly toxic product.
But what about products that don’t use the word toxic? Might there still be harm to bees when they’ve been sprayed on the plants, and are their lingering effects?
“You’re going to see some mention of this on the label. It’s not as clear and not as direct,” Melathopoulos says. “When you look at the label, you’re going to look for language of whether the product remains toxic if [the bees are] actively visiting or visiting.”
Some labels specify that harmful elements break down after a certain number of hours, which indicates the need to spray at night so bees aren’t active until the chemical is perceived to be harmless. If there is no time range for the breakdown of the product, it can be assumed that it takes longer than eight hours and shouldn’t be applied when bees are visiting or foraging.
“The word ‘visiting’ can often be interchanged with ‘foraging’,” Melathopoulos says. “Don’t apply when bees are actively visiting the treatment area. The word actively suggests that you can… apply it in the evening.”
If the product says “visiting” or “foraging” without the word “actively,”, sprays need to wait until after petal drop. Any time there are flowers, growers need to be very cautious as he says there is a lot of uncertainty about sprays any time plants are in full bloom. He adds that no matter what the product might say, avoid spraying during the day during the full bloom period. Before spraying at night during full bloom, he advises growers to talk to the registrant to ensure residual toxins break down within eight hours.
“Hammer the plants hard before they come into bloom,” he advises. “Try to do your insect pest control while the risk is relatively low.”
If there are flowering weeds in the hedgerow, don’t spray them and be careful of accidental overspray. Save these plants for bees to forage on. Additionally, don’t put colonies at row ends, keep them at a good distance from plants.
“Putting a pallet of bees right up against the crop every 20 meters or 30 meters isn’t going to increase pollination and there’s no way you’re going to be able to protect those last plants without dousing that colony,” Melathopoulos says.
Photo by Ronda Payne
Beehives
Beehives located among sweet cherries in a Fraser Valley orchard.
Another concern is that the term ‘residual’ doesn’t cover whether the toxins in the product are systemically residual. This means that bees may not be harmed from a previous application, but the product may be found in the pollen or the nectar. This is not covered on product labels and has a place in the “risk cup” studies Melathopoulos is working on.
The theory is that bees suffer a cumulative effect from all of the chemicals they come into contact with. However, present-day labelling focuses on a chemical-by-chemical basis and not a cumulative one.
Knowing all the answers to keep bees healthy is a long way off, but understanding product application better is a great start to creating more balance and better pollinator health.
