Photo: Vosnesensky bumble bee (Bombus vosnesenskii) via Flickr/USGS Bee Inventory and Monitoring Lab, public domain.

Many of us do not remember this tragic event. Maybe we never even heard about it in a world where today’s tragedy is usually relegated to history by tomorrow.

During National Pollinator Week in June 2013, at a shopping center parking lot in Wilsonville, Oregon, up to 100,000 Vosnesensky bumble bees (Bombus vosnesenskii) were killed in what has been documented as the largest pesticide die-off of bumblebees in North America. Vosnesensky bumble bees are common along West Coast USA.

This awful tragedy was revisited recently, as the neonicotinoid pesticide dinotefuran, which was responsible for the bumble bee deaths that day, is once again being analyzed in the June journal Environmental Entomology. This widely used family of pesticides is lethal to pollinating insects.

The bees that died belonged to almost 600 colonies. There is no knowing how much harm was caused to those colonies due to the loss of those bees. Besides death, bees can also be severely damaged from the pesticide in several ways biologically, and reproduction can be drastically reduced.

The 55 blooming little leaf linden trees were sprayed that fateful day due to an aphid infestation. The aphids were no threat to the bees but were messing up the parked cars beneath the trees. Many bees were drawn to the flowering trees, which were sprayed while bees visited the blossoms.

This 1:18-minute video by KOBI-TV NBC5 covers the 2013 bumblebee tragedy:



In essence, the Oregon agriculture department ruled harshly against the applicator. Oregon banned the use of neonicotinoid pesticides on linden trees after the bumblebee kill of 2013. The pesticide was found to have been incorrectly applied and was prohibited from being applied to flowering parts of plants.

According to the new paper, recent research implies there is no good safe time of year to apply systemic neonicotinoid pesticides to trees and shrubs to avoid sublethal or lethal effects on bees. Systemic means the poison seeps into plant tissue so the plant itself, including its nectar and pollen, is toxic to insects.

Most studies concerning pesticide impact are carried out concerning honeybees rather than wild bees such as bumble bees even though the bumblebee is a talented and important pollinator, second only to the honeybee as an agricultural and wild plant pollinator.

It is so important that we make healthy plants available to bumblebees and all wild, native bees as well as honeybees. Please do not use pesticides on your plants, look for natural solutions to garden problems. If you buy potted plants, find out if they were sprayed, and if so, with which substances. Let's help our pollinators stay alive and thrive.