Tech Notes

Bees, hornets and wasps: Why they sting and how to protect the public

By Eric Paysen, Technical Services Manager, Syngenta Professional Pest Management

Bees, hornets and wasps are generally considered beneficial insects. This is especially the case with domesticated honey bees that pollinate much of our food supply. Hornets and wasps serve a much less well-known function as predators of many other pest insects and arachnids. While preventive management of bees, hornets and wasps is seldom warranted on a large scale, there are certain situations in which their removal is necessary.

It is instinctive for bees, hornets and wasps to sting people as a defensive reaction when they live together in social colonies. Examples of social hymenoptera include honey bees, bumble bees, yellow jackets, hornets and paper wasps. These groups are prone to defend aggressively because they gather resources and rear brood in large quantities, both of which represent significant food sources for mammals.

Yellow jackets construct large colonies where developing young could be a protein source for a hungry raccoon or skunk. Yellow jackets and Africanized honey bees are examples of notoriously aggressive social hymenoptera and are quick to defend their colonies from even the slightest vibrations.

Conversely, some bees and wasps are solitary and include mud daubers, carpenter bees, digger wasps and cicada killers among many others. These insects live independently and may provision nests where eggs have been deposited. The nests are less extensive and not as heavily protected. These groups of insects are not typically triggered by vibrations or proximity to nests like the social wasps, but when directly provoked, are capable of delivering a painful sting. Most importantly, the potential recipient of a sting only has to contend with one angry wasp versus an entire colony (hundreds to thousands) of social wasps.

As a pest management professional (PMP) it is important to assess each stinging pest situation individually. In situations where risk is low, such as migrating swarms of honey bees, the best control tactic might include caution tape and monitoring the situation until the swarm has moved to a less populated area.

With established colonies of social bees and wasps, a stronger control tactic may be necessary. Early detection in the spring and elimination is best because as colonies grow throughout the season, they only become more aggressive and dangerous.
Before beginning any removal of a colony, be sure to secure the area with caution tape and signage at a minimum, and always wear protective equipment when treating. Given wasps and bees will likely be in full defense mode, the temporary closure of structure entrances and exits may be necessary.

Applying product directly into the entrance of the hive or nest is the most effective removal strategy. Hornets have a single entrance at the bottom of the paper-like, egg-shaped nest, while yellow jackets typically have a single entrance in the ground or other void. Honey bee colonies can have multiple entrances in natural or often man-made voids like walls and attics.

There are a few different treatment options that can effectively control stinging pests. As the industry standard for decades, synthetic pyrethroids like those found in Demand® CS insecticide are well known for fast knockdown in challenging situations. Liquid neonicotinoid insecticides, such as Optigard® Flex liquid insecticide and Tandem® insecticide provide an intoxicating effect to wasps, hornets and yellow jackets, which inhibits their aggressive alarm response. This option provides effective control and an added level of safety for customers, PMPs and the public.

Please contact your local-area Syngenta sales manager if you have questions about Demand CS, Optigard Flex, Tandem or other products labeled for control of stinging pests.
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©2019 Syngenta. Important: Always read and follow label instructions. Some products may not be registered for sale or use in all states or counties and/or may have state-specific use requirements. Please check with your local extension service to ensure registration and proper use. Demand®, For Life Uninterrupted™, Optigard®, Tandem® and the Syngenta logo are trademarks of a Syngenta Group Company. Syngenta Customer Center: 1-866-SYNGENT(A) (796-4368).


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© Syngenta. Important: Always read and follow label instructions. Some products may not be registered for sale or use in all states or counties and/or may have state-specific use requirements. Please check with your local extension service to ensure registration and proper use. The trademarks displayed or otherwise used herein are trademarks or service marks of a Syngenta Group Company or third parties. Syngenta Customer Center: 1-866-SYNGENT(A) (796-4368).