Imidicloprid & Pollinators: FAQ


OHP Inc. led the introduction of the neonicotinoid class of chemistry in the U.S. ornamental market with the launch of Marathon® 1% Granular (imidacloprid) in 1994 followed by Marathon® 60W and Marathon® II in 1996 and 2000, respectively. Since then, OHP has added imidacloprid-based Discus® N/G and Discus® Tablets to its product portfolio.


Many questions have recently come up on the use of neonicotinoids and their impact on honey bees and other pollinators. The following are brief answers to some of the most common questions we have received from growers to clarify what is currently known on the issue.


Does the use of neonicotinoid insecticides result in a reduction of honey bee populations?
Current research indicates that no single factor can explain and account for the current honey bee losses, also known as colony collapse disorder. Several studies indicate that bee health is affected by many factors including parasites, microbial diseases, inadequate diet, and even climate change. Many in the scientific community believe the Varroa mite and the viruses transmitted by this pest are the main contributing factors affecting honey bee colony health.
Are there fewer honey bees today than in the past?
Despite news to the contrary, the overall number of managed honey bee colonies worldwide has increased over the last 50 years, not decreased. In a normal honey bee colony life cycle, some 2,000 honey bee workers will leave the hive each day and may die of natural causes. The colony is maintained by newly hatched bees that restore colony numbers.
Can I still use Marathon or Discus on my hanging bas- kets and other spring plants?
Yes, nothing has changed in terms of regulations. You may use Marathon and Discus as you always have whether drenching or foliar-applying baskets and other plant material in the greenhouse, provided you follow label directions.
Does imidacloprid move into a plant's pollen and nectar?
Dr. Carlos Bográn, OHP Technical Manager, notes: "Yes, current research indicates that imidacloprid does get into pollen and nectar but field realistic concentrations in both are too low to cause negative effects on honey bee colonies."
Can I still apply Marathon or Discus N/G as a foliar spray outside on my mum crop or other outdoor crops?
Yes you can, but please be aware that there are some label changes coming in the future with regard to honey bee protection. Marathon, Discus, and most other neonicotinoid insecticide labels will include a "Bee Box" which warns against foliar spraying outside when bees are foraging on a flowering crop, typically in the morning hours. There will be some additional bee protection language on the labels; the Bee Box will be included on most neonicotinoid products manufactured after Feb. 28, 2014.
What do I tell a customer who asks me if the plant they're purchasing has been treated with a neonicotinoid insecticide?
If the plant in question has been treated, you can tell the customer that yes, you have used a neonicotinoid insecticide at permitted doses but no, it does not pose a threat to foraging bees or other pollinators. Only direct sprays to the insect itself (such as a honey bee) pose a direct threat. Application of any insecticide, including neonicotinoids, directly to foraging bees may result in death. Always read and follow insecticide label directions to minimize risks to honey bees and other pollinators.