As most people in our industry are probably well aware by now, there has been a large and, at times, vocal concern raised over the use of neonicotinoids in the greenhouse industry and within all areas of agriculture. This concern revolves around three separate but somewhat related subjects: bee decline, colony collapse disorder and pollinator deaths due to both acute and chronic exposure to pesticides.
A brief review of the development and use of neonicotinoid products shows that these products were approved by the Environmental Protection Agency (EPA) and first used in the mid 1990s. Through the introduction of these products, the pesticides that were replaced were not only less effective in many cases, but also potentially more dangerous to humans and the environment. The neonicotinoids are systemic materials that are absorbed by the plant and move through it to provide effective pest control. Studies have shown that when mixed and applied properly, these materials are safe to humans and pollinators.
Logically, as with all insecticides, these products are toxic to honeybees and other pollinators if not used properly. Directions by the manufacturer need to be followed correctly and all responsible steps taken to protect beneficial and non-targeted creatures from exposure to these products when applications are made. Furthermore, studies have shown these chemicals can be transferred into the pollen and nectar of treated plants. Pollinators, through the course of their contact with blooms on treated plants, can then be exposed to any tainted pollen and nectar.
Laboratory studies have shown that honeybees and bumble bees exposed to high sub-lethal levels of these products can experience problems flying, navigating, learning new tasks and experience reduced food consumption. But, if proper application rates are applied, no studies have shown acute or chronic toxicity to pollinators if levels were even detectable. To date, no effects have been observed in field studies with field realistic dosages. Also, to date field trials in comparison to laboratory studies have shown no negative effects from chronic exposure to neonicotinoids again when applied at recommended rates and application methods.
Where Does Our Industry Fit Into The Discussion?
The question before all of us now is, where does the commercial horticulture industry fit into the discussion of neonicotinoid use and its effect upon pollinators? Do the plants we grow for personal and commercial landscaping purposes in any way harm these creatures? It is again my hope that all applicators first read each pesticide label closely before treatments are made and then follow recommendations as listed. With correct use as listed by the manufacturer and approved by the EPA, we as growers can be both successful in our crop production and good stewards of our environment.
As I think about the possibility of actual chronic insecticide exposure to honeybees and other pollinators, I have a few questions. Can exposure to or ingestion of nectar and pollen from greenhouse-grown flowering plants treated with neonicotinoids harm pollinators? If so, why have only laboratory trials produced confirming results and not actual field trials?
Having owned two honeybee hives when I was younger, I have a fairly good background in the nature of honeybees. Recently I also conducted a quick search of bee facts. Here are some interesting facts that I would like to share:
• The average honeybee colony consists of 50,000 bees. Of that population, there is one queen, 50 to 100 drones (males) and the remainder of the population are the worker bees (non-fertile females).
• The queen lays 1,000 to 2,000 eggs per day to maintain the hives population of worker bees.
• The average life span of a worker bee is four to six weeks during spring/summer.
• On average, 2.5 million flower visits are required by honeybees to produce one pound of honey.
• The average honeybee hive produces 50 pounds of honey per year.
• The average honeybee harvest range in a nonagricultural setting is 2 miles.
After reviewing these facts, I have some compelling doubts about the impact any greenhouse-grown flowering plants treated with neonicotinoids may have on the overall health of honeybees. If we assume, and hope, the plants were treated properly with these materials at the greenhouse, and if any chemical was transferred to the pollen and nectar, it would be at very low, nonthreatening and EPA acceptable levels. Any direct or indirect exposure to these low, if present, levels would constitute a minimal, sub-lethal exposure that to date even controlled laboratory studies have shown little or no negative effect to the honeybee. Furthermore, considering the natural mortality rate of worker bees at approximately 17 to 20 percent per week in peak flight season, how much of an impact does any low level chronic exposure have upon the bees if such an effect were to even exist?
It has been written that any and all primary food sources for pollinators must be protected from chemical contamination. What constitutes a primary food source, 20 percent of overall hive food supply? If this is the case for honeybees, this figure would equal 10 pounds of honey produced, or the equivalent of 25 million flower visits, and all derived from harvesting nectar from within a 4 square mile urban or residential area. Now I would love to say that our industry is successful to such a point that the density of greenhouse grown and chemically treated plants were at such a density to supply 20 percent of the food needs to all pollinators, but I’m afraid reality does not support the math. Plus again, no studies have shown that responsible use of these products taint any potential food sources.
Where do we go from here?
1) I believe our industry needs to unite and fund research to determine the actual effect, if any, that our greenhouse usage of neonicotinoid products has upon pollinators. This work needs to be conducted in the field, under actual urban and residential situations, and not solely under controlled laboratory conditions.
2) Trials need to be conducted, which reaffirm or adjust the recommended application rates for safe and effective pest protection from the use of these products.
3) All methods and timing of applications need to be studied to determine the safest and optimum techniques of usage. This is especially true in regard to drench applications.
4) Our industry needs to reach out to the environmental groups and express our sincere desire to seriously address this subject. We are all stewards of this earth and need to protect it.
5) When comprehensive facts are determined from actual field trials, we need to supply both the retailer and consumers with the studies facts and guidelines that have been determined for ensuring the safety of our environment.
6) We as an industry must diligently and consistently follow these guidelines for the safe and effective use of these products.
We are all in the business of growing and selling plants that improve the life experience of the citizens in our community. We must continue to offer plants to consumers which are of the quality and value that they have come to expect. But, we must also do so in a manner that does not harm our environment or the pollinators upon which our very food supply depends.