Protecting Bees Through Informed Pesticide Choices

In Greenhouse Grower

By Tami Van Gaal

Producing crops to meet consumer quality demands means that growers may use chemicals to control pests and diseases. Some of these products may be harmful to bees if used incorrectly. To demonstrate good environmental stewardship, growers need an understanding of the issues presenting risks to bees and of strategies to minimize the risks. Knowing where to find key product information and how to interpret it can help growers make sound choices regarding the application of effective products.

The Importance Of Pollinators To Our Food Supply

Insect pollinators, including bees, are important to our food supply system, both in terms of economics and of production. Pollination by bees alone contributes to more than $15 billion in crop value annually [1]. Many crops require biological pollination, including fruit, nut and vegetable crops. Undoubtedly, our grocery store shelves would look quite different without bees pollinating our crops.

Understanding Colony Collapse Disorder

Concern about bee health is widely publicized, due in large part to our dependence on bee pollination for food production. Currently, much research and attention is focused on Colony Collapse Disorder (CCD). CCD describes a syndrome in which an unexpected, sudden loss of overwintering adult bees occurs in a mature colony, though the queen and brood generally survive [1]. These colonies are drastically weakened by the loss of the adults. Not all colony losses are attributed to CCD. CCD is diagnosed when colony loss is noted in the absence of dead bees, implying that the bees did not return to the hive [3].

Multiple factors contribute to CCD, though the exact mechanism is not well understood. Among the factors believed to play a role are:

• Parasites: The Varroa destructor mite is found in association with CCD hives and is considered to be a serious threat to honeybee health.
• Pathogens: CCD hives have greater numbers of pathogens present [4], including Nosema fungal infections. Viral infections are also correlated with CCD, including systemic Tomato Ring Spot Virus [5].
• Varroa/Nosema disease complex: Interactions between parasite and pathogen are suspected [6].
• Hive management: Concerns range from strong reductions in genetic diversity to the impact of long-distance transport of hives for pollination services.
• Pesticide toxicity: In previous decades, concern focused on risks from the use of organophosphates and other classes of pesticides. Recent concern has focused on the neonicotinoid class of chemicals.
• Habitat loss: Expansion of agriculture, changing agricultural practices (elimination of wind rows and buffer strips) and housing has led to a reduction in native and wild areas, which serve as rich sources of food for foraging bees.
• Hive nutrition: Nutrition is often provided in the form of commercial foods.

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SIPMC Disclaimer: Colony Collapse Disorder is caused by a number of factors. This article focuses on ways that growers can reduce risks to pollinators through one of those factors.