78. How do pesticides affect bees?

Pesticides are widely used in gardens, farms, and public spaces to control pests and weeds. While they can be helpful for protecting plants, they can also have unintended effects on honeybees.

For a beekeeper, understanding these effects is important—not to cause alarm, but to help you protect your colony with simple, practical steps.

What are pesticides?

Pesticides are chemicals used to control unwanted insects, weeds, or fungi. They include:

• Insecticides (target insects)

• Herbicides (target weeds)

• Fungicides (target fungal diseases)

Of these, insecticides are usually the most harmful to bees, as they are designed to affect the nervous systems of insects.

How do bees come into contact with pesticides?

Bees are exposed to pesticides mainly while foraging.

As they visit flowers to collect nectar and pollen, they may come into contact with:

• Sprayed chemicals on crops or garden plants

• Contaminated nectar and pollen

• Water sources containing chemical residues

Sometimes, exposure is immediate. At other times, bees carry small amounts back to the hive, where it can affect the whole colony.

Immediate effects on bees

In some cases, pesticide exposure can cause rapid and visible harm.

You may notice:

• Large numbers of dead bees near the hive

• Bees twitching or unable to fly

• Disoriented behaviour, such as wandering aimlessly

These signs often appear suddenly and can be distressing to see.

Subtle, long-term effects

Not all pesticide exposure is obvious. Small amounts can still affect bees over time.

These subtle effects may include:

• Reduced ability to navigate back to the hive

• Lower foraging efficiency

• Weakened immune systems

• Reduced queen egg-laying

Over time, these small changes can lead to a gradual decline in colony strength.

Effects on the whole colony

A hive works as a single, organised unit. When foraging bees are affected, the entire colony can suffer.

Possible impacts include:

• Less food being brought into the hive

• Poor brood development

• Increased vulnerability to pests and diseases

In severe cases, repeated exposure can contribute to colony loss.

What can a beekeeper do?

While you may not be able to control all pesticide use in your area, there are practical steps you can take.

1. Choose your hive location carefullyPlace hives away from heavily sprayed agricultural areas if possible.

2. Talk to neighbours and local growersA friendly conversation can go a long way. Many people are willing to:

• Spray in the evening when bees are less active

• Avoid spraying flowering plants

3. Provide clean waterA nearby water source can reduce the chance of bees drinking from contaminated areas.

4. Maintain strong coloniesHealthy colonies are more resilient and better able to recover from stress.

A balanced view

Pesticides are part of modern life, and not all use leads to harm. The goal is not to worry constantly, but to stay aware and take sensible precautions.

By understanding how pesticides affect bees, you can make small adjustments that have a big impact. Over time, this awareness helps you become a more confident and thoughtful beekeeper—one who works with both bees and the wider environment.