Agricultural land carries both great opportunity and serious risk. The same field can fill a hive in a week and poison a colony the next day.

The opportunity

• Density: Uniform flowering over a wide area gives very high yields
• Predictability: Sowing dates are known, so flowering can be forecast
• Single-flower honey: A crop's honey can be harvested separately
• Pollination income

A short, sharp flow

In monoculture the flowering lasts a few weeks, after which the landscape empties completely. The colony passes abruptly from abundance to dearth.

This transition triggers robbing and stores run down quickly. Where the colonies go next must be planned in advance.

Spraying

This is the greatest risk. A foraging bee does not recognise a sprayed crop.

The harm is not limited to direct mortality. Sub-lethal doses can affect orientation, learning and brood development. A bee that cannot navigate does not return; she is not counted as a loss but she is lost.

One-sided nutrition

The pollen of a single crop gives an incomplete amino acid package. A colony dependent on one source for long weakens even though it appears well fed.

Reducing the risk

• Talk to the grower. The single most effective measure; knowing the spraying calendar changes everything
• Close or move the hives on application days
• Provide water so the bees do not drink from puddles in the field
• Document suspected poisoning: Collect the dead bees, record date and location, report it

Signs of poisoning

• Mass mortality in front of the hive
• Trembling bees with poor coordination
• Dead bees with tongues extended
• A sudden loss of foraging force
• The same picture in several colonies at once

Mutual benefit

The relationship is not one-sided; pollination raises yield and quality in many crops.

Explaining this to the grower is the best route to cooperation over spraying. A grower who gains from the bees is more willing to protect them.