Pollination.

The insect kept alive sets the limit on everything sprayed

A greenhouse excludes insects deliberately and then introduces one on purpose. Tomato and several other fruiting crops are pollinated by bumblebee hives placed in the house, and without them fruit set has to be done by hand — historically with a vibrating wand, plant by plant, at a labour cost that no commercial operation would now accept. The hives are cheap; what they replace is not.

The mechanism is specific to the flower rather than general. A tomato flower holds its pollen inside anthers that release it only when shaken at the right frequency, which a bumblebee does by gripping the flower and vibrating its flight muscles. Honeybees do not perform that behaviour, which is why bumblebees rather than honeybees are standard under glass. The visible bruising a worked flower shows is the grower’s evidence that pollination is happening at all.

The consequence for crop protection is the part most often left out. A colony living permanently in the crop means every product applied has to be compatible with it, so the pollination decision constrains the chemical options for the whole season rather than for the day of application. That constraint pushes hard toward selective products and toward the biological control that IPM prefers anyway — the pollinator and the predator want the same restraint, which is a useful alignment rather than a coincidence.

It also ties pollination to climate. Bumblebee activity depends on temperature and humidity, and a house that is too hot, too still or too dry sees foraging drop before anyone notices the fruit set has, so a pollination problem often turns out to be a climate problem. DutchGreenhouses® designs the climate, screening and crop-protection strategy so the pollinators stay active and the products used stay compatible with them. Get in touch to discuss pollination for your crop.