Blinking in the blazing Brazilian sun, a farmer looks up at the sound of an aeroplane, flying low over his sugarcane plantation in Sao Paulo.
A hatch suddenly opens, and a white cloud emerges.
It may look like pesticide, but these are live eggs falling down - from wasps.
Once hatched and grown, the insects inject their own eggs into those of the sugarcane borer - a moth that in its caterpillar stage eats valuable plants - preventing the pest from hatching.
A number of farmers in Brazil have swapped chemicals for wasps, in a country that has recently outgrown the US as the largest consumer of pesticides.
The biotechnology firm that is fighting nature with nature - what is known as biocontrol - is Bug Agentes Biologicos, or simply Bug, based in Piracicaba, Sao Paulo.
Egg-spraying from a plane is just a trial - at the moment, the wasps' eggs are put on pieces of cardboard and distributed throughout the field. But Bug wants to start using a plane later this year, once the technology is more reliable.
Bug mass-produces Trichogramma galloi, a breed of wasps able to parasitise moth eggs. One wasp can lay its eggs in more than 50 moth eggs in its short life of up to two weeks.
Last year, the firm made it on to the list of the world's top 50 most innovative companies, compiled by US business magazine Fast Company. Forbes called it one of Brazil's top 10 most innovative firms.
The technique isn't new - but the main innovation is in breeding the wasps on an industrial scale.
They are very specific, only multiply in eggs of butterflies and moths, [and do] not cause harm to humans or plants, says Bug's director, Diogo Rodrigues Carvalho.
According to the company, in the past two years, Bug has treated an area of 500,000 hectares (5,000 sq km) of sugarcane in Brazil.
Biocontrol is an area of biotechnology that involves moving away from toxic chemicals, either by mass-producing a pest's natural enemy or by introducing an exotic species to attack the pest.
Currently, biocontrol is receiving a lot of attention, says Dr Toby Bruce of Rothamsted Research in the UK.
It is increasingly important as EU legislation is restricting the use of conventional pesticides, he says.
Consumers are demanding chemical-free products, and pests are continually evolving resistance to the pesticides currently available.
[Also,] many pesticides are broad spectrum and kill the natural enemies of the pests as well as the pests themselves.
