Biopesticides have been the darlings of organic growers and gardeners for some time now. And, promoted by biopesticide makers such as AgraQuest, they are increasingly finding their way into mainstream farming.

Last year, global sales of synthetic pesticides were about $30 billion, estimates Gautam Sirur, principal consultant at Cropnosis, a Scottish market research firm.

In contrast, the market for pesticides produced through a combination of fermentation and chemistry techniques was about $800 million. The category includes products such as Dow Chemical's Spinosad, which controls foliage-feeding insects, and avermectin, an antibiotic that is also used for insect control.

Valued at nearly $1 billion were fermentation-based bactericides and fungicides, such as those from AgraQuest. And a smaller group of biopesticides, valued at about $200 million, consists of natural extracts, including toxins from the bacterium Bacillus thuringiensis for caterpillar control and rotenone and pyrethrum for insect control.