Hungry pests cost farmers millions in crops losses each year, resulting in the widespread use of plant protectants, to which many bugs eventually become resistant.
But one effective deterrent is clean, green, and sustainable - the wasps, flies, ladybirds, and other predators that happily feast on crop pests.
Growers are making better use of this natural pest control using plants that attract pest predators.
Inviting pest predators might also save money. The US EPA estimates that farmers spend more than $30 billion a year on pest control - and the cost continues to climb.
Yet pests still wipe out more than a third of potential crops. In addition, more than 500 pest species have developed resistance to chemicals that once kept them in check.
Previous studies had shown that diverse landscapes promote bigger populations of pest predators. But it's tough for farmers to evaluate just how much pest control such predators actually provide.
Surveys can't really tell the whole story. If a field has low pest numbers, are predators keeping them in check, or did the pests just not show up there?
A recent US study shows that natural pest control is boosted 4 to 5 times when predator populations are booming in more diverse landscapes.
The studies also showed that predators tend to arrive in farm fields a bit later in the growing season.
This suggests that farm habitats may not be able to hold aphids in check early on so other controls are needed to prevent damage to young crops.
Source : National Geographic - 12 August 2009