Biological crop protection: it's tricky but possible

Integrated pest management is a complex process that takes each farm's uniqueness into consideration. With growing support from all spheres, biological solutions are gaining traction.

- Lindi Botha

"Ah, there goes a butterfly. That's a good sign," says André du Toit, general manager of Kleinberg Kriegler Farms in De Doorns in the Western Cape. He is standing between his vines where table grapes are produced using an integrated pest management (IPM) programme.

This relies on synthetic chemicals for crop protection early in the season, moving to biological products later to ensure the produce meets maximum residue level (MRL) regulations and to reduce the negative impact of the former on the ecosystem.

The presence of insects like bees and butterflies bodes well for the farm - it indicates that pesticide levels are in check, rather than being so abundant nothing can survive. Achieving this balance between pests and beneficial insects is, however, no mean feat, but one that is certainly becoming easier to pull off.

"The developments taking place regarding biological pest control have been really exciting," says Du Toit. "We're able to achieve 100% control of mealybug using an IPM programme, which means we meet MRL regulations while nurturing the natural resources of the farm.

"At the start of the season, we use a systemic insecticide to get a knockdown effect on mealybug. Once fruit is nearing harvest, we send in parasitic wasps, which takes care of any remaining mealybugs but obviously does not result in a chemical residue on the fruit.

Considering that mealybug can wipe out 30% of your yield, it's a huge advantage to have effective, robust tools like these," he explains.

Kleinberg Kriegler has been using biologicals since 2000. Du Toit notes the progress in the industry: "Ten years ago, around 40% of our crop protection a month before harvest would have been biological. Today, it is just over 80%."

THE RIGHT APPROACH

Such success bodes well for the industry.