Plastic and straw are used to cover the ground in strawberry production for protection against weeds, erosion, and moist soil. In Norway, straw is utilized on about half of the areas with open-field strawberries. In some areas, both plastic and straw are used.
Until now, Brazilian strawberry farmers have used plastic as mulch. However, inspired by the extensive use of straw in Norwegian strawberry fields, Brazilian researchers have carried out trials in which the use of plastic as compared to a type of organic mulch readily available in Brazil: coffee husks, a by-product of coffee production made from coffee bean shells.
The results, presented in the PhD-thesis of Dr. Fernanda Esteca from Sao Paulo University, whose work has been linked to the integrated pest management (IPM) project Smartcrop at NIBIO, showed that covering the ground in a strawberry field with coffee pulp mulch led to more predatory mites and fewer spider mites in the strawberry plants than when plastic was used for ground covering. The coffee pulp mulch also led to a higher infection pressure of a beneficial fungus that kills spider mites. The two-spotted spider mite is considered a significant pest in Brazilian strawberry production.
The interest in utilizing biological control in strawberry production has increased in Brazil, due to the high market demand for pesticide-free berries, as well as the problems that the indiscriminate use of chemical products has generated.
"There is a need to integrate other management methods, especially biological control", says Fernanda Esteca. "This material is available in big quantities and not expensive, so it is a good economy for the farmers. Some coffee producers actually give it away for free", she adds.
Read the complete article at www.nibio.no.