Controlo de cana (Arundo donax) em zonas ribeirinhas

Abstract

Giant reed (Arundo donax) is a tall perennial grass widespread throughout the Mediterranean region. Despite its use to make musical instrumentals, building material, erosion control, windbreak, and renewed interest in bioenergy production it become a major invasive weed problem in watersheds because of its high competitive ability. Here, the biology and identification of giant reed and related species, e.g. common reed (Phragmites australis) and the weed negative effects are revised. Giant reed once established leads to loss of biodiversity. It also interferes with rivers by increasing sedimentation and narrowing water channels causing flooding, damage to bridges and stream bank erosion and increased costs of management. The management strategies are also revised. Finally the case-studies of giant reed control in Portugal are presented. Giant reed growth can be suppressed by repeated mowing combining with chemical control. This requires treating the weed with a systemic herbicide at appropriate times of the year to ensure translocation to the roots and rhizomes. Glyphosate (2.5% to 5% of commercial solution with 360 g a.i./L) applied after flowering showed to be effective but repeat applications, at least during two to three years, will likely be necessary. Cut-chemical stem treatments (humectation) were also effective if glyphosate (75%) is applied within few minutes of cutting the stem