Reduction of purple loosestrife establishment in Minnesota wetlands

Examined whether establishment of Lythrum salicaria through recruitment from seed banks can be reduced by use of either 2,4-D herbicide or competitor plant species. These approaches were evaluated with soil collected from two Minnesota wetlands and maintained in outdoor flats where water levels were controlled. In flats, application of 2,4-D to seedling communities reduced loosestrife frequency and population density by 44 and 94%, respectively. Application of 2,4-d also reduced dicot species richness. In flats, seeding of Italian ryegrass Lolium multiflorum reduced loosestrife seedling density by 72% in one but not both years of the study. In wetlands where water levels were uncontrolled, 2,4-D applied to field quadrats reduced loosestrife seedling density by 78%. Managers should minimize seed bank development by attempting to eliminate recently established populations of scattered plants before they attempt to control long-established, monodominant stands. -from Authors