Cleavers — Galium aparine — have long caused problems to oilseed rape growers, due to the competitive nature of the weed and the way it can grow across the canopy late in the season. Cleavers are widespread throughout all arable areas of the UK.
Mature cleaver plants can become very large and use the crop for support by growing vigorously across the canopy, ultimately causing serious harvesting problems. Cleavers are very competitive with the crop, depriving it of nutrients, water and light. In non-competitive crops, one cleavers plant per square metre can result in a 5% yield loss.
Inclusion of metazachlor and/or propyzamide in the treatment program can have an effect on cleaver populations, but either of these approaches used alone are unlikely to have a major impact on survival of cleaver plants.
Products to control cleavers in oilseed rape