Seed germination characteristics and control options for Noogoora bur (Xanthium strumarium) in commercial maize production

Noogoora bur (Xanthium strumarium) is a large, herbaceous, highly competitive annual weed which is subject to Pest Plant Management Strategies in Waikato and Bay of Plenty. A study with scarified burs showed that most plants emerged from 0-40 mm and none from 100 mm depth. Plants emerged after 8 days from 0-30 mm, after 14 days from 90 mm and continued to emerge over summer, with some also germinating in the second year. Cultivated fallow resulted in germination of similar numbers of seeds over two growing seasons with no new seed input. Burs placed buried in a silage stack for 14-84 days failed to germinate in the laboratory. Results from a field trial showed that dicamba and atrazine, alone or in combination with other products, provided excellent control of this weed in maize crop. The herbicide topramezone was also very effective and it also controlled other broadleaf and grass weeds.