Chemical and mechanical control of the invasive weed Ambrosia artemisiifolia in summer crops

Ambrosia artemisiifolia (common ragweed) is an invasive weed in Europe in both agricultural and non-agricultural areas, in particular along roadsides and in river banks. It is considered an important, noxious weed because of its allergenic properties (rhinitis in humans) and its competitiveness with many crops, and in particular annual summer crops such as maize and sunflower.

In maize, the selective herbicides currently available allow, in general, a good control of ragweed, both with pre-emergence treatments (e.g. with mixtures containing either terbutilazyne or isoxaflutole) and post-mergence treatments (e.g. nicosulfuron and other ALS-inhibitors, mesotrione, dicamba, sulcotrione).

In sunflower, due to a shorter availability of products, pre-emergence treatments with herbicides often need to be integrated with mechanical interventions at 4-6 leaf stage of the crop (e.g. inter-row hoeing and ridging) to get satisfactory control of ragweed. In imidazolinone-tolerant varieties, good results can be achieved by applying imazamox in post-emergence.
Within the EMPHASIS project UNITO elaborated recommendations on selective means of control on summer crops and broad-spectrum herbicides on cereal stubble affected by Ambrosia artemisiifolia as part of the Guidelines for sustainable IPM control of weeds in agricultural and non-agricultural areas.

Correct management consists of applying control strategies to limit further spread in not-infested areas and to reduce its abundance in the infested ones. Spread of the species is favored by the adoption of continuous monocropping or short rotations, which may also increase the risk of selecting herbicide-resistant populations. Early diagnosis of its presence and rapid eradication of all plant parts represent a very efficient way to control this specie. For this reason, increasing of awareness among stakeholders and users play an important role in long-term management of the invasive specie.