(Reviewed January 2024; No changes)
QoI fungicides control soybean diseases including rust, which is a major disease in Latin America and has been detected recently in the USA.
In order to ensure sustainable use of QoIs the Working Group recommends:
- Apply QoI fungicides according to manufacturer's recommendations for the target disease (or complex) at the specific crop growth stage indicated. Effective disease management is a critical parameter in delaying the build-up of resistant pathogen populations.
- Use QoIs preventatively or as early as possible in the disease cycle.
- Use QoIs preferably in mixtures (co-formulations or, where permitted, tank mixes) with fungicides from a different cross-resistance group. At the rate chosen, each partner on its own has to provide effective disease control. Refer to manufacturers’ recommendations for rates. In regions where target site mutations in key target soybean pathogens are present mixtures are mandatory.
- Limiting the number of sprays containing QoI fungicides is an important factor in delaying the build-up of resistant pathogen populations.
Good agricultural practices must be considered to reduce source of inoculum, disease pressure and resistance risk, e.g. no multiple cropping, implement and respect soybean-free periods, consider varietal tolerance, reduce the planting window, give preference to early-cycle varieties or endorse the destruction of volunteers.