(Updated in March 2020, changes are marked in bold)
Species can carry different mutations which affect SDHIs. A few mutations can lead to different sensitivities depending on the chemical structure of the active ingredient.
As all SDHIs are cross-resistant, resistance management must be the same for all SDHIs. All monitoring and guideline related statements refer to the entire group of SDHIs.
Apply SDHI fungicides always in mixtures
The mixture partner:
should provide satisfactory disease control when used alone on the target disease
must have a different mode of action
- The use of additional, non-cross-resistant modes of action should also be considered (ready-mixtures and tank-mixtures where legally possible)
- Apply a maximum of 2 SDHI fungicide containing sprays per soybean crop (no soy after soy/ double cropping)
- Apply the SDHI fungicide preventively or as early as possible in the disease cycle. Do not rely only on the curative properties of SDHIs, or SDHI-containing mixtures
- Strongly reduced rate programs including multiple applications must not be used. Refer to manufacturers’ recommendations for rates
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 partially resistant soybean varieties, reduce the planting window, give preference to early-cycle varieties and endorse the destruction of volunteers and harvest residues from previous crops such as cotton.
Adhere to the general use guidelines for SDHI-fungicides.
- Apply SDHI always with a mixing-partner. The mixture partner:
- Should provide acceptable disease control when used alone on the target disease.
- Must have a different mode of action (including multisites).
- ready-mixtures and tank-mixtures can be considered as “mixtures” (where legally possible).
- Apply a maximum of 3 SDHI containing sprays per cotton crop, according to the table below.
- Apply SDHI fungicides in a maximum of 2 consecutive applications.
- Apply the SDHI fungicide preventively or as early as possible in the disease cycle.
|Total number of spray applications per crop
|Max. recommended SDHI fungicide sprays in mixture (apply a mac. of 2 consecutive applications)
Good agricultural practices must be considered to reduce source of inoculum, disease pressure and resistance risk, e.g. no multiple cropping, give preference to disease-tolerant varieties and endorse the destruction of harvest residues from previous crops such as soybean.