Erica Pate & Katie Goldenhar
These guidelines were developed to address the presence of anthracnose resistance to group 11 fungicides in Ontario, and the limited products available to growers. This includes the recent changes to the captan label for berry growers including a 6-day REI and a maximum of 6 applications. Thanks to everyone who provided input into these suggestions.
In Ontario, strawberry anthracnose has been confirmed resistant to pyraclostrobin (FRAC group 11), the active ingredient in Cabrio and one of the active ingredients in Pristine and Merivon. The number of farms with strawberry anthracnose resistance to pyraclostrobin (group 11) is unknown but presumed to be widespread. Multiple studies have shown cross resistance between the group 11 fungicides. To avoid the further development of fungicide resistance to group 11, do not apply sequential applications of products in FRAC group 11 (Cabrio (11), Pristine (11+7), Merivon (11+7), Quadris Top (11+3), Luna Sensation (11+7)). Please see the Fungicide Resistance Action Committee (FRAC) guidelines for group 11 resistance management. If you suspect resistance to a group 11 product in your field, contact Erica Pate or Katie Goldenhar, OMAFRA (contact information below). Wherever possible, include a group M fungicide in your program for resistance management and to expand the spectrum of disease control. See Managing Resistance to Fungicides, Publication 360, Fruit Crop Protection Guide, Berries, for more information on managing resistance.
Integrated Management of Anthracnose Guidelines:
Anthracnose will be challenging to control in day-neutral strawberries with fungicides alone. Include other integrated anthracnose management practices.
- Apply chlorothalonil or captan before bloom for botrytis control.
- As much as possible apply broad spectrum fungicides (group M) during bloom.
- During harvest your options are more limited because of the longer REI and PHI intervals. Options include Switch, Diplomat, Quadris Top.
- Do not rely on group 11 products alone.
- Clean up diseased fruit and remove from field.
- Nitrogen management is very important. Avoid over-application of nitrogen. The source of nitrogen can also have an effect; avoid ammonium forms of nitrogen.
- Don’t let the plant canopy get too thick.
- Sanitize between fields (eg. equipment, tools, hands).
- Start new fields with clean plants from an accredited program. Plug plants from field-grown tips carry a higher risk.
- Work in older fields, and/or diseased fields last.
- Some new cultivars (eg. Keepsake) have tolerance or resistance to anthracnose – try these out on your farm.
For examples of fungicide programs and the list of products registered for anthracnose management see the attached pdf:
Erica Pate, Fruit Crop Specialist
Katie Goldenhar, Pathologist- Horticulture