Downy mildew

Contributor: Institut de Recerca i Tecnologia Agroalimentaries
Date Compiled: 2025
Creative Commons "Attribution-Share Alike"
Bremia lactucae (downy mildew of lettuce); Initial and later symptoms. Image copyright: ©Dr Philip Taylor (CABI)

Prevention

Solution Production stage (if possible with reference to BBCH scale)
Crop rotations
Pre-season
Using resistant varieties
Sowing/Planting
Use drip irrigation
Sowing/Planting

Monitoring

Solution
Observation: presence/absence
Favorable weather conditions

Control

Regulations surrounding biological products can change rapidly – always verify products recommended here with the most recent legislation and lists of products registered for your country
Solution Product Category Production stage (if possible with reference to BBCH scale) Max nb. of a. i. application/year Application Details and Notes (commercial product example) Chemical Group Risk resistance (FRAC Code)
Copper fungicides
Elemental fungicide
Start of treatments since there are favorable conditions for the development of infection. Suspend treatments 3 days before harvest
28 kg/ha in 7 years. It is recommended not to exceed the average quantity of 4 kg/ha of copper per year on the crop.
(BIOCUPRO) Dosage: 3,2-6,0 L/ha
Inorganic
Low risk (M01)
Sweet orange essential oil
Biological fungicide
6
(LIMOCIDE ® ) Dosage: 3L/ha
Natural compound
Bacillus subtilis (strain IAB/BS03)
Microbiological fungicide
BBCH 12 - 49
5
(FUNGISEI® ) Dosage: 1 - 3 l/Ha
Bacillus subtilis (strain IAB/BS03)
Microbiological fungicide
BBCH 14 - 46
5
(MILDORE® ) Dosage: 0,4 - 1,2 Kg/ha

Regulations surrounding chemical products can change rapidly – always verify chemicals recommended here with the most recent legislation and lists of products registered for your country
Solution Product Category Production stage (if possible with reference to BBCH scale) Max nb. of a. i. application/year Application Details and Notes (commercial product example) Chemical Group Risk resistance (FRAC Code)
Cymoxanil
Synthetic fungicide
When first symptoms occur. Suspend treatments 7 days before harvest
1 (per crop cycle)
(CYMBAL) Dosage: 250 g/ha
Cyanoacetamide- oxime
Low to medium risk (27)
Mandipropamid
Synthetic fungicide
Start of treatments since there are favorable conditions for the development of infection. Suspend treatments 7 days before harvest
4 (1 intervention per crop cycle)
(PERGADO SC®) Dosage: 0,6 L/ha
CAA-fungicides (Carboxylic acid amides)
Resistance known in Plasmopara viticola but not in Phytophthora infestans. Cross resistance between all members of the CAA group. Low to medium risk. (40)
Azoxystrobin
Synthetic fungicide
Start of treatments since there are favorable conditions for the development of infection. Suspend treatments 7 days before harvest
3 (Among Azoxystrobin and Tryfloxystrobin)
(ORTIVA® TOP SC) Dosage: 1 L/ha
QoI-fungicides (Quinone outside inhibitors)
High risk (11)
Propamocarb
Synthetic fungicide
Start of treatments since there are favorable conditions for the development of infection. Suspend treatments 7 days before harvest
2 (per crop cycle)
(PREVITER) Dosage: 1,5 L/ha
Carbamates
Low to medium risk (28)
Amisulbrom
Synthetic fungicide
Start of treatments since there are favorable conditions for the development of infection. Suspend treatments 7 days before harvest
3
(LEIMAY®) Dosage: 0,6 L/ha
QiI - fungicides (Quinone inside inhibitors)
Resistance risk unknown but assumed to be medium to high (mutations at target site known in model organisms) (21)
The information made available here has been obtained from or is based upon sources believed by CABI to be reliable but is not guaranteed as to accuracy or completeness. Anyone acting or relying on such information does so entirely at their own risk. The efficacy of the IPM methods included above will depend on local conditions and might not always be suitable everywhere within the specified country.