At Risk Crops are popular crops with inherent disease challenges. The good news is effective control strategies can help ensure clean, healthy plants. This presentation from experts at Ball Horticultural Company covers Bsil.

1. At-Risk Crops: Basil
Nick Flax, Technical Services Specialist
Ball Seed Co. 622 Town Rd., West Chicago, IL
Email: nflax@ballhort.com Phone: 630-588-3193

2.  Downy mildew
 Peronospora spp.
 Aggressive pathogen, spreads
rapidly, hard to control.
 Systemic and will cause total plant
death if disease occurs.
 O. citriodorum and O. americanum
less susceptible.
 Disease occurs when
 Relative humidity is 85%+ in the
plant canopy.
 Chlorosis is characteristic symptom.
 Signs of sporulation = too late…
Basil (Ocimum basilicum & spp.) – Risk Factor

3. Environmental
• Lower %RH, HAF, VAF
• Periodical GH venting cycles
• Night-interruption lighting
Cultural
• Only use reputable seed source
• Select resistant varieties
• Avoid overhead watering
• Monitor crops judiciously
Chemical
• Preventative control is essential
• Rotate FRAC groups every app
• Good coverage critical for non-
systemic products
Basil Downy Mildew (BDM) – Managing Risk

4. Basil Downy Mildew (BDM) – Chemical Control
Trade Name Active Ingredient FRAC Group Max # Apps/Crop Notes
K-Phite, Fosphite, etc. phosphonate N/A
No less than 3d
between apps.
Do not apply during wet/high-
RH conditions
Ranman cyazofamid 21 9x Use a spreader-sticker
Heritage SC azoxystrobin 11 2x – 1 per stage 0-day PHI
Micora mandipropamid 40 2x – 1 per stage 1-day PHI; use spreader-sticker
Segovis oxathiapiprolin 49 [formerly U15] 2x Increase app. vol. w/canopy size
Subdue MAXX mefenoxam 4 2x – 1 per stage
Apply as tank-mix with full rate
of companion product
*Biological/biorational fungicides have shown some efficacy, but few studies have consistently demonstrated
sufficient levels of control for BDM.

5. At-Risk Crops: Basil
For more resources:
https://www.ballseed.com/QuickCulture/ProductionGuides/
Tech On Demand Podcasts:
https://www.growertalks.com/TechOnDemand/