By the Chemtura AgroSolutions team of experts
The intensity of powdery mildew pressure is anybody’s guess this season, but vineyard owners and managers can be assured that they’ll deal with this disease at some point. The key is to stay ahead of powdery mildew, so be prepared to institute control measures soon.
That’s because season-long control is dependent upon reducing early-season inoculum and subsequent infection.
“Like any disease, the key is to prevent it. Don’t let it become established, otherwise you’re fighting it all season, and I really don’t want to do that,” says Chuck Ware, PCA with Wilbur-Ellis in Madera, California.
With hot and dry conditions, and early-season growth coming on strong, now is the time to be scouting and treating for powdery mildew. In fact, conditions recently triggered the University of California’s Powdery Mildew Index, indicating that conditions are right for outbreaks to occur. Current (relatively) cooler weather may slow disease progression, but there’s no doubt it’s waiting for an opportunity to ramp up.
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“I’m looking at beginning powdery mildew control programs in the coming days to get a jump on it,” says Ware. “Of course, variety susceptibility and farming practices used—some are more conducive to powdery mildew infection than others—play a role in when and where we see outbreaks.”
But regardless of those factors, it’s time to get a head start on control, he adds.
“Normally, I’d begin the season with a spray of copper and micronized sulfur, but given the current situation, I’m looking at a spray of micronized sulfur along with a systemic fungicide to address Phomopsis, in case we get a rain event in the near future,” explains Ware.
Then, as conditions warrant, Ware will begin his control option rotation featuring products like Viticure® fungicide, a systemic sterol inhibitor fungicide that’s labeled for protective and curative control for powdery mildew. It works by inhibiting development of cell walls in the target organism, which, without cell walls, cannot survive.
The product can be applied in rotation throughout the season, and is an excellent tool to help prevent fungicide-resistance issues. Viticure also suppresses Botrytis bunch rot.
Also be sure to visit with your PCA or Chemtura AgroSolutions™ representative for additional ways to ensure a successful spraying season:
• Mike Ansolabehere, Southern San Joaquin Valley: (661) 304-3023; email Mike.Ansolabehere@Chemtura.com
• Matt Loftus, Central San Joaquin Valley: (559) 960-1112; email Matthew.Loftus@Chemtura.com
• Carson Conover, North Central California: (530) 906-1504; email Carson.Conover@Chemtura.com
• Eric Leer, North Central California: (209) 531-6478; email
• Eduardo Garcia, California Coast: (805) 625-4101 or email Eduardo.Garcia@Chemtura.com