Controlling powdery mildew is a process. Early-season treatment is a good start, but that doesn’t mean you can back down the rest of the year. Staying ahead of powdery mildew means applying the right materials at the right times for the vineyard.
Many tools help PCAs and growers determine what fungicides to use during different stages of the powdery mildew life cycle for best control, but Sonoma, Calif.-based premium wine-grape grower Mike Saini still sees people skimping on their sprays.
Follow label recommendations
“Vineyard owners can be tempted to cut costs by using less fungicide,” says Saini. “Cutting rates and stretching intervals seems to save money in the short term, but long term, you’ll have a higher concentration and incidence of powdery mildew overall.”
He urges grape growers to consider the bigger consequences of incomplete powdery mildew control. Two of the potential dangers are resistance development and decreased product efficacy.
“Even if the disease appears to be controlled with less fungicide, diminished control may not kill all the spores, allowing some to get inside the vine wood, damaging the vine and future production.”
Prevent breakouts every year
Even a single season of poor powdery mildew management means PCAs and growers will have to play catch up by applying higher fungicide rates at shorter intervals to get control, Saini cautions.
“Powdery mildew eradication costs more than prevention because you use higher rates of stronger materials more often,” he says. “Spending a little more this season on powdery mildew control saves you money in coming seasons.”
Learn from others
Mike Saini and Rod Yraceburu, a Kerman, Calif.,-based PCA and grape grower, share their strategies for successful powdery mildew control here. And Henry Wu, Technical Sales Support Representative, Chemtura AgroSolutions, advices how to be sure you are spraying efficiently here.