As the summer season approaches, May is a critical time to begin prevention measures for disease pressures. Taking control early in the season can help prevent the establishment of diseases such as Botrytis bunch rot or Powdery mildew.

High-humidity conditions, combined with elevated nitrogen levels and cluster compactness, can cause a Botrytis outbreak. Grapes in condensed clusters can crack due to pressure, creating ideal entry points for fungus as well as a moist habitat for the spores to germinate. Making matters worse, ripe berries can attract fruit flies, which help spread Botrytis on their bodies from plant to plant.

Powdery mildew also thrives in similar high-humidity and cool spring climates. The fungal infection settles on the surface of plant tissue and occupies the top layers of epidermis cells. Invasion of this disease can cause substantial damage to plant growth, crop yield and fruit quality.

Powdery mildew requires season-long maintenance because of early season inoculum and secondary infection caused by fungal spores that can infect, develop new spores and re-infect throughout summer months. Depending on weather, secondary infection cycles can occur approximately every five to 30 days.

Sulfur has proven to be particularly helpful in preventing powdery mildew, since it attacks disease-spreading spores and prevents them from germinating. However, many growers consider now a good time to transition from sulfur-based products to traditional fungicides. UPL brings an expanded portfolio of innovative solutions to keep your vineyard running strong, including ELEVATE®, MANZATE® PRO-STICK™, MICROTHIOL® DISPERSS, PH-D^® and PROCURE®.

ELEVATE Fungicide (FRAC group 17) provides locally systemic activity and is excellent at controlling Botrytis bunch rot and powdery mildew. ELEVATE can provide post-infection activity when applied early in the disease life cycle and has been shown to enhance the efficacy of other fungicides when used in a powdery mildew spray program. With a zero-day pre-harvest interval, you can use ELEVATE up to the day of harvest.

MANZATE PRO-STICK Fungicide (FRAC class M3) provides advanced formulation technology in the fight against key diseases such as dead arm and downy mildew. A market-leading, multi-site, protectant fungicide, MANZATE PRO-STICK has effectively been used for decades without a reported incidence of resistance, making it a standard in almost any disease management program.

MICROTHIOL DISPERSS Fungicide (FRAC group M2) combines sulfur and science to deliver excellent efficacy in a superior formulation for powdery mildew. MICROTHIOL DISPERSS also provides the added benefit of mite control. A patented micronized formulation process ensures a more consistent spray coverage and greater surface contact than other sulfur products. 

PH-D Fungicide (FRAC group 19) is a broad-spectrum fungicide that offers a high degree of powdery mildew and Botrytis control in grapes. Its benefit of a zero-day pre-harvest interval and 4-hour REI makes it an excellent option for disease management sprays close to harvest. PH-D is the only product in FRAC group 19, making it an important resistance management tool.    

PROCURE Fungicide (FRAC group 3) is rated as one of the highest for powdery mildew control. PROCURE has both protective and curative efficacies in controlling diseases, as well as systemic activity in the plant. When applied in a powdery mildew spray schedule, PROCURE will enhance the activity of registered fungicides used for Botrytis bunch rot control. It’s also available under brand name TRIONIC Fungicide in a larger pack size.   

For more information on how to tackle stubborn disease in your vineyard this season, contact your local UPL sales representative or visit www.upl-ltd.com/us.

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