If you grow grapes, you will most likely encounter disease this season. However, managing disease isn’t exactly easy. Sometimes, growers will experience a fungicide failure — a product just didn’t work. But understanding why it didn't work is the key to knowing what will work. Here are the top five reasons why your fungicide failed.
- The disease wasn’t accurately diagnosed — Accurately diagnosing the disease you are trying to avoid is the first step in ensuring you are using the best product for your vineyard. Whether Botrytis bunch rot or Powdery mildew, using a resource such as University of California IPM can help accurately identify the disease at hand.
- Incorrect calibration and application — Spraying with the correct size nozzle, pressure and speed is essential for consistent and complete coverage. You should always consult the product label on how much fungicide needs to be used and ensure the application equipment is in good working order prior to usage. If the application is off, you can guarantee unsatisfying results.
- Timing was too late — Most frequently, fungicides are more effective when applied preventatively. With diseases like Botrytis and Powdery mildew, for example, growers will discover the disease and may be too late to treat. However, growers who start earlier with fungicide applications may experience a short window of disease pressure, so that's where a curative fungicide application may be needed.
- Resistance — It’s possible your grapes have become resistant to the fungicide you’re using. However, alternating or combining effective fungicides with different modes of action (MOA) can help prevent pathogen populations from developing resistance to individual classes of fungicides. The mode of action that a grower uses can be the difference between a healthy vineyard and a disease outbreak with potentially disastrous consequences, so maintaining efficacy of materials is crucial. Incorporating unique modes of action is the first line of defense for growers looking to optimize their disease management programs, not to mention fend off fungicide resistance issues in their crops.
“Various modes of action will have different effects on the disease that you are after. If a mode of action is initially efficacious but, over time, experiences an adjustment in performance against particular fungi, it can become important to shift mode of action used to combat that fungi. This is a form of mitigation that can not only increase overall disease control performance, it can also help to alleviate those extraneous factors that developed in the fungi that limited the initial chemistry’s ability,” says Layne Wade, Technical Services Representative, UPL.
- The product wasn’t the right fit — The market is full of both old and new chemistries, and sometimes your fungicide option just wasn’t the best fit for your vineyard. It’s important to not adopt the mindset of "This is the product I’ve always used, so I'll go with it on my crops again this season.” UPL brings a portfolio of preventative and curative protection with ELEVATE®, PH-D® and PROCURE® so you can always find the right fit for your vineyard.
To control Botrytis fruit rot (Gray mold), ELEVATE® Fungicide (FRAC 17) gives grape growers high-quality protection. It features a unique active ingredient, fenhexamid, which has no effect on most beneficial insects and no known cross-resistance to other commonly used fungicides. With its one-day pre-harvest interval, ELEVATE can be used from bloom to within one day of harvest.
A broad-spectrum, Group 19 fungicide, PH-D provides excellent knockdown of Powdery mildew, Botrytis and other secondary rot-forming fungi such as Cladosporium. Its unique mode of action makes it a perfect addition to your resistance management tool box. PH-D features a 4-hour re-entry interval (REI) and a zero-day PHI, and can be applied preventatively in grapes when climatic conditions exist for the development of disease infection.
Rapidly absorbable and locally systemic, PROCURE works as both a protectant and curative that’s ideal for in-season relief of Powdery mildew. The fungicide has a unique mode of action and is tank-mixable, making it an ideal rotational partner with other fungicides, including PH-D® Fungicide, as part of your resistance management program. Its flexible application timing and a 1-day pre-harvest interval even allows for late-season application.
Although you should consider all five factors when planning your fungicide sprays,
a strong management plan is key to balancing expectations for your crops. Implementing all components together is what growers truly need for effective disease control in their vineyard.
At UPL, you can count on a complete line of grape protection products and a staff dedicated to keeping your vineyard running strong. Contact your retailer or UPL sales representative for additional information, or visit www.arysta-na.com.