Chlorothalonil is a contact and protectant fungicide that controls a broad range of fungal diseases. It is used on a number of crops. Due to the recent re-evaluation of chlorothalonil by the Pest Management Regulatory Agency (PMRA) there are changes that will affect how growers use the product, in relation to how it is mixed, loaded and applied. While some formulations have experienced changes to product use (Bravo®ZN), others have been discontinued altogether.
The re-evaluation has caused a discontinuation of Bravo 500 and Ridomil Gold SL/Bravo Twin-Pak formulations. The final day that these products will be available for purchase is May 10th, 2020, and the final day that growers will be able to make applications of these products is May 10, 2021. After this time, it will be the responsibility of the grower to properly dispose of any leftover product.
How will these changes affect how I use chlorothalonil products?
Changes to Number of Applications Permitted
There have been several use pattern changes made on Chlorothalonil labels, so it is important to check how your crop is affected. The full list of changes, including application rates and REIs can be found here. Please confer with up-to-date labels before use.
Changes to the number of applications permitted per season by crop:
Crop | 2019 | 2020 |
Blueberry (Highbush) | 3 | 2 |
Cabbage | 5 | 2 |
Celery, field | 9 | 2 |
Cherries (sweet and sour) | 4 | 3 (2 spring + 1 post-harvest) |
Cole Crops | 5 | 1 |
Cranberry | 3 | 1 |
Cucurbit Vegetables | 7 | 2 |
Onion, dry bulb | 3 | 2 |
Onion, green bunching | 5 | 2 |
Peach, nectarine | 4 | 3 (2 spring + 1 dormant) |
Potato, table | 12 | 3 |
Strawberry | 3 | 3 (2 spring + 1 dormant) |
Tomato (not for processing) | 9 | 2 |
Wheat | 3 | 2 |
Additional PPE, Buffer Zone Changes and REI
New requirements have been put in place to protect the applicator and persons who are handling the product, by increasing the amount of personal protective equipment (PPE) required. It is recommended to read the revised product label to obtain information on PPE and changes to the buffer zone requirements and restricted entry intervals (REI) for certain activities. Growers are reminded to have the updated label available to staff members who may come in contact with the product, as well as making them aware of the changes.
Implementation of Vegetative Filter Strips
Use of chlorothalonil requires a 10 meter (32’) vegetative filter strip (VFS) to be planted, if there is an aquatic ecosystem downhill from the field or sprayed area. A VFS is different than spray buffer zones: the filter strip is typically perennial, hardy, deep-rooted native vegetation that can slow runoff and filter out any pesticides that the runoff may contain.
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Introduction of Closed-system Transfer
The PMRA will now require growers, under certain circumstances, to use a closed-transfer and application system. The closed-system transfer specifically focuses on mixing and loading of the product. All potato applications, or any applications when more than 340 kg a.i. are handled in one day will be subject to these requirements. When product is directly transferred from the tote to the sprayer tank, this will now require dry poppet connections which comply with closed-transfer. Dry poppets are available from several manufactures and are also known by several names, such as dry poppet couplings or valves. Syngenta currently supplies a female dry poppet to male cam lever adapter with each tote of Bravo®ZN. Many chemical handling systems and sprayers are fitted with cam lever connections from the factory, in this case you can purchase a dry poppet to cam lever adapter. The existing dry poppet valves on the 450L totes of Bravo®ZN are already compliant with the closed-system transfer requirement and will not need to be altered.
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Additional Important Changes
Hand harvesting of processing tomatoes and application through irrigation systems on strawberries and cucurbits (cantaloupe, muskmelon, honeydew, squash, pumpkin, watermelon and cucumber) is now prohibited.
For further details on changes to Bravo products, please visit Syngenta.ca.