Fungicide update for blueberries

Here’s what you need to know this season to keep up with the changing world of fungicides for blueberries.

There are various trends in crop protection worldwide that are changing the landscape for fungicides. Several years ago, the threat of soybean rust, an invasive disease of soybeans, speeded up the review of sterol inhibitor (SI) fungicides by the EPA. While there are several new sterol inhibitors in the pipeline for blueberries, none have been labeled yet. A fungicide that is expected to become registered for blueberries later this year is Quash (metconazole), which in blueberry trials in Michigan had good to excellent activity against mummy berry and anthracnose fruit rot and will likely have activity against leaf rust. Another product in the pipeline is Proline (prothioconazole) which is also expected to have efficacy against mummy berry and leaf rust. The newer SI’s will likely have a shorter pre-harvest intervals than Indar and Orbit, facilitating their use later in the growing season, e.g., for leaf rust control.

Growers may also have noticed that some fungicides containing metals, like copper, have become more expensive – one of the reasons is the increasing price of copper and other mined metals worldwide. Furthermore, the availability of natural fungicide products, including biological control agents (e.g., Serenade) and plant extracts (e.g., Regalia, Sporan), has been steadily increasing. This has increased the number of disease control options for organic producers.

Generic fungicides are now becoming more common since the patents have run out on a number of older fungicides. In order to extend fungicide patents, some companies have also started developing pre-mixes of different fungicide active ingredients. Generic products by law have to have the same amount of active ingredient as the original fungicides. However, they may have different inert ingredients or different formulations.

Generic products may be more economical than brand name products, but most have not have been separately evaluated in Michigan and may not be specifically recommended in MSU Extension’s E-154 Fruit Management Guide. However, they are described in the “Fungicides and Bactericides for Fruit Crops” section. For more information on individual products, you can check out their labels and material safety data sheets on the following website: www.cdms.net. Generic products are expected to be similar in disease control efficacy to their brand name counterparts. However, there may be minor variations in efficacy, behavior or even potential phytotoxicity due to different formulations.

Read the fungicide label carefully as you would for any new product. Do not assume that labels of generic products are exactly the same as the brand name fungicides that you are used to. Sometimes there are differences in the crops that the product is labeled for or in the label instructions or restrictions. An example of this is Iprodione, which is labeled for blueberries, whereas the brand name product Rovral is not. The accompanying table lists generic products of common fungicides.

Brand name Product Active Ingredient Generic Products
Aliette fosetyl-Al Legion
Aliette phosphites (same breakdown product as fosetyl-Al) ProPhyt, Phostrol, Agri-Fos, Rampart, Fosphite, Fungi-Phite, Topaz
Bravo chlorothalonil Chlorothalonil, Chloronil, Echo, Equus
Orbit propiconazole Bumper, PropiMax, Propiconazole E-AG, Amtide Propiconazole
Ridomil metalaxyl MetaStar, Metalaxyl

 

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