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Fruit and Vegetables |
Gavel 75DF, a new protectant fungicide labeled initially on potatoes, is now also labeled for use on tomatoes and cucurbits in North Carolina. Gavel contains zoxamide (8.3 percent) and mancozeb (66.7 percent). Zoxamide is a new active ingredient that specifically targets preventative control of late blight and downy mildew. Mancozeb, in addition to being active against late blight and downy mildew, extends Gavel's spectrum of activity to pathogens such as Alternaria and Septoria. Like mancozeb, Gavel has a 5-day preharvest interval (PHI). A full label for Gavel is available on the Internet at: http://www.dowagro.com.
We have evaluated Gavel in disease control trials in North Carolina on cucurbits, potatoes and tomatoes. Our experiences are summarized below.
Cucurbits (Holmes):
The primary advantage that Gavel offers for cucurbits is against downy mildew. In a single fungicide trial in 2001, Gavel performed equal to Bravo Ultrex against downy mildew on acorn squash. Remember that downy mildew is a disease that usually occurs in late-summer. Forecasts and current status of the disease in the eastern U.S. are available on the Internet at: http://www.ces.ncsu.edu/depts/pp/cucurbit/. Muskmelons, pumpkins and squash are the main cucurbit hosts for downy mildew in North Carolina. Downy mildew of cucumber is controlled with resistant cultivars. All modern pickling and slicing cucumber cultivars have sufficient resistance to control the disease, in most years, without fungicide applications. Also, downy mildew of watermelons is uncommon in North Carolina.
The Gavel label states that some cantaloupe varieties (i.e., Harvest Queen, Gold Star, Super Star, Sweet and Early and Saticoy) are sensitive to Gavel. It also states that Gavel should only be used for downy mildew control if used preventatively and when other Gavel-labeled diseases (e.g., Alternaria leaf spot and Cercospora leaf spot) are anticipated.
Potatoes (Cubeta):
In four years of testing, Gavel had comparable efficacy to Bravo Weatherstik and Dithane for managing late blight of potato (no tuber rot data) when applied on a preventative schedule. We have also evaluated Gavel rotated with two applications of Quadris with similar results. If growers are concerned about early blight, then the Quadris rotation would be a good choice.
Tomatoes (Shoemaker):
Gavel has received full registration on tomatoes to control early blight, late blight, Septoria leaf spot and other diseases. The zoxamide component provides improved control of late blight over mancozeb. In tests at Fletcher, North Carolina, Gavel has performed as well as chlorothalonil (Bravo and Equus) in preventing late blight on tomatoes and has been superior to straight mancozeb in preventing fruit infection. Tomato producers could substitute Gavel for either mancozeb or chlorothalonil products in their spray programs during late blight favorable periods. However, Gavel has a 5-day preharvest interval (PHI), the same as for mancozeb. Chlorothalonil products, with 0-day PHI, are preferred during harvest. For a complete update, go to the following site on the Internet and click on Foliar Fungicide Recommendations for Tomatoes in North Carolina: http://fletcher.ces.state.nc.us/staff/pshoemak.
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Last modified on May 24, 2002 by Stephen J. Toth, Jr.