Revus Top, a new cost-effective fungicide for grapes

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.

A new fungicide, Revus Top (Syngenta Crop Protection, Inc.), recently received a supplemental label for use in grapes. The supplemental label must be in the possession of the user at the time of fungicide application. This fungicide is sold as a “suspension concentrate” and has two active ingredients: mandipropamid and difenoconazole. Mandipropamid is a new chemical compound in the class of carboxylic acid amides (Fungicide Resistance Action Committtee [FRAC] group 40) with strong activity against downy mildew of grapes. It is also sold separately as the product Revus. The difenoconazole component belongs to the sterol inhibitor class (FRAC group 3) and has activity against powdery mildew, black rot and anthracnose. The pre-mix of two active ingredients ensures ease of use and broad-spectrum activity. However, Revus Top does not have very strong activity against Phomopsis; therefore this disease is not listed on the label.

Revus Top has preventative, systemic and curative properties. The systemic and curative properties are mostly due to fungistatic effects, which prevent sporulation. The application rate of Revus Top is 7 oz per acre, which translates to a cost of approximately $15 per acre. No more than two sequential applications should be made before alternating with another fungicide with a different mode of action. For powdery mildew control, Revus Top can be applied on a 10-21 day interval, and effective rotation partners are Pristine, Quintec, and Flint. For downy mildew control, a 10-14 day interval should be used. Examples of effective rotation partners are Ridomil Gold (MZ or Copper), Presidio, Gavel, Ranman, ProPhyt, Phostrol, and the EBDCs. For both powdery and downy mildew, use the shorter interval under high disease pressure. Thorough coverage is necessary to provide good disease control. A spreading/penetrating type adjuvant such as a non-ionic surfactant, crop oil concentrate, or blend is recommended at the manufacturer’s recommended rates. Do not apply more than 28 fl oz/acre (= four applications) of Revus Top per season. The restricted entry interval is 12 hours. The pre-harvest interval is 14 days.

Upon application, Revus Top rapidly bonds to the waxy layer of the leaf, providing rainfastness as soon as spray droplets have dried. Through translaminar movement within the leaf, Revus Top is able to provide disease control on both upper and lower leaf surfaces. In efficacy trials in New York and Virginia, Revus Top has had outstanding performance against powdery and downy mildew. In a small plot efficacy trial in cv. Concord in Fennville, Michigan in 2009, Revus Top provided excellent disease control (statistically similar to Pristine) as part of a spray program including Dithane and Ziram against black rot, powdery mildew and downy mildew (Table 1). (Downy mildew was more severe than normal in Concord in this location in 2009.) Revus Top is not as strong as Pristine against Phomopsis, although in this trial the difference was not statistically significant. Revus Top can be applied anytime during the growing season; however, for juice grapes, the best fit would be from bloom onwards, when multiple diseases need to be controlled.

Revus Top has a low risk to beneficial insects. However, it is toxic to aquatic organisms. This product has a potential for run-off into ground and surface water for several months or more after application. Poorly draining soils and soils with shallow water tables are more prone to produce such runoff. Runoff of this product will be reduced by avoiding applications when rainfall is forecasted to occur within 48 hours. Sound erosion control practices will reduce this products’ potential to reach surface water.

Table 1. Evaluation of disease control efficacy of Revus Top in Concord grapes in Fennville, Michigan, in September 2009.

 

 

Percent of leaf area or cluster area infected

Treatment, rate/A

Application timingz

Black rot on fruit

Powdery mildew on leaves

Downy mildew on leaves

Phomopsis on leaf petiole

Untreated

-

21.6x a

22.8 a

31.3 a

4.5 a

Dithane Rainshield 3 lb

1

Revus Top 4.17SC 7 fl oz

2, 3, 6

Ziram 3 lb

4,5

0.7 b

0.6 b

0.7 b

1.6 b

Dithane Rainshield 3 lb

1

Pristine 38 WG 8 oz

2, 3, 6

Ziram 3 lb

4, 5

0.4 b

0.3 b

0.4 b

0.9 b

z Spray dates: 1 = 10 June (immediate pre-bloom), 2 = 22 June (first post-bloom), 3 = 9 July (second post-bloom),
4 = 22 July (third post-bloom), 5 = 5 August (fourth post-bloom), 6 = 18 August (fifth post-bloom).
y
Column means followed by the same letter are not significantly different according to Fisher’s Protected LSD test (P≤0.05).

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