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Crop and Pest Management Guidelines

A Cornell Cooperative Extension Publication
Page Contents
44007

5.2.8 BLOOM

Pest(s)

Materials

Rate per Acre

Comments

5.2.8 BLOOM (when 80-90% of the caps have fallen)

Botrytis bunch rot

Fungicidal protection at bloom and/or pre-bunch closure, can be important during seasons that are wet and may be critical in such years on tight-clustered varieties, particularly those with early closing bunches (e.g., Vignoles). Thus, growers who have had trouble controlling Botrytis when they have delayed applications until veraison (or later) should consider protecting against the disease at late bloom and/or pre-bunch closing (which can occur just 2-3 weeks after bloom on tight-clustered varieties)if the weather is wet during these times. Somewhat lower rates (e.g., the low end of labeled rate ranges) can often

be used at this time compared to what's necessary at veraison and pre-harvest IF good spray coverage is provided. Resistance Warning: All Botrytis fungicides are prone to resistance development after repeated use. Hence, it is important to follow the resistance management strategies detailed in the discussion on pesticide resistance management in Section 3.1 (e.g., maximum of two applications per year from any one Fungicide Group, never rely on one single Fungicide Group in any growing season).

Rovral Brand 4F

1.5-2.0 pt

Rovral and generic iprodione products (e.g., Meteor) should be tank-mixed with a surfactant or oil to improve absorption by the berries. Research shows that this improves control.

OR

Meteor 4F

1.5-2.0 pt

OR

Vangard WG

10 oz

OR

Scala 5SC

18 fl oz

OR

†Switch 62.5 WG

11-14 oz

OR

Inspire Super

16-20 fl oz

A rate of 20 fl oz/A of Inspire Super provides the same amount of cyprodinil, the active ingredient in Vangard, as 7 oz/A of that product. This is likely to be an adequate dose at bloom under most conditions, although research data are limited; under high disease pressure, it might be necessary to tank mix with an additional 3 oz/A of Vangard or another Botrytis-active fungicide to obtain best control. This rate of Inspire Super also provides the same dose of difenoconazole - the Revus Top component active against powdery mildew, black rot, and anthracnose - as 7 fl oz/A (the labeled rate) of that product.

OR

Elevate 50WDG

1 lb

OR

Flint Extra

3.8 fl oz

Resistance Warning: Research in VA has shown Botrytis resistance among the strobilurin (Group 11) materials to be common there; thus, it is also likely to occur in many NY and PA vineyards where these products have been used more than occasionally for a number of years, although this has not been investigated specifically. Nevertheless, based on our experiences with downy and powdery mildews, it is risky to rely on Flint Extra for control of Botrytis in vineyards with a significant history of strobilurin use, unless it is tank mixed with another product with good efficacy against this disease.

OR

Endura 70WG

8 oz

OR

*NY†Luna Experience

6.0-8.6 fl oz

*NY†Luna Experience contains the traditional DMI (Group 3) fungicide tebuconazole, which has no significant activity against Botrytis, plus a Group 7 material (fluopyram) similar to boscalid (the non-strobie component of Pristine), which provides activity against powdery mildew and Botrytis. The 6.0-fl oz rate is adequate for powdery mildew and for Botrytis during the bloom and post-bloom period, but the 8.6 fl oz/A is likely to be necessary for reliable black rot control unless another product active against this disease (e.g., mancozeb) is being used as well. It is recommended that the total number of applications of Group 7 materials (*NY†Luna Experience, Pristine, and Endura) be limited to no more than two per season.

OR

*NY†Luna Sensation

*NY†Luna Sensation is another newer product with the same fluopyram active ingredient as *NY†Luna Experience, but combined with trifloxystrobin, a

traditional strobilurin (Group 11) fungicide. Unlike *NY†Luna Experience, both active ingredients have good to excellent activity against Botrytis. The 7.0 fl oz label rate for Botrytis delivers a fluopyram dose about equal to 8.6 fl oz of *NY†Luna Experience and about the same amount of trifloxystrobin as 3.5 fl oz of Flint Extra for good to excellent Botrytis control. CAUTION: Do not apply this product to Concord grapes or injury may occur.

OR

Pristine

18.5-23 oz

At rates typically used against other diseases, Pristine provides some suppression of Botrytis but should not be depended upon for control under moderately high disease pressure, particularly later in the season. In several tests, Pristine has provided good control when applied during the late bloom period at the highest rate labeled against other diseases (12.5 oz/A), also specified for Botrytis "suppression" on the label, and has provided very good to excellent control at a rate of 19 oz/A.

OR

*NY†Intuity 4SC

6 fl oz

*NY†Intuity is a strobilurin fungicide for control of Botrytis and suppression of powdery mildew. In limited NY and PA trials, *NY†Intuity provided good to fair control of Botrytis equivalent to current standards like Elevate, Vangard, Scala, and †Switch. Do not use on V. labrusca, V. labrusca hybrids or other non-vinifera hybrids. Avoid mixing with organosilicone surfactants.

OR

Botector

6-8 oz

Botector is a preparation of a living yeast-like organism that competes with the Botrytis fungus for colonization sites on the grape flowers and berries. It provides protective activity only and can be killed by some broad-spectrum fungicides used for managing other diseases. ProBlad Verde is a fragment of a naturally occurring plant protein that has activity against some fungi. It has provided fair to good control in a limited number of NY trials with moderate disease pressure.

OR

ProBlad Verde

18.1-45.7 fl oz

OR

*NYMiravis Prime

10.3-13.4 fl oz

*NYMiravis Prime is a combination of a new succinate dehydrogenase inhibitor fungicide (SDHI, Group 7) and fludioxonil (Group 12), introduced about 25 years ago for Botrytis control. Fludioxonil is also found in another combination product called Switch for Botrytis control. Most, if not all of the activity against Botrytis comes from fludioxonil. The 10.3-13.4 fl oz rate of *NYMiravis Prime delivers the same amount of fludioxonil as the 11-14 oz label rate range of Switch.

OR

Howler

2.5-7.5 lbs

KEY FOR SECTION 5.2:

* Federal restricted-use pesticide*NY Restricted-use pesticide in New York State

† Not for use in Nassau/Suffolk Counties.^ Not registered for use in New York State at press time