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Fungicide Spray Workbook for Virginia Wine Grape (2012)

April 2012

Workbook for Developing an Effective Fungicide Spray Program

for Wine Grapes in Virginia, 2012

Mizuho Nita, Ph. D. Research/Extension Grape Pathologist

Virginia Tech, Alson H. Smith, Jr. Agricultural Research and Extension Center

595 Laurel Grove Rd. Winchester, VA 22601

Phone: 540-869-2560 ext. 33

Email: [email protected] I have a blog where I discuss grape disease management issues almost daily during the season. Please visit here: http://grapepathology.blogspot.com/ Also, my webpage at Virginia Tech has been changed to: http://www.arec.vaes.vt.edu/alson-h-smith/grapes/pathology/index.html. The purpose of this workbook is to help wine grape growers in Virginia develop an effective fungicide spray program for their production. The targeted diseases are: powdery mildew (PM), downy mildew (DM), black rot (BR), Botrytis bunch rot, and Phomopsis cane and leaf spot (Ph). Any of these diseases can be a significant threat to yield if an outbreak occurs. The proposed spray schedules intend to provide a simultaneous control of these five major grape diseases, and include several options that you could use as guidelines for your program. The workbook does not include all fungicides registered in Virginia for control of these grape diseases; thus, two supplemental tables are attached for your reference. Table 3 shows the effectiveness of fungicide you may select, and Table 4 lists fungicides that are prone to the development of fungicide-resistant pathogen isolates. This information is merely suggested guidelines, and it is designed to serve as “food for thought”. There are many things to be considered beyond these guidelines, such as specific characteristics of your vineyards, varieties, training systems, diseases present in the field and their history, local weather patterns, your budget, etc. It is important to make sure that your program addresses these issues, and provides a good management of diseases while it fits your budget. Fungicide prices vary by year and location; thus, make sure to calculate cost per acre as you plan your program. The schedule I’m presenting here is based on commonly used fungicides such as mancozeb and sulfur products. It is simply because these products have lower risk of fungicide resistance development and generally cost less. However, I am not endorsing any particular products. This information is not a replacement of the existing spray guide (Pest Management Guide, or PMG) from Virginia Tech. Please think of this as a supplemental workbook that focuses on disease management. Intention of this workbook is to add a little more detail on the fungicide spray program to help you develop your own program. PMG for grape can be found at (http://pubs.ext.vt.edu/456/456-017/Section-3_Grapes-2.pdf) Finally, please read and follow the fungicide label. As you know, the label changes all the time. Although the effort has been made, because this guideline presents quite a bit of information, some may not be current. [If you find a typo or confusing point, please feel free to contact me.] The label should provide information on allowable usage rate, cautions and restrictions on use, and recommendations on fungicide resistance management strategies. [New for 2012. I am converting this guide into a workbook that fills the gap between the PMG and your fungicide template/record. It is still a work in progress; so, please send me any comments or suggestions!]


April 2012

Review of 2011 season As with last year’s version, I would like to start off with this guideline with a review of 2011 season. I will cover mainly about what happened in Winchester area and in our experimental vineyards. As you know, each location is unique, but I am hoping that this review will help you remember what happened in your vineyards so that it will help you plan this season’s planning. Bud break to bloom: Bud break of 2011 was about the average for us in Winchester. It was 14 April for Chardonnay and Cabernet sauvignon followed it 5 days after. From bud break to bloom at 28 May, we had 15 rain events that were considered infection period for one of common early season diseases: Phomopsis (pictured below), or downy mildew, or black rot. Since temperature during the rain events were relatively warm (in mid-60’s), some of you might have experienced more than usual Phomopsis or black rot.

As for downy mildew, we did not observe notable development of downy mildew despite of rain events before bloom. One of the reasons is that we observed only a few numbers of nights where temperature is above 55F and relative humidity was very high (>85%). Such condition promotes spore production of downy mildew. Also, I think overall level of inoculum was probably low in our area because 2010 was relatively dry, especially toward the end of the season. Bloom to veraison: up to the first week of July, we were receiving rain constantly. I counted six infection events for Phomopsis and Black rot, and eight for downy mildew. At the same time, periods in between rains were dry. This condition (plus abundant inoculum from 2010 season) promoted development of powdery mildew in our

vineyards. As with 2010 season, it started early (around bloom), and by the time the berries are BB size, I recorded more than 50% disease incidence in our control (minimum sprayed) vines.

Also around late June to early July, folks in central VA experienced a series of thunderstorms that came with hails. In addition, probably due to rain and cloud cover during that period, some of us observed development of Botrytis on clusters. Since this pathogen likes high sugar contents, it tends to appear when berries are maturing, but under humid conditions, it can infect younger berries. Then we experienced a dry mid-summer. There were rains here and there, but none of them were significant. In fact, it was so dry that birds started pecking on grapes in early part of August. I went to a conference for 10 days, and when I came back, all my berries are gone! Good thing was that I was not using them for my experiments this year. At that point, I thought maybe we would have another year like 2010. Well, I was wrong!

We experienced three days of rain from Irene in the end of August, and then Lee hit us. During the month of September, Winchester area


April 2012

received 6.5 inches of rain, and I counted only a few days without rain or cloud cover. Veraison to harvest: Unfortunately, rain did not stop there. We received continuous rain throughout the month of October, dropping 4.2 inches of rain in Winchester area. When berries are exposed to such a long and consistent wet conditions, pathogens won’t give them a break. What many of us experienced were downy mildew (on foliage or severe enough to cause defoliation), Botrytis bunch rot, sour rot, ripe rot, and sooty-mold like dark mold. Sour rot requires wounding event to cause disease, and Botrytis can take an advantage of wounds as well. That means that controlling birds and yellow jackets or hornets reduce the risk of Botrytis and sour rot development. Local bird population differs, but in general, bird netting and calling machine are two good tools for managing birds. As for yellow jackets, use of commercial trap during the early part of the season to prevent a queen to build a nest nearby vineyard can reduce the risk of emergence at latter part of the season. I have been hearing more about ripe rot since 2010 season. The pathogens (Colletotrichum acutatum and C. gloeosporioides) tend to prefer warm weather (as we had in 2010), but last year’s prolonged wetness made ripe rot appear again regardless of cooler weather. Although it does not cause significant rots in many cases, even a small amount of spores of ripe rot pathogens (3%) are known to affect wine quality. Based on a small experiment we conducted in 2011, we have confirmed that these pathogens can infect berries regardless of their developmental stage. (i.e., mature grape berries do NOT develop resistance against this pathogens.) The severe infection also cause

berries to shrivel or shrunk while the rachis of infected clusters tends to be clean (e.g., clusters on the left-side of the picture below). I found peduncles showing some discoloration, so, it seems that the pathogens infect berries then move toward green tissues.

Although captan is listed as one of effective compounds, a recent study showed that one of pathogens of ripe rot is insensitive to captan. Literatures show mancozeb and strobilurins are effective against ripe rot. Thus, if you cannot control ripe rot with captan, Pristine or other QoI (Aboud, Qadris Top, Sovran, etc) can be a good option. So, what we should expect for this season? Due to last year’s conditions (= environment conducive for powdery mildew during early then became very wet for downy mildew development), some of you probably face higher risks of these diseases than a typical year. If you are concerned, make sure to have some materials that work against these diseases. A simple combination of mancozeb and sulfur suffice to provide early season protection (plus mancozeb works against Phomopsis and black rot), then, switch to newer materials, such as DMIs, around pre-bloom spray. When you use newer materials, please remember to rotate mode of actions because they are prone to the development of resistance.


April 2012

List of new products on the horizon (2012)

LUNA Experience (Bayer). The a.i. is fluopyram (FRAC code 7 Pyramidas, medium risk), which has efficacy against PM and Botrytis. It has protective activity and it moves systemically (probably locally systemic). Note: the general REI for Luna Experience is 12 hours; however, for leaf pulling, tying, and training is 10 days. The PHI is 14 days. The product will be a pre-mixed product of fluopyram + other compound, and for grape, Luna Experience (fluopyram + tebuconazole) is the product. The release will be probably early 2012. It has been evaluated in 2010-11 at Winchester, and showed an excellent efficacy against powdery mildew and Botrytis Torino (Gowan). The a.i. is cyflufenamid (FRAC code U6 Amidoximes, no resistance risk information, but resistance isolates were reported), which is active against PM. It is not systemic, but shows a translaminar movement (vapor action) to improve coverage. The application rate will be 3.4 oz/A. I has been tested at Winchester in 2009-11 and provided good protection against PM. The expected registration is late 2012. Meteor (UPI). The a.i. is Iprodione (FRAC code 2, medium to high resistance risk) for Botrytis management (1-2 qt/A, REI 48h, PHI 7d). It is basically the same as Rovral. Botrytis is known to develop resistance to fungicide(s) relatively quickly compared with other pathogens. Please rotate mode of action!

Old news (fungicides introduced recently)

Inspire super. It is difenoconazole + cyprodinil (DMI + AP (Anilino-Pyrimidines), code 3 and 9, respectively: both are at medium risk for fungicide resistance development according to FRAC) pre-mixed material for PM control. The PHI is 14 days. It has preventative and curative characteristics, and is rainfast 2 hrs after application. The application rate is 14-20 oz/A. It has been evaluated in 2010 at Winchester, and showed good efficacy against powdery mildew. Forum (FRAC code 40). This dimethemorph product is specific for downy mildew. It is the same group as Revus (described below), thus, please be careful when you are thinking about rotation. Based on the results of Revus against downy mildew, it is expected to be a good protectant material. Rate is 6 oz/A, and the PHI is 28 days. Quadris Top. It is a difenoconazole + azoxystrobin (DMI + QoI, code 3 and 11) combination material for PM and Black Rot. The PHI is 14-day. The application rate is 8-15 oz/A. But note that PM in many Virginia vineyards has become resistant to azoxystrobin. Quash. It is a metconazole (DMI, group 3) product for PM. It has been used in stone fruit production against a variety of diseases. Switch 62.5WG. A cyprodinil + fludioxonil (AP + PP (PhenylPyrroles), code 9 and 12: both are low to medium risk) combination material for Botrytis and sour rot. It has been used for other crops such as strawberry, and it obtained a supplemental label for grape in Sept 2009. The application rate is 11-14 oz/A. One note on a fungicide with both cyprodinil and fludoxonil is a concern on its degradation. It has been shown that it tends to lose its efficacy quicker under sunny condition due to photo-degradation, plus cyprodinil has a tendency to evaporate. Thus, it may not be as effective as it should be under a hot sunny summer condition. Ranman (FRAC code 21). This is a relatively new downy mildew material (cyzafamid) from FMC. Based on studies done by Cornell and PSU, it has a good efficacy. This is a systemic material with curative activity. The rate is 2.1-2.75 fl oz/A and the PHI is 30 days.


April 2012

Reason (FRAC code 11). It is a relatively new downy mildew material (famoxadone) from Bayer; however, the mode of action of famoxadone is the same as that of strobilurins (QoIs, e.g. Abound). Since we have been observing resistant isolates against Azoxystrobin (Abound), it may not work for us. This material was tested at Winchester AREC in 2011 season; however due to lack of rain, we did not obtain data. Rate is 2.7 fl oz/A, and the PHI is 30 days. Revus (FRAC code 40). It is a downy-mildew specific protectant fungicide (mandipropamid). A field trial for Revus and Revus Top (Revus + difenoconazole: labeled April 2010, FRAC 40 + 3) has been conducted at Winchester in 2010-11, and results showed that products have very good protective activities. Plus the 14-day PHI makes it an attractive choice for late season downy mildew material. It is low to medium risk fungicide for chemical resistance; however, resistant DM isolates against the same group were found in Europe. Revus Top may be phytotoxic to Concord and Noiret grapes, thus, if you have an American variety, please use it with a caution. Tanos (famoxadone + cymoxanil) (FRAC code 11 and 27). It is a relatively new downy mildew fungicide (curative and protectant). The mode of action of famoxadone is the same as that of strobilurins, thus, the same precautions regarding chemical resistance will apply. Need to tank mix with another broad spectrum fungicide such as mancozeb. It has been tested at Winchester in 2009 by itself. Results indicted that it can reduce disease severity, but not able to provide adequate suppression of downy mildew. Since resistant isolate against QoI is known, the efficacy was probably provided by cymoxanil, which is known to have a short residual activity. Please follow the label and mix it with a partner fungicide. Vivando. The active ingredient (a.i.) is metrafenone (FRAC group U8 Benzophenone, no resistance risk information) which has efficacy against Powdery Mildew (PM). It has been shown to disrupt hyphae and spore formation of PM fungus. The product became registered in 2010. The rate is 10.3 fl oz/A, it has a protective activity of 14-21 days. The PHI is 14 days. It may be locally systemic. It has been evaluated in 2010-11 at Winchester, and showed good efficacy against powdery mildew. Zampro. The a.i. are ametoctradin + dimethomorph (FRAC code 45 and 40, low to medium risk) which has an efficacy against downy mildew (DM). It has been tested at Winchester location in 2010-11 with rates of 11oz and 14oz/A; however, due to the lack of DM development, we need to test it again in 2012. Note: It seems that there are products with a new mode of action, and at the same time many others are pre-mixes of existing mode of action. I do not know how the pricing will be, but newer materials tend to be more expensive. Making a decision on fungicide application schedule is always difficult, especially during the season, so please plan ahead. Some tips are: 1) understand the target organism; 2) know the disease history of your vineyard; 3) keep an eye on the weather conditions in your vineyard; 4) rotate the mode of action to reduce the risk of development of fungicide resistant isolate; and 5) be mindful about your budget! Note 2: Fenarimol (Rubigan® AS, Vintage® SC and Focus®, from Gowan) has been taken out from the market last year. It was due to their business decision. The distribution channel typically has 2 years from the official date of cancellation to sell existing inventory of fenarimol products. Growers typically have no time limitation to use up fenarimol products they have purchased. (Please remember to keep and follow the label!) It is sad to loose a good product that can be an alternative option for our powdery mildew. It belongs to group 3 in FREC code (DMI, or Sterol Inhibitors or SI), thus, the mode of action is the same as other SI's, such as tebuconazole, myclobutanil, etc.


April 2012

Notes on fungicide resistance Powdery mildew. As many of you are aware, populations of powdery mildew in many locations in VA have developed resistance to the strobilurin (QoI) fungicides (Abound, Sovran, and Flint, and the pyraclostrobin component of Pristine), and there is evidence of the development of partial resistance to the sterol-inhibiting (DMI) fungicides (Rally (Nova), Rubigan (Vintage), and Elite) (please refer to Table 4). All of these materials were very effective against powdery mildew pathogen when they were introduced, but with time, some populations became less sensitive to the material. These fungicide resistant populations tend to emerge (either by selection or mutation) after consecutive use of the same materials over several years. In VA, a resistant population against QoI fungicides was reported after 10 applications of the material over the life of the vineyard. However, the pathogen population is complex and difficult to predict. It requires extensive lab testing to find out whether you have those resistant populations or not in your vineyards. If you are in doubt, please contact either Dr. Anton Baudoin or me. If these materials have been used in your vineyard regularly for several years, you need to consider using alternative materials for powdery mildew control. Sulfur fungicide, JMS Stylet Oil, Quintec, Endura, Luna Experience, Vivando, or potassium salts should provide a good to fair control (Table 3E). Pristine is a combination of a strobilurin fungicide and Endura; thus, it should be effective. However, since you are applying a strobilurin, the fungal population in the vineyard may retain its resistance to the strobilurin fungicide. Sulfur fungicides are effective in powdery mildew control, and because of its nature, there are less (some say no) risk of fungicide resistance development. However, if you have sulfur sensitive varieties, it may not be the best option. Downy mildew. Populations of downy mildew pathogen that are resistant or less sensitive to the strobilurin fungicides (Abound, Sovran (Meteor), Flint, Pristine, Reason, and the famoxadone component of Tanos) are widespread in Virginia. The story is similar to that of powdery mildew. This group was very effective against downy mildew when introduced, but with time, some population became less sensitive to the material. As with powdery mildew, it requires extensive lab testing to find out whether you have those resistant populations or not in your vineyards. If the strobilurin fungicide has been used in your vineyard regularly for several years, then you need to consider using alternative materials for downy mildew control. Mancozeb, Captan, Ridomil Gold MZ, Ridomil Gold Copper, Revus, Presidio, a copper fungicide, and a phosphorous acid (phosphite) fungicide have good to fair efficacy against downy mildew pathogen (Table 3B). Pristine is a combination of a strobilurin fungicide and Endura, and since Endura is not effective against downy mildew, it is basically the same as other strobilurin fungicides. There have been cases where downy mildew pathogens became resistant or less sensitive to mefenoxam (a.i of Ridomil) in European vineyards and in other cropping systems; however, we have not seen the same trend in North American grape production, yet. It is probably due to the limited usage of mefenoxam in the grape production and it is probably better kept in that way. Please avoid over-usage of Ridomil products in your vineyard. The same principals about resistant management will apply to other newer materials, such as Revus or Zampro [Note: Zampro may or may not be available in 2012]. For both powdery and downy mildew cases, if your vineyard is new or you haven’t used these materials extensively in the past years, fungicide resistance in these pathogens may not yet be a problem. But overuse of these materials will result in a development of resistant population soon or later. To avoid fungicide resistance development, please avoid two sequential sprays of any material that is at risk for resistance development. Switching to a fungicide with a different mode of action (i.e., DRAC code or fungicide class) is the key (Table 4). [i.e., consider that all strobilurin fungicides have the same mode of action regardless of which company manufactures them; the same is true for sterol-inhibitors.]


April 2012

Most of these fungicides with a risk of fungicide resistance development have a limited number of applications per season listed on the label. Please read and follow the label. Examples of tactics to avoid or slow down resistance development include:

§ Do not rely solely on chemical control for your disease management. Cultural practice such as proper pruning, shoot management, and leaf removal can decrease risk of disease development and promote better coverage by fungicide.

− Also note that powdery mildew pathogen prefers shaded area over exposed area. § Apply fungicide correctly. Application rate, spray timing, calibration of sprayer, nozzle type, etc, all

can affect the efficacy of the fungicide. Read the label carefully and follow. In addition, do not apply more than the label allows you for a season.

§ Rotating among fungicides from different classes (i.e., different mode of action). Avoid 2 consecutive applications of a resistance-prone fungicide (or fungicides from the same class) by alternating fungicide class.

− Please be aware that many of newer materials are a mixture of two or more materials, which may or may not be the same as one of rotation partner fungicides

§ Tank-mix newer (~single mode of action) fungicide with older (~multiple modes of action) fungicide (e.g., Vivando + sulfur)

§ Avoid repeated use of a high-risk fungicide. The greater the number of applications of the same fungicide class, the higher the risk of development of fungicide resistance to the class will be. Fungicides at low risk of resistance development include sulfur, copper, Bordeaux mixture, phosphorous acid products, mancozeb, captan, ferbam, ziram, stylet oil, potassium salts, and hydrogen dioxide (Oxidate).


April 2012

Table 1. Pesticide inventory: Let’s start your pesticide schedule planning with inventory check. Follow the example in the first row. Pesticide Type

Trade name FRAC or IRAC code

Rate /A

Amount needed per spray

Number of spray planned

Amount needed this year

Amount in the container

Need to purchase?

Fungicide Rally 40W 3 5 oz 15 oz 2 30 oz 10 oz Yes


April 2012

Table 2. A template for your fungicide application program The top part is an example of fungicides to be used. I used mancozeb and sulfur as a backbone of the program, and used a DMI, Quintec, Phosphorous acid (Phos in the table), Vangard, and Elevate as needed. You may use other products (I am not endorsing any particular products!). The timing of Ridomil application depends on the rainfall. If we receive many rains between bloom to 4-5 weeks after bloom, and downy mildew development is the issue, I prefer to use Ridomil (or Phosphorous acid products) to deal with infected tissues, but if it is dry, I will stick with mancozeb. Currently, we do not have many options for late season rots, other than captan for general fungal infection and Elevate or Vangard for Botrytis. Captan, Potassium salts and Oxidate may suppress some rot pathogens. Proper early disease management, especially PM and Botrytis management should lower the risk during late season. If you need an Excel version of this template, please visit my blog where you should find a link to a spreadsheet.

Spray # 0 1 2 2.5* 3* 4* 5* 6 7 8 9 10 11 12 13

Growth Stage Bud break 3" 10" 12" Prebloom BloomFruit set (1st

cover)BB-

Pea(2nd) Pea (3rd) Berry touch Veraison Preharvest Preharvest PostharvestWeek Week 0 Week 1 Week 2 Week3 Week 4 Week 5 Week 6 Week 8 Week 10 Week 12 Week 14 Week 16 Week 18 Week 20 Week 22

Dates in 2011 4/14/11 4/20/11 4/30/11 5/10/11 5/15/11 5/26/11 5/31/11 6/15/11 7/13/11 8/10/11 8/25/11Disease --> PhomopsisBasic material --> Mancozeb Mancozeb Mancozeb Mancozeb Mancozeb

Powdery Mildew

Sulfur Sulfur Sulfur +DMISulfur + Quintec

(or Vivando) sulfur +DMI

Sulfur (+Quintec

or Vivando) Sulfur Sulfur Sulfur Sulfur SulfurPotassium

salt SulfurDowny Mildew

Mancozeb Mancozebmancozeb or Ridomil MZ

Mancozeb or Ridomil MZ Mancozeb Phos Phos Phos Phos Phos Phos Phos

Black Rot

MancozebMancozeb

+DMI mancozebMancozeb +

DMI Mancozeb MancozebBotrytis BotrytisVangard Elevate Vangard

Watch out for 66-d PHI for

mancozeb!Insects Climbing

cutwormYellow jackets Nesting?

Grape Berry Moth Japanese beetle

Yellow jacket

Spray # 0 1 2 2.5 3 4 5 6 7 8 9 10 11 12 13Growth Stage Bud Break 3" 10" 12" Prebloom Bloom BB (1st cover) Pea (2nd) Pea (3rd) Berry touch Veraison Preharvest Preharvest Postharvest

Week? Weeek 0 Week 1 Week 2 Week3 Week 4 Week 5 Week 6 Week 8 Week 10 Week 12 Week 14 Week 16 Week 18 Week 20 Week 22Date in 2012

Your treatment Phomopsis Phomopsis Ph Phomopsis Phomopsis

Powdery Mildew PM PM PM PM PM PM PM PM PM PM PM PM PM

Downy Mildew DM DM DM DM DM DM DM DM DM DM DM DM

Black Rot BR Black Rot Black Rot Black Rot Black Rot

Botrytis Botrytis Botrytis

Critical Period for Clusters



Note: The fungicide listed above are examples. Week numbers are estimates.

Spray #3-#8 need to be flexible. Spray schedule will depend on the growth stage and rainfall. You may need to combine two into one spray or need an additional spray (e.g. spray #2.5). Around bloom, Ridomil would be a good choice when there are

#6 - depends on the level of PM. #7 - You may need to repeat based on the growth, e.g., #7 was repeated in 2010

Bird netting maybe needed. Last 3 applications will depends on the level of disease and weather


April 2012

SPRAY GUIDELINES FOR BEARING VINEYARDS

Pruning time disease consideration

There are several diseases that can cause infection on woody tissues, such as trunk and cordon. Some of examples are: Botryosphaeria canker, Petri disease (aka Esca), Crown Gall, and Eutypa dieback. In addition, some of other pathogens such as Phomopsis and Ripe rot (Colletotrichum species) are also capable of infecting woody tissues. These diseases typically cause damages to the infected vines in a long timespan. The infection today may not cause any obvious damage until a few years from now. Moreover, these pathogens act more like a “silent killer” and can shorten the life of the vine by 5-10 years. Thus, the prevention of these diseases will benefit you in a long run.

The most common wood-canker disease in VA is Botryosphaeria canker or Bot canker. The pathogen of this disease resides in old woody tissues, and spores will travel with rainwater to open wound (e.g. pruning wound) to cause infection. Several cultural approaches can significantly reduce the risk of infection. If you can afford, it is safer to practice double pruning and/or prune during late spring. Also, there is a chemical option (Topsin-M) available for VA. I wrote a 2-page handout for pruning workshops and posted on my blog, so, please take a look at it to learn more about the importance of the disease and management tactics.

The other disease to think about during later fall to winter is black rot. If you keep infected clusters on the trellis, it will produce spores that can be either airborne or splash dispersed. Moreover, these clusters can produce spores throughout the season. Thus, as you can imagine, it will be a very efficient source for next generation of black rot in the season. During fall and winter, it is probably very difficult to determine whether old clusters are infected by black rot or not; hence, it is probably better to take all of them out from your vineyard. (Note: Since the spores can be airborne, dropping on the floor probably won’t help much). Dormant and bud break disease consideration

There are a few diseases you want to pay attention to just prior to the season. The first one is Phomopsis cane and leaf spot. The pathogen (fungus, Phomopsis viticola) can infect healthy tissues under relatively lower temperature range (in 40’s), it resides in previously infected canes, cordons, and trunks, and its spores are disseminated by rain splash. Thus, spring rain events are good opportunities for this pathogen to cause infection. As soon as new tissues emerge after bud break, they are susceptible to Phomopsis infection. In addition, if you take a close look at them, you will notice that all the cluster parts are already present.

Unfortunately, we do not have any curative materials for this disease; thus, protection of new growth is the only mean of control. Mancozeb product (Penncozeb, Gavel, etc), and captan will provide a good control. You can pick either one of them. Typical rate is 3 lb/A, but it also depends on your sprayer, etc. Please make sure to set your sprayer to target new shoots, and if you can, turn off the unnecessary nozzles.

A dormant season application of lime sulfur at 10 gal/A is one of options for Phomopsis management; however, the efficacy is low to moderate, the material is corrosive and expensive, and it does not allow you to skip any of in-season protectant fungicide applications; therefore, I typically do not recommend it. The only exceptions are when you had a very severe outbreak of Phomopsis and/or anthracnose in recent years. Although captan and Pristine can be used in-season, a dormant season application of lime sulfur is probably the most effective application for anthracnose.

One of the commonly asked questions about the dormant application is a use of a copper material. When we tested fixed copper at 10 gal/A rate, it did not suppress Phomopsis; furthermore, I have not seen any compelling results against the other pathogens. A previous study showed suppression of powdery mildew with 20 gal/A rate of lime sulfur; however, since powdery mildew can multiply very quickly over a short time period, thus, it is probably not an effective tool. The other FAQ is the need for powdery mildew management at this time of the season. The answer to it really depends on the weather condition, recent history of powdery mildew, variety, etc. If you have compelling reason to believe you have high risk of powdery mildew, you can add low rate (2-3 lb/A) of a sulfur material. It will be relatively inexpensive insurance against unexpectedly early season powdery mildew outbreak.


April 2012

Growth stage or timing

Material and rate/acre

Comments

Dormant

Lime sulfur @ 10 lb/A If you had a severe Phomopsis and/or anthracnose problem in the previous year, this dormant season application may be an option to obtain a better overall control. However, it does NOT allow you to skip any of in-season sprays.

½- to 1-inch shoot

Note: Pictures presented here are

just a guide. It may or may not represent the

reality of your vineyard. Use your

judgment for application timing.

Mancozeb (Dithane DF, Penncozeb 75DF) @ 3-4 lb/A (for BR, Ph, DM)

PLUS one of the following for PM:

Wettable sulfur @ 3-4 lb/A or

Liquid sulfur (Super Six) @ 3–4 qt/A or

JMS Stylet Oil @ 1% concentration or

One of these PM materials Trade name Rate per A Elite 45WP 4 oz

Endura 4.5 oz Inspire Super 14-20 fl oz

Luna Experience 6-8.6 fl oz Mettle 3-5 fl oz

Quadris Top 8-5 oz Quintec 4 lf oz

Rally 40W 5 oz Rubigan (Vintage)

3 fl oz

Vivando 10.5 fl oz Potassium salts See comments

---- About PM materials ---

At this time of the season, you probably want to stick with economical options

such as sulfur and oil. Keep the newer materials for the critical time (bloom to

4-5 wks after bloom)

------ Alternative to Mancozeb ------

Captan 50W (2-4 lb/A) for DM and Phomopsis, Revus or Revus Top for DM (Revus Top has a label for Phomopsis too)

PLUS one of the following for BR:

a sterol-inhibiting (SI) fungicide [Elite 45 WP @ 4 oz/A

or Rally 40W @ 5 oz/A]

PLUS one of PM materials

Mancozeb is for protection against early Phomopsis (Ph), black rot (BR), and downy mildew (DM) infection. From this stage to 3-5 inch is the critical time for Ph infection on rachis and berries.

Choose one of the materials listed to protect against powdery mildew (PM) infections. Once PM infects on the rachis, it will give rise to later infections on clusters. Thus, unless you do not have PM problem, protection at this time of the year is still important.

Mancozeb plus sulfur is an inexpensive, effective option.

Sulfur and stylet oil are inexpensive but require thorough coverage to be effective.

Potassium salts, such as Nutrol (monopotassium phosphate), Kaligreen and Armicarb 100 (potassium bicarbonate), provide good control when applied to developing powdery mildew colonies. They do NOT provide protectant activity. Nutrol is cheaper than Armicarb or Kaligreen but comparable in effectiveness, according to research in New York. Consult the labels for usage rates and other recommendations.

Captan is less toxic to predator mites than mancozeb but also less effective against BR. If you are using captan and an SI, choose Rally or Elite rather than Rubigan.

To avoid vine injury:

§ Do not use sulfur on Concords, red-fruited French-American hybrids, or any sulfur-sensitive variety. Use stylet oil, an SI, Quintec, Endura, Vivando, etc.

§ Do not combine sulfur with oil or spray them within 14 days of one another.

§ Do not apply sulfur when the temperature exceeds 85°F.

§ Do not combine Captan with oil


April 2012

Pre-bloom early season consideration

Once shoots start to grow, it is never too early to think about black rot, downy mildew, and powdery mildew. These diseases show up around bloom in typical years; however, it also means that they start their activities at least a few weeks prior to it. I am not advocating spraying more materials; however, it is better and easier to prevent diseases early than try to catch up after an outbreak. Under favorable conditions, both downy mildew and powdery mildew can multiply very rapidly. Try to assess your potential risk by examining last year’s conditions, current season’s weather, as well as site condition, variety, training methods, etc. For example, an outbreak in the previous year most likely results in more number of spores available this season. If you had a significant amount of downy mildew last year, and this season started off with warm rain events, then you need to think about downy mildew.

Since many of plant diseases requires a certain length of wetness to complete its infection process, as well as site (e.g., air circulation, sun exposure), variety (e.g., Chardonnay is more susceptible), training system, and canopy management (more air circulation is better for disease management), will play an important role. If possible, invest into a weather station (preferably the one with wireless communication so that you do not need to visit it every day). [Note: I have an on-going project where we use the national weather service’s data to create maps with grape disease risk. Please stay tuned on this topic!]

A simple combination of mancozeb and sulfur suffice to provide early season protection. Both of them are relatively inexpensive material, and mancozeb works against Phomopsis and black rot. You can switch to newer materials, such as DMIs, around pre-bloom spray. However, I understand that some people prefer to use newer materials (DMI, quinoxyfen, etc) due to various reasons. When you use newer materials, please keep in your mind that you need to rotate of mode of action and also remember there is a limit to the number of application per product (= mode of action) per year because these newer materials are prone to the development of resistance. Please refer to page 5 for more information about resistance management.


April 2012



Comments

3- to 5-inch shoot or 7–10 days after the last spray

Same as ½- to 1-inch shoot spray

------ Note ------

When you wonder which fungicide to use, think about what was the primary problem in your vineyard, and also what is going on in this season. For example, if you had BR problems last year, and a weather forecast shows a warm rain event, you want to incorporate a fungicide against BR (such as Elite or Rally).

Some of you start your program at this stage. Just remember that from 1-inch to 5-inch may take only a few days!

Most fungicides act only as protectants. Thus, in order to protect new growth from fungal infection, these materials need to be applied before the rain.

7-day interval application needs to be considered if:

§ You are applying sulfur for PM (which does not require rain to infect tissue),

§ PM has been a concern in your vineyard

§ There has been a lot of rain (>1-2inches) since the last spray, or

§ It is unusually warm, and shoots are growing rapidly.

If rain is predicted between 7 and 10 days after your last spray, make another application before the rain.

6- to 10-inch shoot or 7–10 days after the last spray

Same as ½- to 1-inch shoot spray Please see above.

To lower risk of fungicide resistance development, rotate the mode of action. In general, 2-3 sprays of a resistance-prone fungicide (3 for SI and 2 for strobilurin) per season are the maximum recommended. Please plan ahead. Refer to Table 4 for the mode of action and risk of resistance development. Read and follow the label.

12- to 17-inch shoot or 7–10 days after the last spray (if necessary)

Same as ½- to 1-inch shoot spray

-----------

Remember to increase spray volume as the canopy fills out to ensure

thorough coverage!

-----------

Growth of grape depends on many factors. Please watch carefully and make a decision.

If your vines are approaching bloom, go to the pre-bloom spray guidelines. Otherwise, you may need to make one more spray using these materials.

Note on Stylet oil: oil can slow growth and retard fruit ripening later in the season. After this application, other fungicides would be the better choice.

Do not apply sulfur in very hot weather (above 85° F).

Do not combine Captan with oil


April 2012

Pre-bloom – bloom – first three cover spray consideration

This period between bloom to 4-5 weeks after bloom is the most important during the growing season because powdery mildew, downy mildew, and black rot can infect berries during this period. After 4-5 weeks, berries develop an ontogenic (~adult) resistance, thus, the risk of berry infection reduces dramatically. The length of time from bloom to the onset of the resistance varies among varieties. For American grapes, it is about 3-4 weeks, and for French varieties, it is about 5-7 weeks. Hybrids were probably somewhere between American and French varieties. During this critical period, it is better to be proactive about protection of your berries. This is the time you may want to think about use of newer materials that have either locally systemic nature or curative activity. [Note: people often talk about “Eradicant”, but there is no such thing, at least among our fungicides.] What we have at best is a curative material, which can stop the infection process, but it has little or no effect on established populations. So which materials are curative? It also depends on the target disease. For black rot, the DMI (SI) materials are known to provide curative activity. A previous study using Mycrobutanyl (Rally) showed an excellent curative activity up to 5-7 days after infection event. As for other DMIs, I am assuming they will have a similar activity, but there are no data to support this theory. For downy mildew, we have Mefenoxam (i.e, Ridomil) products and Phosphorous acid (aka Phosponate) products. Both will provide curative activity up to 5-7 days after infection event, plus it provide protective activity for 7-10 days. For powdery mildew, any materials have some level of curative activity because the fungi cause superficial infection, and majority of fungal body is exposed. However, once powdery mildew forms spores, the use of newer materials will have a higher risk of development of resistance. Another disease to be considered at bloom is Botrytis. This fungus can infect flower parts and reside in fruit until suitable it meets environmental condition (= wounding event), or resides in infected flower debris (cap etc.) within a cluster and serve as a source of inoculum later in the season. Thus, it is recommended to use one of Botrytis materials at the time of bloom. [Note: since both Pristine and Luna Experience have a good efficacy against Botrytis, powdery mildew, and black rot, you may think of using them. If you decided to do so, please keep in your mind that the REI for cane work of Pristine is 5 days, and that of Luna Experience is 10 days.] During this period, scouting for diseases (and insects, of course) is very important. Please spend some time on foot in your vineyards to look for diseases. It will help you evaluate your spray program and/or spray techniques. E.g., if you find development of powdery mildew regardless of your preventative schedule, there are several potential causes for that. It may be due to lack of coverage due to sprayer (e.g., pressure, nozzle, calibration, etc.) or amount of water used, or due to frequent rain that washed off the material, or lack of canopy management to promote airflow and reduce overlapping leaves, or simply you might have forgotten to add a material for powdery mildew!


April 2012



Comments

Pre-bloom to early bloom or 7-10 days after the last spray

Note: this is the critical time for grape clusters.

If you experience many rain events, both downy and black rot risk will be high. In such cases, you may want to consider using Ridomil (2.5 lb/A for Gold/MZ) or Phosphorous acid (see label for rate) products or Presidio (3-4 fl oz/A, need to mix with mancozeb or captan) that have a kick-back (curative) activity against DM, and Rally 40W against BR.

For more information about infection conditions for these pathogens, please refer to “2011 guideline for non-bearing vines”.

A. Mancozeb (Dithane DF, Penncozeb 75DF) @ 3-4 lb/A (for BR, Ph, DM)

PLUS one of the following for PM:


Liquid sulfur (Super Six) @ 3–4 qt/A or

One of these materials Trade name Rate per A Elite 45WP 4 oz





3 fl oz


------ Alternative to Mancozeb ------

B. Captan 50W (2-4 lb/A) (for Ph and DM), Revus or Revus Top (7 fl oz/A) for DM

PLUS one of the following for BR:

a sterol-inhibiting (SI) fungicide [Elite 45 WP @ 4 oz/A

or Rally 40W @ 5 oz/A]

PLUS one of PM materials

OR

C. Pristine @ 10.5 oz/A used alone

For early Botrytis control

Add one of the following to Options A and B

Trade name Rate per A Elevate 0.5-1 lb

Rovral (Meteor) 2 pt Scala 18 fl oz Switch 11-14 oz

Vangard 10 oz

OR

Use Endura at 8 oz/A as part of Option A or B for BR, Ph, DM, and PM or use

Pristine @ 12.5-23 oz/A alone as Option C (please see the note on page 21

about Pristine at higher rates.)

Pre-bloom to 2-4 weeks after bloom is the most critical period to provide protection of vines and fruits from BR, Ph, DM, and PM. After 4 weeks, the fruit becomes less susceptible to some of pathogens.

Early Botrytis control is also important to protect flowers from infection.

For BR, Ph, DM, and PM:

§ Options A and B: An SI will provide a somewhat better control against PM, and some post-infection activity against BR. But remember about fungicide resistance risk!

§ Option C: Pristine is a combination of a strobilurin and Endura. If strobilurin resistance of DM is present, Pristine should not be used alone. Captan, mancozeb, or phosphorous acid products can be tank mixed for DM control. Do not use Pristine (and Revus Top) on Concord or Noiret grapes

For Botrytis:

§ Elevate, Scala, Switch, and Vangard are effective only against Botrytis. Tank mix with your options for other disease, such as options A and B.

§ Pristine at the higher rate will control Botrytis as well as PM, BR, Ph, and DM. But, once again, there is the risk of fungicide resistance development.

§ Endura at the higher rate will control Botrytis as well as PM. You can tank-mix with mancozeb for protection against BR, Ph, and DM.

At bloom, scout for primary PM infections on rachises. (It can appear prior to leaf symptom development!) If you see actively sporulating colonies, potassium salt (Nutrol, Armicarb 100, or Kaligreen) can be an option. These materials provide moderate to good control of developing powdery mildew colonies but no protection against future infections. Thorough coverage is necessary.

To lower risk of fungicide resistance development, rotate the mode of action. In general, 2-3 sprays of a resistance prone-fungicide (3 for SI and 2 for strobilurin) per season is the maximum allowed. Please plan ahead. Refer to Table 4 for the mode of action, and read and follow the label.


April 2012



Comments

First post-bloom or 7-10 days after the last spray

Note: this is the critical time for grape clusters.

Adjust your spray schedule based on weather.

For BR, Ph, DM, and PM control

Same options as pre-bloom

For Botrytis control


------ Note -----

Use shorter spray intervals if you have sulfur in your program

Do not apply sulfur when temperatures are above 85° F.

Scouting for diseases is very important. Please spend some time walking through the vineyard to estimate disease development

It is still critical period for protecting fruit from BR, Ph, DM, and PM.

You need to keep an eye on weather. If the weather is warm and wet during bloom, use a shorter spray interval (7-10 days).

Scout for PM and DM

− Important: If you see many actively sporulating PM colonies (white mass on the leaves or fruits), avoid application of an SI, Quintec, Endura, or a strobilurin fungicide (Pristine, Abound, Flint, Sovran). It can promote the development of resistance. Instead, apply a potassium salt (Nutrol, Armicarb 100, or Kaligreen) or sulfur, or Stylet-oil to control infections. To ensure thorough coverage of foliage and clusters, use high volume.

− If you fail to protect fruit against PM at this point, it can result in the development of “diffuse infections” on fruit. This type of infection may be difficult see, but it will increase the risk of various fruit rots later in the season.

− Remember to rotate the mode of action.

− For DM, Ridomil Gold MZ (66-day PHI) or Ridomil Gold Copper (44-day PHI) can be applied, but watch out for their PHI. Revus and Presidio are new fungicides against DM with 12-day PHI. Some of these fungicides works against DM only, tank mix with other fungicide against BR, Ph, PM, and Botrytis.

Second post-bloom spray, no later than 10 days after the last spray

For BR, Ph, DM, and PM control


------- Note --------

Be aware of the seasonal limit on the amount of mancozeb you can apply (about 6 sprays at the 4 lb/ac rate, but read the label for your formulation) as well as the 66-day PHI. Captan plus Rally or Elite is a good alternative.

Use shorter spray intervals for sulfur and do not apply it when temperatures are above 85° F.

During this period (3 to 4 weeks after bloom) is near the end of critical period. The risks of DM and PM should be decreasing, but you still need to protect your vines until the fruit become more resistant.

If you have issues with ripe rot in the past, keep your vines protected with either mancozeb or a QoI material.

Watch the weather and continue scouting for PM and DM

To lower risk of fungicide resistance development, rotate the mode of action.

Observe the seasonal limits on total applications of resistance-prone fungicides.


April 2012



Comments

Third post-bloom spray or 10–14 days after the last spray

Note: The general guideline for the late season summer spray is 10-14 day interval. Please adjust it based on the history of diseases in your vineyard and recent weather conditions.

A phosphorous acid product (Phostrol, ProPhyt, or Agri-Fos) at the labeled rate and/or captan (Captan 50WP) @ 3–4 lb/A

PLUS one of the following:


Liquid sulfur (Super Six) @ 3 qt/A or

One of these materials Trade name Rate per A Elite 45WP 4 oz





3 fl oz


For late Botrytis control

Use one of followings: Trade name Rate per A

Elevate 0.5-1 lb Rovral (Meteor) 2 pt

Scala 18 fl oz Switch 11-14 oz

Vangard 10 oz

OR

Use Endura at 8 oz/A as part of PM program or use Pristine @ 12.5-23 oz/A alone (please see the note on page 21 about Pristine at higher rates.)

------ Note ------

Choose a phosphorous acid product that is registered as a fungicide, such as those listed here, not a nutritional supplement or “plant conditioner.” Please consult the label for the appropriate rate.

§ Do not use Flint on Concord grapes.

§ Do not combine Captan or Sulfur with any form of oil.

At this point (more than 4 weeks after bloom), the risk of DM and PM berry infection should be over. BR risk is also low, but some variety may still be susceptible for 1-2 more weeks.

This is another critical period for Botrytis management. Especially with tight cluster varieties, it is ideal to deliver fungicide chemical into the inside of clusters before bunch closure.

A phosphorous acid product works against DM, and DM alone. If the weather has been unusually wet and/or you have problems with BR or Ph, then captan will be a better choice. It offers not only protection against Ph and BR, but also provide good control of DM and other late season rots. Otherwise, phosphorous acid products are inexpensive and effective for DM control.

If weather is dry, DM control may not be needed. However, PM can infect even if weather is dry, and rachis tissues are still susceptible at this time of the season. Many vinifera varieties and some hybrids may need PM control throughout the season because PM can hinder photosynthesis by covering leaf areas, and also there is a chance of rachis infection throughout the season.

Sulfur is an effective, inexpensive option. You can alternate with DMIs, Quintec, or Endura. Use shorter spray intervals for sulfur and do not apply it when temperatures are above 85° F.

If you have actively sporulating PM colonies, a potassium salt product (please see comments at pre-bloom) can be a better option.

If you decide to use mancozeb, be aware of the seasonal limit on the amount of mancozeb you can apply (about 6 sprays at the 4 lb/ac rate; read the label for your formulation) as well as the 66-day PHI


April 2012

Final stretch… late season disease consideration

Botrytis is one of common diseases you see during latter part of the season (esp. at sugar level more than 8%). The development of Botrytis depends on several factors, such as variety, weather, and physical damages to berries. For example, red-fruited varieties are relatively resistant compared to white varieties. Also, tight-cluster varieties such as Vignole tend to have higher incidence of Botrytis than loose cluster varieties. This disease can cause infection in a relatively short time (a few hours under optimal condition, 60-70F); however, in the field, it is often associated with a long (>15 hours) of wetness of very high (>98% or so) relative humidity condition. Botrytis pathogen also takes an advantage of wounding events (birds, yellow jackets, other insects, etc.). In addition, when berries are infected at immature stage by powdery mildew, the skin will be damaged, and as the berries get mature, the infected skin will erupt because the dead skin tissue cannot expend. Then Botrytis can come into the wound. Since Botrytis materials (Flint, Pristine, Rovral/Meteor, Vangard, Scala, Switch, etc) do not have curative activity, we recommend applying one of these chemicals at bunch closure to ensure the penetration of the chemical into the cluster, plus at veraison because spores tend to be released around veraison.

You may also be concerned about sour rot. In general, sour rot control need to be based on general vine management because it is typically initiated with a wounding event (insect, bird, hail, etc). Thus, the first question is whether they have issue with yellow jackets or birds in their vineyards. If they do, management of insects and birds will be the first priority.

At this point, your berries are out of susceptible period from downy mildew infection. However, late season rains (such as the ones we had in 2011) can create environmental condition for downy mildew to cause infection on leaves. Severe infection of downy mildew can cause defoliation, and you probably do not want to loose your leaves just before the harvest. Since downy mildew tends to infect younger susceptible leaves first, you can monitor young leaves for the development. For kick-back activity, you can use Ridomil Gold Copper (note: it also have 42-day PHI), or Phosphorous acid materials such as Prophyt or Agri-Fos (0-day PHI). However, please keep in your mind that kick-back activity is for on-going infection, but not for already established colonies (i.e., if you see downy growth, these are established colonies). If there are only minor colonies, you may able to keep them contained in the small area by applying these materials. If you have an outbreak of downy on cluster, Phosphorous acid material mixed with captan is recommended.


April 2012



Comments

Additional cover sprays at 10–14 day intervals

The same as third post-bloom spray

Or Fixed copper product

PLUS one of the following for Botrytis at bunch closing,

veraison, and preharvest (as needed):

Trade name Rate per A

Elevate 0.5-1 lb Rovral (Meteor) 2 pt

Scala 18 fl oz Switch 11-14 oz

Vangard 10 oz

OR

Use Endura at 8 oz/A as part of PM program or use Pristine @ 12.5-23 oz/A alone (please see the note on page 21 about Pristine at higher rates.)

At bunch closing, veraison, and preharvest, you need to consider Botrytis control, especially on bunch rot-prone varieties. Keeping a good ventilation around bunches by proper leaf removal is critical for Botrytis control.

For the rest of the season, keep scouting for DM and PM in your vineyard. You need to adjust spray program according to the weather, the varieties you are growing, diseases observed, and anticipated harvest date. Severe leaf infection of PM and DM can also affect development of winter hardiness.

Fixed copper product will provide good control of both DM and PM. However, It is recommended to avoid captan, sulfur, or copper fungicide within 30 days of the expected harvest date. It may affect wine quality. Be aware of the pre-harvest interval (PHI)!


April 2012

Table 3 A-E. Relative Effectiveness of Selected Fungicides on Grape Diseases The chemicals are sorted based on the estimated level of efficacy against the target disease and then FRAC code (or chemical class/group). If the chemical belongs to the same FRAC code, the specific mode of action will be the same (i.e., you should not use fungicides with the same FRAC code as an option of rotation). If you would like to see a simple alphabetical list of chemicals, please refer to VT’s PMG (Pest Management Guide).

Key: E=excellent; G=good; F=fair; P=poor, N=none or not labeled, L= Labeled and efficacy needs to be examined, FRP = Fungicide Resistance Possible, please refer to table 4, * = at higher rate, please refer to the label

Table 3 A. Black Rot materials

Brand name Common name FRAC code

Black rot

Downy mildew

Phomopsis cane & leaf

spot Powdery mildew

Botrytis bunch rot

Abound Azoxystrobin 11 E G–E (FRP) G G–E (FRP) P

Adament Tebuconazole + Triflozystrobin 3+11 E F-G (FRP) F-G F (FRP) F

Elite, Orius Tebuconazole 3 E N N E (FRP) N

Ferbam Ferbam M3 E P P N N

Flint Trifloxystrobin 11 E F–G (FRP) F–G E (FRP) F,E*

Gavel Mancozeb + Zoxamide M3+22 E G-E G-E N G-F

Luna Experience*

Fluopyram + Tebuconazole 7+11 E N N G-E (FRP) G (L)

Rally (Nova) Myclobutanil 3 E N N E (FRP) N

Sovran Kresoxim-methyl 11 E F–G (FRP) F E (FRP) F

Ziram Ziram M3 E G G N N

Pristine Boscalid + Pyraclostrobin 7+11 E (L) E (FRP) F E (FRP) F, E*

Qadris Top Difenoconazole + Azoxystrobin 3+11 E (L) G-E (FRP) F-G E (FRP) G-E (FRP)

Revus Top Mandipropamid + Difenoconazole 40+3 E (L) E F-G (L) G-E (FRP) N

Dithane, Manzate, Penncozeb Mancozeb M3 G G–E G–E F N Ridomil Gold MZ

Mefenoxam + Mancozeb 4+M3 G E (FRP) P N N

Inspire Super Cyprodinil + Difenoconazole 9+3 G (L) N N G-E (FRP) G-E

Mettle Tetraconazole 3 G (L) N N G-E (FRP) N Rubigan, Vintage ** Fenarimol 3 F N N E (FRP) N

Captan, Captec Captan M4 F–G G–E G–E N P * Newer materials, it may or may not be available in 2012 ** This product has been removed from the market. You can legally use it as long as you keep and follow the label


April 2012

Table 3 B. Downy Mildew materials


Black rot

Downy mildew


spot Powdery mildew

Botrytis bunch rot

Presidio Fluopicolide 43 N E N N N


Zampro* Ametoctradin + Dimethormorph 45+40 N E N N N

Forum Dimethormorph 40 N E (FRP) N N N

Tanos Famoxadone + Cymoxanil 27+11 N E (FRP?) N N N


Ridomil Gold Copper

Mefenoxam + Copper 4+M3 P E (FRP) P F-G P

Ridomil Gold MZ

Mefenoxam + Mancozeb 4+M3 G E (FRP) P N N


Ranman Cyazofamid 21 N G-E (FRP) N N N

Revus Mandipropamid 40 N G-E N N N


Captan, Captec Captan M4 F–G G–E G–E N P Dithane, manzate, Penncozeb Mancozeb M3 G G–E G–E F N Phostrol, ProPhyt, Agri-Fos Phosphorous acid 33 N G–E N N N

Abound Azoxystrobin 11 E G–E (FRP) G G–E (FRP) P

Fixed copper with lime Copper M1 P G P F-G P

Reason Famoxadone 27 N G? (FRP) N N N



Flint Trifloxystrobin 11 E F–G (FRP) F–G E (FRP) F,E*

Sovran Kresoxim-methyl 11 E F–G (FRP) F E (FRP) F * Newer materials, it may or may not be available in 2012


April 2012

Table 3 C. Phomopsis materials


Black rot

Downy mildew

Phomopsis cane & leaf spot

Powdery mildew

Botrytis bunch rot


Captan, Captec Captan M4 F–G G–E G–E N P Dithane, manzate, Penncozeb Mancozeb M3 G G–E G–E F N

Abound Azoxystrobin 11 E G–E

(FRP) G G–E (FRP) P


Adament Tebuconazole + Triflozystrobin 3+11 E

F-G (FRP) F-G F (FRP) F

Qadris Top Difenoconazole + Azoxystrobin 3+11 E (L)

G-E (FRP) F-G E (FRP) G-E (FRP)


Flint Trifloxystrobin 11 E F–G

(FRP) F–G E (FRP) F,E*


Sovran Kresoxim-methyl 11 E F–G

(FRP) F E (FRP) F

Topsin-M Thiophanate-methyl 1 P N F G-E (FRP) F Table 3 D. Botrytis materials


Black rot

Downy mildew


spot Powdery mildew

Botrytis bunch rot

Elevate Fenhexamid 17 N N N P-F E Switch 62.5WG

Cyprodinil + Fludioxonil 9+12 N N N N E

Rovral/Meteor Iprodione 2 N N N N E (FRP)

Scala Pyrimethanil 9 N N N N E

Vangard Cyprodinil 9 N N N N E

Endura Boscalid 7 N N N E F, E*


Flint Trifloxystrobin 11 E F–G (FRP) F–G E (FRP) F, E* Luna Experience

Fluopyram + Tebuconazole 7+3 E N N G-E (FRP) G (L)

Inspire Super Cyprodinil + Difenoconazole 9+3 G (L) N N G-E (FRP) G-E




Sovran Kresoxim-methyl 11 E F–G (FRP) F E (FRP) F

Topsin-M Thiophanate-methyl 1 P N F G-E (FRP) F


April 2012

Table 3 E. Powdery Mildew materials


Black rot

Downy mildew


spot Powdery mildew

Botrytis bunch rot

Endura Boscalid 7 N N N E (FRP,

unknown) F, E*


Luna Experience*

Fluopyram + Tebuconazole 7+3 E N N E (FRP) G (L)

Inspire Super Cyprodinil + Difenoconazole 9+3 G (L) N N E (FRP) G-E

Vivando Metrafenone U8 N N N G-E (FRP unknown) N

Topsin-M Thiophanate-methyl 1 P N F G-E (FRP,

wide spread) F

Elite, Orius Tebuconazole 3 E N N G-E (FRP) N

Flint Trifloxystrobin 11 E F–G

(FRP) F–G G-E (FRP) F, E*

Procure Triflumizole 3 N N N G-E (FRP) N

Quintec Quinoxyfen 13 N N N G-E (FRP) N Rubigan, Vintage ** Fenarimol 3 F N N G-E (FRP) N

Sovran Kresoxim-methyl 11 E F–G

(FRP) F G-E (FRP) F

Mettle Tetraconazole 3 G (L) N N G-E (FRP) N


Qadris Top Difenoconazole + Azoxystrobin 3+11 E (L)

G-E (FRP) F-G G-E (FRP)

G-E (FRP)

Torino* Cyflufenamid U6 N N N G-E (FRP) N

Abound Azoxystrobin 11 E G–E

(FRP) G G–E (FRP) P

JMS Stylet Oil Spray oil NC N N N G N

Sulfur (various) Sulfur M2 N N N G N

Rally (Nova) Myclobutanil 3 E N N G (FRP) N

Adament Tebuconazole + Triflozystrobin 3+11 E

F-G (FRP) F-G F-G (FRP) F

Fixed copper with lime Copper M1 P G P F-G P Ridomil Gold Copper

Mefenoxam + Copper 4+M3 P E (FRP) P F-G P

Armicarb, Kaligreen

Potassium bicarbonate M N N N F–G N

Dithane, Manzate, Penncozeb Mancozeb M3 G G–E G–E F N

Nutrol Potassium phosphate M N N N F N

Oxidate Hydrogen Dioxide M P P P F P * Newer materials, it may or may not be available in 2012 ** This product has been removed from the market. You can legally use it as long as you keep and follow the label


April 2012

Table 4. Resistance-prone Fungicides and Risk of Resistance by Chemical Class Mode of Action Fungicide class Trade name(s) Common (chemical) name(s) Risk Mitosis and cell division Benzimidazole (Group 1) Topsin-M thiophanate-methyl High

Benzamides (Group 43) Presidio fluopicolide Medium Nucleic acid synthesis Phenylamide (Group 4) Ridomil Gold mefenoxam High

Ridomil Gold/Copper mefenoxam (+ copper)

Ridomil Gold MZ mefenoxam (+ mancozeb)

Signal transduction Dicarboximide (Group 2) Rovral (Meteor) iprodione

Medium to High

PhenylPyrroles (PP)(Group 12) Switch fludioxonil (+ cyprodinil)

Quinolines (Group 13) Quintec quinoxyfen Medium Sterol biosynthesis in membrane

DeMethylation Inhibitors (DM), or Sterol inhibitors (Group 3) Elite tebuconazole

Medium, resistance known in various fungal species

Luna Experience tebuconazole (+fluopyram)

Inspire Super difenoconazole (+ cyprodinil)

Procure triflumizole

Quadris Top difenoconazole (+ azoxystrobin)

Quash metconazole

Rally (Nova) myclobutanil

Revus Top difenoconazole (+ mandipromamid)

Rubigan fenarimol

Hydroxyanilid (Group 17) Elevate fenhexamid Medium

CaptEvate fenhexamid + captan

Respiration Carboxamide (anilide) (Group 7) Endura boscalid

Medium to High, resistance known in many fungal species

Luna Experience fluopyram (+ tebuconazole)

Pristine boscalid (+ pyraclostrobin)

Quinone outside Inhibitors (QoI) or Strobilurin (Group 11) Abound azoxystrobin

High, resistance known in various fugal species, cross resistance across all members of the QoI group

Flint trifloxystrobin

Pristine pyraclostrobin (+ boscalid)

Quadris azoxystrobin

Quadris Top azoxystrobin (+ difenoconazole)

Sovran kresoxim-methyl

Quinone x Inhibitor (QxI)(Group 45) Zampro ametoctradin (+dimethomorph)

Medium to High


April 2012

Mode of Action Fungicide class Trade name(s) Common (chemical) name(s) Risk Amino acid and protein synthesis

Anilino-Pyrimidine (AP)(Group 9) Inspire super cyprodinil (+ difenoconazole)

Medium, resistance known in Botrytis Scala pyrimethanil

Switch cyprodinil (+ fludioxonil)

Vangard cyprodinil Lipids and membrane synthesis

Caroboxylic Acid Amides (CAA)(Group 40) Revus mandipropamid

Medium, resistant isolate development in Europe, risk of cross resistance between all CAA group

Revus Top mandipromamid (+ difenoconazole)

Zampro dimethomorph (+ ametoctradin)

Actin disruption (proposed)

Benzophenone (Group U8) Vivando metrafenone

Unknown, less sensitive isolate has been detected

Unknown Amidozimes (Group U6) Torino cyflufenamid

Unknown, Resistant isolate development in Europe

Multi-site contact activity inorganic (Group M1) Kocide, etc copper Low

inorganic (Group M2) sulfur Low

dithiocarbamates and relatives (Group M3)

Dithane, Manzate, Penncozeb mancozeb, etc Low

Ziram ziram, etc

phthalimides (Group M4) Captan captan Low

Not-classified Diverse (Group NC)

mineral oils, biological agents

mineral oils, potassium bicarbonate, other biological materials Unknown

The fungicide resistance risk information is based on known history of development of fungicide resistance, which may or may not be from grape production. If fungicides belong to a class, it is prudent to assume that the resistance rating will be applied for all formulations within the class regardless of differences in common names and trade names. Also, once a fungal species becomes resistant to one chemical group, the resistant isolate can be resistant to others that have the same mode of action (cross resistance). Fungicide groups with medium or high risk of resistance development must be used in accordance with resistance management guidelines listed on the label or labeling.

Please refer to page 6 for more detailed discussions on resistance management


April 2012

Final note

− This information is merely a set of suggested guidelines and your spray program has to be arranged for your vineyard. Variety, site, vine training, history, budget, etc, all have to be incorporated into your spray program.

− This information is a supplement, but not a replacement of the existing spray guide from

Virginia Tech. Virginia Tech’s fungicide and insecticide spray guideline for grape can be found at http://pubs.ext.vt.edu/456/456-017/Section-3_Grapes-2.pdf.

− Finally, please read and follow the fungicide label. The label should provide information

on allowable usage rate, cautions and restrictions on use, and recommendations on fungicide resistance management strategies.

− If you have any questions or suggestions in regard to this guideline, please contact:

Mizuho Nita, Ph. D.

Research/Extension Grape Pathologist Virginia Tech, Alson H. Smith, Jr.

Agricultural Research and Extension Center 595 Laurel Grove Rd. Winchester, VA 22601

Phone: 540-869-2560 ext. 33

Email: [email protected]

Acknowledgement Virginia Tech Dr. Tony Wolf: AHS Jr. AREC, Winchester, VA Dr. Anton Baudoin: Department of Plant Pathology, Physiology, and Weed Science, Blacksburg, VA Other institutions Dr. Mike Ellis: Department of Plant Pathology, The Ohio State University, Wooster, OH Dr. Anne DeMarsay: formerly at University of Maryland Dr. Wayne Wilcox: Department of Plant Pathology, Cornell University, Geneva, NY The backbone of the guideline is based on previously published recommendations from Drs. Baudoin, Ellis, DeMarsay, and Wilcox. Tables 1 and 2 are modified from previously published tables of Drs. Ellis, and DeMarsay, respectively, and table 3 was modified from a work of Mr. Robert Ramsey (a grower from Wintergreen, VA). Pictures of vines are taken from K.W. Eichhorn and D.H. Lorenz (1977) Phanologische Entwicklungsstadien der Rebe, published in Braunschweig, Federal Republic of Germany


April 2012

Appendix

Other noteworthy news: − You may see generic fungicide products containing tebuconazole (Elite) because the patent has

expired. o Adament. It is a new combination product with tebuconazole (the active ingredient in Elite)

and triflozystrobin (the a.i. in Flint). The ratio of the a.i. is 1:1; thus, 2 oz of Adament contains the same quantity of a.i. of 1 oz of Elite and 1 oz of Flint. With the given recommendation rate, it will be about 40-50% of the recommended rate of Elite, thus, it is probably not high enough to provide good control of powdery mildew, especially if sterol-inhibitors have been used for a long time in the same field. Both active ingredients have good efficacy against black rot; thus, Adament should be a good tool for controlling black rot.

− Higher rate of Pristine (18.5 – 23 oz/A) has been registered for Botrytis control. Re-entry interval is 12 hours for all rates. A report from NY indicated that 12.5 oz provides good control of Botrytis.

− A report from NY showed that JMS Stylet Oil (1.5% concentration) tends to be washed off with rain easily. Thus, if you use JMS Stylet Oil for powdery mildew control, you cannot expect too much of protective activity. You can tank mix with other fungicide, but remember: oil and captan and/or sulfur can damage your vines.

− Nova is now called Rally. The only change is the name on the package and the EPA registration number. You can still use old product as long as you follow the label.

In 2009, there was a shortage in the supply of mancozeb. Plus, some of you are looking for the alternative to mancozeb with one reason of another. The following information describes rationale for choosing alternative to mancozeb:

1) Mancozeb can be used in early in the growing season as a backbone of fungal disease management. Its 66-day pre-harvest interval (PHI) prohibits it from being used later in the growing season. Thus, even without mancozeb, your program during the later growing season (after the 66-day mancozeb PHI) should remain the same, if it has been working well for you.

2) Captan and Ziram are the other protectant fungicides to be considered. In terms of efficacy against major fungal diseases, captan has good efficacy against both Phomopsis and downy mildew, and Ziram is weak for downy mildew control and fair for Phomopsis. Thus, if you have a problem with Phomopsis, captan may assist you better than Ziram. Mancozeb, captan, and Ziram have no efficacy against powdery mildew. Mancozeb has a good efficacy against black rot, but both Captan and Ziram have a weak efficacy against black rot. Therefore, your program needs to adjust for black rot control if either captan or Ziram is used. (i.e., add Rally or Abound or other materials to captan)

3) Thus, if captan is used, it should be combined with other fungicide(s) that provides control against powdery mildew and black rot. It is particularly important during immediate pre-bloom to 4 weeks after bloom which is a critical period for protection against fruit infection.

4) With mancozeb, a fungicide such as Rubigan, Endura, Quintec, and potassium salts has been recommended to add efficacy against powdery mildew. However, these chemicals have weak or no efficacy against black rot. Thus, with captan, a sterol-inhibiting fungicide such as Elite or Rally (Nova) will be a good choice for a tank mix to provide efficacy against both powdery mildew and black rot. If you are concerned about fungicide resistance of powdery mildew against these compounds, then sulfur may be added in addition to a sterol-inhibitor of your choice. (Do not add sulfur if your variety is sulfur sensitive.)

5) It is very important to provide protection against all five major fungal diseases [powdery mildew (PM), downy mildew (DM), black rot (BR), Botrytis bunch rot, and Phomopsis cane and leaf spot (Ph)] in the early growing season. Captan + Elite (or Rally) should provide good protection against all.

6) If you use captan, NEVER mix with a product containing OIL. It will result in a serious vine injury. Please note that some insecticide formulations may contain oil as a carrier.

7) And last, but not least, cultural practices to keep canopy well ventilated are the key for preventing development of many plant diseases.

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