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Viticulture Notes
Vol. 14 No.2, May - June 1999
Dr. Tony K. Wolf, Viticulture Extension Specialist
I. Attention
II. Disease management considerations (pre-bloom to mid-summer)
A. Fungicide registrations and news:
B. Powdery Mildew (PM) Reminders
C. Black Rot (BR) Reminders
D. Downy Mildew (DM) Reminders
E. Botrytis Bunch Rot
F. Phomopsis (Ph) Reminders
G. Putting It All Together
1999 Pest Management Guides:
Pest Management Guides are updated
annually by Virginia Tech pest management specialists. Grape specialists
include Drs. Baudoin (plant pathology), Derr (weeds), and Pfeiffer (insects
and mites). The Guide lists common pests, currently recommended pesticides,
as well as specific information on the pesticides (relative efficacy,
rates of application, formulations, pre-harvest intervals, restricted
re-entry periods, etc.). The Guides present the information in a seasonal
fashion; however, they do not attempt to provide a "recipe" for how often
you should spray. The first 40+ pages of the Guides are devoted to
pesticide regulations and safety information. Pesticide recommendations
for grapes can be obtained by purchasing the Horticultural and Forest
Crops 1999 Pest Management Guide (public. # 456-017). It is available
for $16.00 (payable "Treasurer, Virginia Tech") by writing: VCE
Distribution Center, 112 Landsdowne St., Blacksburg VA 24061.
Diagnostic services:
Certain diagnostic laboratory services are provided
by specialists at Virginia Tech. A summary of available services can be
found at Virginia Cooperative Extension's intranet web site: http://www.
ext.vt.edu/vce/specialty/diagnose.html.
The web site provides a brief description of the service, the associated
costs, as well as special instructions for sample submission. Services
include insect identification, analysis of pesticide residues, plant
disease and plant identification, weed identification, and soil testing.
Check it out. Also of interest is Virginia Tech's web site for weed
identification: http://www.ppws.vt.edu/weedindex.htm.
The site has excellent color plates of common weeds at various stages of
plant development.
Meetings:
Please take note of the Virginia Vineyards Association's
annual meeting description at the end of this document.
This promises to be an enlightening
experience for seasoned and novice alike.
II. Disease management considerations (pre-bloom to mid-summer):
The following discussion was kindly contributed by Dr. Wayne Wilcox, Professor of Plant Pathology at Cornell University's NYS Agricultural Experiment Station in Geneva, NY. Dr. Wilcox was a keynote speaker at our January 1999 meeting in Roanoke. While geared primarily towards Finger Lakes area grape producers, the discussion is also applicable to producers in Virginia. My thanks also to Dr. Anton Baudoin, who provided editorial input.
A. Fungicide registrations and news:
Vangard (cyprodinil). Vangard is effective only against Botrytis, but has performed very well in our trials over the last 3 years, providing the same level of control as Rovral (which means that it's no silver bullet, either). It's important to note that we do not have Rovral resistance in our test block; thus, in vineyard blocks where Rovral has been used regularly for a number of years and where it seems to be slipping, Vangard might offer improved control. Incorporating Vangard into your Botrytis control program should help maintain the future effectiveness of Rovral, but it won't replace Rovral completely. For the sake of keeping both compounds effective, they should be rotated and/or tank-mixed until new fungicides and/or regulations are implemented. Vangard is highly prone to Botrytis resistance, therefore it is labeled for a maximum of two applications per season, one application at early bloom and a second application at berry touch, veraison, or pre-harvest. The preharvest interval for Vangard is 7 days, the re-entry interval is 12 hr. The labeled rate for Vangard is 10 oz/A when used alone, or 5 to 10 oz/A when used in a tank-mix with another registered Botrytis fungicide; right now, Rovral is the only fungicide that I'd consider effective enough to tank mix with it for reliable results. In New York State trials, we've gotten equivalent control using Vangard at 10 oz alone or 5 oz mixed with 1 pound of Rovral 50WP (equivalent to 1 pt of the 4F formulation). The 5 oz rate by itself didn't do the job. Vangard, according to one source in Virginia, is currently selling for approximately $3.30/oz, which should provide a tangible incentive to avoid excessive usage if the resistance-management concept doesn't. Vangard is a systemic fungicide (resists washoff) and has shown limited (48-hr) post-infection activity against other diseases on other crops. It is classified as a "reduced risk" fungicide by the EPA due to its favorable environmental and toxicological properties.
Abound. (a) The re-entry interval has been shortened to 4 hr (it was 12 hr previously). (b) In our botrytis control trial last year, we were surprised to find that Abound provided 80% control of botrytis when used by itself at bloom, bunch closing, veraison, and preharvest. I wouldn't count on Abound for botrytis control (nor is it specifically labeled for such), and I want to see these results repeated to be certain that last year wasn't a fluke. Still, if you're using Abound to control other diseases during the bloom through bunch closing period, you might get some additional botrytis control as a bonus.
Elite (tebuconazole). (Editor's notes: Elite 45 DF recently received federal and Virginia state registration for use on grapes. This is a supplemental label, which must be in the possession of the user at the time of application. The activity spectrum of Elite against grape diseases is very similar to that of Nova: excellent activity against powdery mildew and black rot (including BR after-infection activity if applied within 72 hours of the start of an infection period). The label rate is 4 oz per acre, a maximum of 2 lbs may be applied per acre per season, and it may be applied up to 14 days before harvest. Recommended spray interval is 14 days which may be shortened to 7-10 days during early berry growth or under severe disease pressure. Depending upon source, Elite may be up to 25% cheaper than Nova.)
Mancozeb. Evidence is accumulating that establishes a link between the use of mancozeb and the suppression of a "good" mite that feeds on the European red mite. Mancozeb is undeniably a useful and important component in most grape growers' disease control programs, but those who are having trouble controlling mites may want to at least consider experimenting with other fungicide options. (editor's note: we do not know whether the beneficial ["good"] mite that Dr. Wilcox refers to is a significant component of our predator-pest ecology in Virginia vineyards).
Sovran (kresoxim-methyl). This is one of the "Abound-like" fungicides
that also will be registered for use on apples. Federal registration
is still pending, but appears to be imminent. We've worked with Sovran
pretty intensively for the last few years, and here's my comparison of
it versus Abound: a little stronger against powdery mildew, weaker
against downy mildew (probably good enough for moderately susceptible
varieties but I'd be nervous with
B. Powdery Mildew (PM) Reminders:
1. Most berry infections occur during the first few weeks after the
start of bloom. Disease that you see on the berries later in the
season usually is caused by a combination of favorable weather and
problems with the spray program during that time. You've been hearing
this for a couple of years now; it's still true. Do an excellent job
with the immediate prebloom and first postbloom sprays (best materials,
best coverage, etc.), and it will be relatively easy to keep the fruit
clean for the rest of the year; goof up then, and it'll be hard to get
out of the hole.
Concord berries become virtually immune within 3-4 weeks after bloom
starts; vinifera berries lose most of their susceptibility at this same
time, although they do not become fully immune until considerably later.
Susceptible hybrids seem to act like viniferas, e.g., on 'Rosette', we
typically get 90% control of berry infection from just the prebloom plus
first postbloom sprays, whereas we get nearly 100% control on Concords.
Leaves also lose susceptibility as they mature, but new susceptible
tissue is constantly produced so long as the shoots keep growing. On
vinifera and susceptible hybrid varieties, there's a direct relationship
between control of foliar infection and fruit quality (including Brix).
In contrast, Concord fruit are remarkably unaffected by foliar infection
at moderate cropping levels, but they do respond negatively to foliar PM
at higher cropping levels (e.g., 10 tons/A and above).
2. Resistance to SI fungicides is an issue that must be dealt with.
Last year, it became clear that many growers who used Abound in the
immediate prebloom and first postbloom sprays had less PM than those who
relied on the sterol-inhibiting (SI) materials (e.g., Bayleton, Nova,
Procure) during that critical period. This is not to say that the SIs
no longer work; for the most part, they do, but they're less reliable
than they once were and there's less margin for error when using them.
Abound and related fungicides (the strobilurins or "strobies" for short)
are excellent for controlling PM, but they can't be used exclusively.
Already, we are hearing the first reports from Europe and Asia concerning
resistance to these materials on other crops (barley, cucumbers) where
powdery mildews were treated too intensively without adequate resistance
management strategies in place. Our objective should be to maintain the
effectiveness that we still have with the SIs, so that we can use them in
rotational programs with the strobies and keep both chemistries available.
Below are a few reminders with respect to SI resistance management:
(i) Limit SI use, preferably a maximum of three sprays per year, and
rotate with unrelated fungicides (important for the strobies, too).
(ii) Thorough spray coverage is CRITICAL for adequate performance and
resistance management. The surest way to encourage SI resistance is to
use low rates of these fungicides. The surest way to provide low rates
to certain parts of the vineyard is to provide uneven spray coverage.
It really is that simple.
(iii) The SIs will perform much better, and less resistance will develop,
when they're used to combat a small PM population rather than a large one.
Position them early in the season (not an optimal timing for the strobies)
or use them to maintain a clean vineyard mid-season. You're just asking
for trouble if you try to use these materials to clean up or slow down a
PM problem that's already developed (this is true for the strobies, also).
We've seen little difference in efficacy between the various SI fungicides
that are available (Bayleton may be an inferior exception). They're as
effective as Abound where resistance isn't a problem, but less effective
where it is. With JMS Stylet Oil, it's looking like the best time for use
might be in the early season, for two reasons: (i) We've seen some evidence
of Brix suppression with relatively high use rates in the midsummer; and
(ii) Unlike most fungicides, oil has the potential to actually eradicate
early (primary) infections, thus limiting their ability to spread.
However, don't get suckered into thinking that this will happen if you
apply 20 gal/A every other row; Stylet Oil just won't work without
excellent coverage.
1. As with powdery mildew, berries are highly susceptible to BR from
bloom through the early fruit set period, but they become highly
resistant by approximately 4 weeks after the start of bloom. We've
seen this in both years of a trial in which berries of Cayuga White,
Chardonnay, Concord, and Riesling were inoculated at weekly intervals
after bloom. Similarly, in both commercial Finger Lakes vineyards and
local research plots, we've noted much higher BR levels in years when
this period was wet (1995 and 1998) versus those when it was dry (1996
and 1997). So, be extra vigilant with your BR control practices if
conditions are wet in late June and early July; relax a bit if they're dry.
2. Most BR control comes from the immediate prebloom and first two
postbloom sprays. In fact, all of the control obtained in seven out
of eight spray timing trials we've conducted since 1995 has come from
these sprays (i.e., additional sprays applied earlier and later provided
no additional benefit). The remaining trial was conducted in a vineyard
with a history of extensive black rot losses and very high inoculum
levels; in this case, an additional spray 2 wk before the immediate
prebloom application provided an additional measure of control.
3. Mummies (previous year's berries) retained in the canopy provide
more pressure for BR development than those dropped to the ground.
This should be a no-brainer, but it was striking to see how much this
simple practice contributed to disease control when we examined it
side-by-side in a machine-pruned vineyard where mummies had been retained
in the canopy after hedging. That is, where we went in after hedging and
dropped mummies to the ground by hand in certain plots, we ended up with
much less BR than in plots where the mummies were left hanging. Don't
ignore this aspect of sanitation if you're having trouble with BR control.
With respect to BR fungicides: nothing beats Nova (or Elite) for control,
but mancozeb, ferbam, and ziram will do a good job under most conditions.
Abound has been equivalent to mancozeb and ziram in some of our tests, and
a little better in others under high rainfall conditions (it's less likely
to wash off). Sovran has been equivalent to Abound. Copper is poor.
Don't count on Rubigan or Procure.
D. Downy Mildew (DM) Reminders:
Recall that inoculum overwinters in last year's infected leaves on
the vineyard floor. The first spores become mature about 2 to 3 weeks
before bloom, and cause infection during rainy periods when temperatures
are 50&176;F or higher. These primary infections can continue to occur until
about 2 weeks after bloom.
The destructive phase of the disease is caused when spores produced
from primary infections blow through the vineyard and cause repeated
cycles of secondary infections if humid nights are followed by rainy
days. At optimum temperatures of approximately 60 to 80&176; F, this cycle
can repeat itself every 4 or 5 days, allowing an "explosive" disease
epidemic when favorable weather conditions persist. Young fruit are
highly susceptible to infection, but appear to lose susceptibility quite
quickly with age, much as with PM and BR. For instance, on 'Chancellor'
(extremely susceptible fruit), we usually get 85-90% control with just
two applications of Abound in the immediate prebloom and first postbloom
spray.
General control strategies are:
(i) DM sprays should start on highly
susceptible varieties about the 10-inch shoot growth stage (i.e., 2 to
3 weeks before bloom) unless the vineyard was very clean last year or
you're sure it won't rain before the next spray.
(ii) All but the most resistant vineyards should receive a DM fungicide
in the immediate prebloom and first postbloom sprays unless the weather
is bone dry. This is the critical time to protect against fruit infection.
(iii) By the time the first postbloom spray wears off, primary inoculum is
pretty well shot and the need for additional treatments should be based on
the usual array of factors: presence or absence of established disease in
the vineyard, weather, and variety. Typically, DM "goes on vacation"
during much of July (many of the spores that spread the disease probably
are killed by the spate of hotter, dry weather that we usually get at
that time), then it reactivates as days get shorter and nights get dewier
in August.
Ridomil remains the "Cadillac" material, in both performance and cost.
However, its lack of activity against other diseases and the new
availability of Abound will probably relegate it to "rescue treatment"
status even more so than before. In our trials, Abound has been
excellent, equal to mancozeb in some trials and better in others (e.g.,
when the first spray was applied late or in high rainfall years).
Copper, mancozeb, and captan are old standards for a good reason: they work.
As in 1994 and 1996, our 1998 spray timing trials showed that Rovral
applied at bloom and bunch closing provided additional control when
they were added to the "traditional" sprays at veraison and 2 weeks
later (note that all three of these years were wet during the bloom
and early postbloom periods). Last year, in fact, treatments applied
only at bloom and bunch closing were as effective as those applied
only at the "traditional" times. There are many good reasons not to
apply Botrytis fungicides at bloom and bunch closing: they're frequently
not necessary, they're expensive, and reducing the number of seasonal
applications is important for fungicide resistance management. It's
clear that in the majority of years, the period between veraison and
harvest is the most important for control of the disease, and this
should remain the period of primary emphasis. Of course, specific
timings should be juggled during these periods (within label constraints)
to provide protection during wet spells and ease up when it's dry.
However, it's also clear that the bloom through early postbloom period
can be important for controlling Botrytis if the weather is wet during
that time. Those with "problem" varieties and sites might want to
consider this option if they're looking to improve their Botrytis
control programs.
The new registration of Vangard (see discussion above), the pending
registration of additional (unrelated) Botrytis fungicides, and the
apparent Botrytis activity of Abound and other strobies are providing
significant new options to improve Botrytis control, but they won't be
cheap.
't ignore the relationship between berry moth
damage and Botrytis infection. Those "problem" rows near the woods
often owe more to the infection of berry moth injury sites than they
do to the extra shading that might get blamed. Of course, the importance
of providing good air circulation via cultural practices (leaf pulling,
shoot positioning, etc.) shouldn't even require a reminder.
Although the economic losses from the early season stage of Phomopsis
are questionable, they can be serious if the early season is wet and
new shoots are unprotected. Furthermore, the canes, spurs, or pruning
stubs that originate from infected shoots eventually serve as the
primary source of inoculum for economically-important rachis and fruit
infections in later years. Bottom line: it's an easy disease to
control and worth it over the long haul.
Fruit become infected by Phomopsis when frequent rainfall occurs
during the bloom through pea-sized berry period, although infected
fruit do not show symptoms until near harvest (symptoms resemble those
of black rot, and the two diseases are difficult to tell apart on the
fruit). The most important time for rachis infection appears to be
from the early period of cluster emergence until several weeks after
bloom. The risk of Phomopsis losses (and the relative need to control
them) can be judged to some extent by (i) the recent history of the
disease (an indication of the inoculum potential in the vineyard);
(ii) the pruning and training system (shoots, rachises, and fruit
that develop beneath old spurs and pruning stubs are at greatest
risk); and (iii) the weather (frequent and/or prolonged rains).
Mancozeb, captan, and ziram have all provided good control of the
basal shoot infections in our fungicide trials. Abound and other
strobies have not done as well, and Nova did nothing (probably true
for the other SI fungicides as well).
There are many good programs for controlling the common grape
fungal diseases. Here are a few considerations. Just because it
isn't listed here doesn't mean it's a bad idea. For example,
Virginia readers have the option of substituting Elite for Nova
wherever Nova appears; Sovran also may become an optional substitute
for Abound during the 1999 season (recognizing the downy mildew
weakness). Abbreviations: Ph = Phomopsis; PM = Powdery mildew;
BR = Black rot; DM = Downy mildew.
1-INCH SHOOT GROWTH. A Ph spray may be warranted if wet weather
is forecast and the training system or recent block history suggests
high risk.
Option A: Nothing.
3-5 INCH SHOOT GROWTH. A traditional time to control Ph shoot infections;
early rachis infections also are possible now. Time to start control
of PM in vinifera and some hybrid blocks (where crop value justifies it).
BR control is unlikely to be justified unless disease was severe
last year AND weather is wet. Even less necessary to control BR now
if Nova will be used in the next spray.
Option A: Nothing.
10-INCH SHOOT GROWTH. Traditionally, we've recommended you wait
no longer to control BR. Continued experience tells us that this
recommendation is conservative (the spray generally isn't needed)
unless BR was a problem last year and/or weather is unusually wet.
Don't wait any longer to control PM on susceptible varieties. DM
control will be needed on highly susceptible varieties if disease
was prevalent last year and rains of at least 0.1 inches at
temps >50&176;F occur. Rachis infections by Ph are a possibility,
particularly if weather is wet.
Option A: Abound (PM, BR, DM, Ph?).
Label allows only two sequential sprays before alternation with
other materials, thus spraying now will not allow use in both of
the following two sprays, which are the most critical ones of the
year.
IMMEDIATE PREBLOOM (OR VERY EARLY BLOOM). A critical time for PM,
BR, DM, and Ph (rachis and fruit infections). Also important for
ALS on susceptible varieties (editor's note: ALS has not been a
significant, recognized problem in Virginia vineyards). This and
the first postbloom spray are the most critical sprays of the
season--DON'T CHEAT ON MATERIALS, RATE, OR COVERAGE!
Option A: Abound (PM, BR, DM, Ph). The best choice if SIs seem to be
slipping against PM and multiple disease control is needed. Even
if no problems yet with the SIs, a good choice to reduce
resistance-development pressure. May provide some Botrytis control
if bloom period is wet. Cheaper than Option B at typical rates.
BLOOM. Rovral or Vangard for Botrytis control may be beneficial
in certain years if weather is frequently or persistently wet.
See previous discussion.
FIRST POSTBLOOM. Still the most critical period for PM, BR, DM,
and Ph (rachis and fruit). Same Options and considerations as
detailed under IMMEDIATE PREBLOOM. Juice grape growers can
substitute Ziram (very good BR and Ph, only fair DM) for mancozeb
if necessary.
SECOND POSTBLOOM. BR control still may be needed if disease was
present last year or is visible this year, especially if weather
is wet. Fruit are less susceptible to PM now, but vinifera
varieties (and susceptible hybrids?) still need protection.
Rachises and foliage remain susceptible. Ph danger is mostly over
unless very wet. Primary DM should be over, but continued protection
may be needed on susceptible varieties if weather is wet, especially
if disease already is established.
Option A: Abound (PM, DM, BR, Ph).
Not an option if used in the previous two sprays. Provides good residual
control if used now.
ADDITIONAL SUMMER SPRAYS. Check the vineyard regularly to see what's
needed, the main issues will be PM and DM. On vinifera
and other cultivars requiring continued PM control, use sulfur as an
economical
choice to maintain control (weather and variety sensitivity permitting);
SIs and Abound are options if they haven't been overused earlier AND
little disease is evident. Both provide the advantage of longer
residual activity than sulfur, especially in wet weather. Copper +
lime will work for Concords. For DM, copper + lime or captan are
economical standards; Abound is a viable option if general disease
pressure or other conveniences justify its cost; Ridomil can be used
in case of emergency, but watch out for the 66-day preharvest
restriction. BR should not be an issue after the second postbloom
spray. Ph should not be an issue. See previous discussion for
Botrytis at bunch closing, veraison, and preharvest.
III. Vineyard labor issues: Part 2:
The following article is the second installment of a multi-part
section on farm labor issues (Part I was featured in the
March-April
1999 Viticulture Notes. The information is provided by Lynette Wills
of the Virginia Employment Commission.
This month we will be providing information on two other Farm
Placement Specialists employed by the VEC. Veronica Weis works in
the Charlottesville office and has been with the agency for 6 years.
Her service delivery area includes the following counties: Culpeper,
Orange, Madison, Greene, Albemarle, Nelson, Fluvanna, Buckingham,
Amherst, and Lousia. Ronnie may be reached at 804-984-7630 or by
e-mail at eln/vec018rl@earthlink.net.
Dave Kaleta is one of two Farm Placement Specialists in the Exmore
local office. Exmore serves Northampton and Accomack counties.
Dave has been with the VEC for three years and serves agricultural
employers and migrant and seasonal farm workers. Dave may be reached
at 757-442-6176 or at vec013r2@erols.com.
FIELD SANITATION
The Field Sanitation Standard requires employers of 11 or more field
workers to be provided toilets, potable drinking water, and hand-washing
facilities to hand laborers in the field. The effective dates of this
standard were May 30, 1987 for potable drinking water and July 30, 1987
for toilets and hand-washing facilities. The standard may be found at
Virginia Part 1928, Subpart 1.
This section applies to all agricultural establishments where eleven
(11) or more employees are engaged on any given day in hand-labor
operations in the field. Once an employer has had eleven or more
employees in the field at any given time, then the regulations require
Field Sanitation be present through out the remainder of that year.
Hand labor operations means agricultural activities or agricultural
operations performed by hand or with hand tools. Some examples of
hand labor operations are the hand-cultivation, hand-weeding,
hand-planting and hand-harvesting of vegetables, nuts, fruits,
seedlings or other crops, including mushrooms, and the hand-packing
of produce into containers, whether done on the ground, on a moving
machine or in a temporary packing shed located in the field.
Hand-labor does not include such activities as logging operations,
the care or feeding of livestock, or hand-labor operations in
permanent structures such as canning facilities or packing houses.
Hand-washing facility means a facility providing either a basin,
container, or outlet with an adequate supply of potable water, soap
and single-use towels.
Potable water means water that meets the standards for drinking
purposes of the state or local authority having jurisdiction of
water that meets the quality standards prescribed by the U.S.
Environmental Protection Agency's National Interim Primary Drinking
Water Regulations, published in 40 CFR Part 141.
Toilet facility means a fixed or portable facility designed
for the purpose of adequate collection and containment of the
products of both defecation and urination which is applied with
toilet paper adequate to employee needs. Toilet facility includes
biological, chemical, flush and combustion toilets and sanitary
privies.
Agricultural employers shall provide the following for employees
engaged in hand-labor operations in the field, without cost to the
employee:
A. Potable Drinking Water
B. Toilet and hand-washing facilities.
C. Maintenance
Potable drinking water and toilet and hand-washing facilities
shall be maintained
in accordance with appropriate public health sanitation practices,
including the following:
D. Reasonable use.
The employer shall notify each employee of the location of the
sanitation facilities
and water and shall allow each employee reasonable opportunities
during the workday to use them. The employer also shall inform
each employee of the importance of each of the following good
hygiene practices to minimize exposure to the hazards in the
field of heat, communicable diseases, retention of urine and
agrichemical residues.
Information for this article was obtained from several sources
including the Fact Sheet OSHA'S Field Sanitation Standard, and
Part 1928. 110 (c).
The form following this article may used by employers to verify
workers have received information on good hygiene practices as
required under the Field Sanitation Standard.
16-18 June 1999
14-18 July 1999
24 July 1999 (Saturday):
Program:
8:30-9:00: Registration at Breaux Vineyards (540-668-6299).
Directions: Rt 7 west from Leesburg to Rt 9 west (Hillsboro exit).
Take Rt 9 west 9.5 miles to right on Rt 671 (Harpers Ferry Rd.).
One mile north on Rt 671 to winery sign on right.
9:00-10:30: Discussions by Paul Breaux (owner) and David Collins
(vineyard manager/wine maker)
10:30: Coach departs for Chrysalis Vineyards, Middleburg
11:00-12:00: Discussion by Jennifer McCloud, owner of Chrysalis
Vineyards
12:00-1:00: Catered lunch (if pre-registered, otherwise, BYO)
1:00-2:00: Technical discussion: Speaker and topic yet to be decided;
however, the topic will likely be on pesticide sprayer technology or
irrigation scheduling
2:00-2:15: Travel to Piedmont Vineyards
2:15-3:15: Discussions of Piedmont vineyards (speaker to be announced)
3:15-4:00: Travel to Arlesa Vineyards, Lovettsville
4:00-4:45: Discussion of Arlesa Vineyards with Lee Sandberg (owner of
Arlesa Vineyard)
4:45: Return to Breaux vineyard and departure
Registration: Cost is $25 per person (VVA or VVA-member's employee) or
$35 for non-VVA member. Contact Tony Wolf at 540-869-2560, extn. 20
and request registration form.
Information: Additional information will be available by mid-June;
contact Tony Wolf (540-869-2560, extn 20, or vitis@vt.edu)
"Viticulture Notes" is a bi-monthly newsletter issued by Dr. Tonly K. Wolf,
Viticulture Extension Specialist with Virginia Tech's Alson H. Smith,
Agricultural Research and Extension Center in Winchester, Virginia. If you
would like to receive "Viticulture Notes" as well as Dr. Bruce Zoecklein's
"Vinter's Corner" by mail, contact Dr. Wolf at:
Dr. Tony K. Wolf
or e-mail: vitis@vt.edu
Commercial products are named in this publication for informational purposes
only. Virginia Cooperative Extension, Virginia Tech, and Virginia State
University do not endorse these products and do not intend discrimination
against other products that also may be suitable.
Visit
Virginia Cooperative Extension.
Visit
Alson H. Smith, Jr., Agricultural Research and
Extension Center.
Option B: Captan or mancozeb.
Option B: Nova (PM, BR). Use the 3 oz rate (about $12/A).
Option C:
Rubigan (PM). At 2 fl oz/A, cost is only about $4/A. Cheaper than
Nova but won't control BR; however, most vineyards won't need BR
control at this time and mancozeb will provide it if applied for Ph.
Option D: Sulfur (PM). Not very active at temps below 60&176;F.
If you
really need this spray, sulfur is a questionable choice unless it's
warm. Doesn't control other diseases.
Option E: JMS Stylet Oil
(PM). Should eradicate young infections IF thorough coverage is
provided. Can use with mancozeb (or ziram), but not with captan or
sulfur (phytotoxicity).
Option F: Mancozeb (BR, Ph).
Option G:
Captan (Ph). Easier on predator mites than mancozeb or ziram, but
not as effective against BR.
Option H: (C or D or E) + F (PM, BR,
Ph).
Option B: Mancozeb tank-mixed with a PM material (BR, Ph, DM).
A broad spectrum, economical choice.
Option C: Nova (PM, BR).
Option D: Rubigan (PM). No BR control but cheaper than Nova.
Option E: JMS Stylet Oil (PM). If (and only if) coverage
is thorough, this spray should eradicate early PM colonies that
may be starting because previous PM sprays were omitted. At a
retail cost of $11/gal, a use rate of 1% (1 gal oil /100 gal water),
and 50 gal/A spray volume, cost is about $5.50/A. Also may help with mites.
Option F: sulfur (PM) Avoid use on sulfur-sensitive varieties.
Option G: Mancozeb (BR, Ph, DM) + a PM material (Nova, Rubigan, Procure,
sulfur, JMS Stylet Oil). Choose PM material based on
previously-discussed characteristics and cost.
Option B: Nova + mancozeb (PM, BR, Ph, DM). Nova is the big gun
against BR, so probably the best choice if pressure is high and BR
control is the most important consideration. Provides postinfection
activity against BR if significant unprotected infection periods
occurred within the previous 4 days.
Option C: Rubigan + mancozeb
(PM, BR, Ph, DM). Cheaper than Options A and B. Mancozeb does a
commercially acceptable job of BR control under most circumstances,
but no postinfection activity if that's needed.
Option D: Mancozeb + sulfur (PM, BR, Ph, DM). Cheap and reasonably
effective but not the strongest choice at a time when the
strongest choice is most justified.
Option B: Nova (BR, PM) + captan or mancozeb
(66-day preharvest restriction) if DM and Ph control are needed.
Option C: Rubigan (PM) + either (a) mancozeb (if more than 66 days
before harvest) for BR, DM, and Ph; or (b) captan (DM, Ph, some BR);
or (c) ziram (BR, Ph, some DM).
Option D: Sulfur (PM) + either
(a) mancozeb (if still allowed) or (b) captan. In most years,
lessening disease pressure makes this economical option increasingly
practical as the season progresses from here on out.
Option E:
Copper + lime (PM, DM). Adequate for American type grapes, but not
enough PM control for vinifera and susceptible hybrid varieties.
Contributed by Ms. Lynette Wills, Farm Placement Specialist, VA
Employment Commission, Winchester, VA 22604, 540-722-3415
at vec004rl@crosslink.net.
ASEV Annual Meeting
Reno Hilton, Reno, NV
American Society for Enology and Viticulture PO Box 1855 Davis,
CA 95617-1855 (530-753-3142)
Oak Symposium and ASEV/ES Annual Meeting
St. Louis, MO
We, 14 JUL 99: Symposium tour, visit an oak forest and barrel
making facilities
Th+Fr, 15- 16 JUL 99: Oak Symposium ‚ Science, practical experience,
and tastings
16 JUL 99: Trade Show and Technical Presentations, Annual Meeting
of ASEV/ES
Sat, 17 JUL 99: Technical Presentations, Annual Meeting of ASEV/ES
Contact: Ellen Harkness, Purdue University, 765-494-6704, or
harkness@foodsci.purdue.edu or
http://www.nysaes.cornell.edu/fst/faculty/henick/asev/
Virginia Vineyards Association Annual Meeting and Vineyard Tour
Annual business meeting and technical program of the Virginia
Vineyards Association. This year's meeting will be unusual in
that the "meeting" will be a round-robin coach tour of 4 northern
Virginia vineyards. Registrants will depart from, and return to
Breaux Vineyard in Loudoun County. Discussions enroute (Tony Wolf
and Lucie Morton) and at each vineyard stop will punctuate the tour.
This will be a splendid opportunity to visit with some of the area's
premier grape and wine producers.
AHS Agricultural Research and Extension Center
595 Laurel Grove Road
Winchester, VA 22602