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April/May 2001, Vol. 13, Nos. 4 and 5
Berry Notes is compiled and edited by Sonia Schloemann. Authors and sources
are cited for all articles. Publication is funded in part by the UMass
Extension Agroecology Program and grower subscriptions. A text version
can be e-mailed to you if you contact Sonia Schloemann at 413-545-4347,
sgs@umext.umass.edu. Please cite the original source if re-printing information.
IN This Issue
MESSAGE FORM THE EDITOR
STRAWBERRIES
- STRAWBERRY FROST PROTECTION
- EASTERN FLOWER THRIPS
- 'SAPHIRE' & 'SERENITY' STRAWBERRIES
- PERFORMANCE OF STRAWBERRIES ON FUMIGATED AND NONFUMIGATED SOIL
BRAMBLES
- NITROGEN FOR RASPBERRIES AND BLACKBERRIES
- A PRICKLEY SUBJECT-BRAMBLES!
BLUEBERRIES
- MUMMYBERRY DISEASE IN BLUEBERRIES
- ASANA INSECTICIDE FOR BLUEBERRIES
- HIGHBUSH BLUEBERRY FERTILIZATION
GRAPES
- GRAPE MEALYBUG
- VEGETATION-FREE AREA SURROUNDING NEWLY PLANTED 'NIAGARA' GRAPEVINES
AFFECTS VINE GROWTH
- GRAPE PEST MANAGEMENT
PEST CONTROL NEWS
- CANCELLATION OF BENOMYL (BENLATE)
- SELECT 2EC FOR STRAWBERRIES
- CHANGES TO SAVEY LABEL
- FOOD POISONING LINKED TO PESTICIDE SPRAYS
- GETTING THE MOST OUT OF GLYPHOSATE
- THAT'S A BERRY GOOD QUESTION!!!
GENERAL
- NEW FARMERS MARKET BOOK
- GET CHOLINESTERASE BLOOD TEST NOW
- GROWER QUESTIONS
Message from the Editor:
Weekly Issues of Berry Notes to Start Soon: The next mailing
of Massachusetts Berry Notes will kick-off the weekly distributions.
This should be around the middle of May and will run for about 10 weeks.
Weekly crop/pest reports and other timely topics will be featured in these
issues.
Error about Ronilan on Raspberries: In last month's newsletter,
it was reported that "Ronilan can no longer be used on raspberries.
Even though you may have a package labeled for use on raspberries, it
can no longer be used on raspberries." Well, that would be true if
this were 2002, but it isn't yet. Ronilan can be used on raspberries until
Sept. 30, 2001. Apologies for any confusion.
Agricultural Business Training Program: Enclosed in this issue
of Massachusetts Berry Notes is a brochure describing a business planning
course for all kinds of Massachusetts farm enterprises. This course was
offered in multiple locations in 2000-2001 and has received very high
marks from participants. If you are interested in signing up for a course
that will be offered near you in 2001-2002, contact Richard Chandler at
413-577-0459.
Excellent websites for grape growers: The Lake Erie Regional Grape
Program has completed it's new website which can be found at: http://lenewa.netsync.net/public/IPM/Home.htm.
Check it out! Also check out the Pennstate Wine Grape Network newsletter
at http://winegrape.cas.psu.edu/grapevine/index.html.
Custom Blueberry Packing: A new laser sorting/packing line located
in Southeastern Massachusetts is looking for custom packing customers.
Please contact me for more information (413-545-4347).
Strawberries
Strawberry Frost Protection
Bruce Bordelon, Purdue University
Strawberries are in bloom in southern and central areas of [Indiana].
Sprinkler irrigation equipment for frost protection should be set up,
tested, and ready to go. Once flowers open they are susceptible to temperatures
below 30šF. Application of water through overhead irrigation can
prevent temperatures from dropping below 30šF even though the air
temperatures may drop to 25šF or colder. The principle behind this
method of frost protection is that as water freezes, heat is released.
As long as an adequate layer of freezing water covers the bud or berry,
the temperature will remain at or near the freezing point. It is important
to remember that a layer of freezing water must be present at all times.
Ice with-out the continued application of water will not protect the flowers
from freezing temperatures. This means that the rate of application of
water must be carefully monitored. The rate at which water freezes is
dependent on several environmental factors including air temperature,
humidity, and wind speed. Generally, the lower the air and dew point temperature,
and/or higher the wind speed, the greater the rate of freezing. Application
rates for frost protection are fairly low compared to normal overhead
irrigation rates. Most growers install a smaller set of nozzles in the
sprinkler head specifically for frost protection. The correct rate of
irrigation can be deter-mined from the following table.
Table 1. Irrigation application rates (inches per hour) for adequate
protection of strawberries at different relative humidity rates.
|
Air temperature at canopy level (°F)
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Wind speed (MPH)
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0-2
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2-4
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5-8
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10-14
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18-22
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At 50% Relative Humidity
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27°
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0.10
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0.20
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0.30
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0.40
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0.45
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24°
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0.10
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0.30
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0.35
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0.45
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0.60
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20°
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0.15
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0.35
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0.45
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0.60
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0.75
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18°
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0.20
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0.40
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0.50
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0.65
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0.85
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At 75% Relative Humidity
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27°
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0.05
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0.10
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0.20
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0.20
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0.25
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|
24°
|
0.10
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0.20
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0.30
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0.35
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0.40
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20°
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0.10
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0.25
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0.40
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0.45
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0.60
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18°
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0.15
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0.30
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0.45
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0.55
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0.70
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Irrigation should be started before damaging tem-peratures occur. Start
irrigation when the temperature in the lowest part of the planting reaches
34šF at canopy level. Continue irrigation until ice begins to melt
after sunrise. Irrigation can be very effective for frost protec-tion,
but it can also create problems such as excessively wet soils, nutrient
leaching, and fruit rots. Misuse of ir-rigation for frost protection can
cause more harm than good. (Source: Facts for Fancy Fruit, April 25, 2001)
Eastern Flower Thrips
Rick Foster and Bruce Bordelon, Purdue University
One of the factors we believe may be associated with problems with eastern
flower thrips on strawberries is having sustained, strong southerly winds
early in the growing season. If any of you have been outside lately (or
tried to spray), you know that we have had a number of days of nearly
continuous strong winds from the south. These winds may well be blowing
eastern flower thrips to Indiana from southern areas. It would be prudent
for strawberries growers to watch for thrips as we approach bloom.
(Source: Facts for Fancy Fruit, April 25, 2001)
'Sapphire' and 'Serenity' Strawberries
Pam Fisher, OMAFRA Canada
Two new strawberry varieties are being released from University of Guelph's
strawberry breeding program in the Department of Plant Agriculture. 'Sapphire'
and 'Serenity' strawberries were developed at the Department's Simcoe
campus from crosses made in 1989 and 1991. Both varieties have been widely
trialled within the province, both at the University's OMAFRA research
stations and on growers farms.
'Sapphire', derived from the cross '319A92' x 'V7737-2' is a late-mid
season variety with high yields of large, bright quality fruits. Its plants
are moderately re-sistant to the diseases, leaf scorch and powdery mildew,
and have shown tolerance to the herbicide terbacil (Sin-bar) on the sandy
soils at Simcoe. Plants will be avail-able from propagators in spring
of 2002.
'Serenity', derived from the cross '137A84' x 'Chan-dler', is a late
season variety with high yields of very large, bright, soft-skinned fruits.
Its plants are moder-ately resistant to the diseases, leaf scorch and
powdery mildew, and have shown intermediately tolerance to the herbicide
terbacil (Sinbar) on the sandy soils at Simcoe. Plants will be available
from propagators in spring of 2003.
For further information contact: Dr. Adam Dale, Department of Plant Agriculture
- Simcoe, University of Guelph, Phone: 519-426-7127, extn. 333, Fax: 519-426-1225.
(Source: All Ontario Berry Grower, Volume #00.3 - March/2001)
Relative Performance of Strawberry Cultivars and Native Hybrids on
Fumigated and Nonfumigated Soil in Michigan
James F. Hancock, Peter W. Callow, and Sedat Serçe, Annemiek C.
Schilder, Michigan State University
Abstract. The performance of four California and 11 eastern cultivars
of Fragaria ananassa Duchesne in La-marck, and 12 elite F1 hybrids of
Fragaria ananassa with F. virginiana Miller in their immediate background
was evaluated in a producer's field with and without methyl bromide-chloropicrin
fumigation. Averaged across all genotypes, plants in nonfumigated soils
had 43% fewer runners, 18% smaller fruit, and 46% lower yields than did
plants on fumigated soil. They also had an average of 27% fewer crowns,
49% more root discoloration, significantly fewer fine roots, and showed
symptoms of the black root rot syndrome. The most commonly isolated pathogens
from discolored roots were Pythium sp., Rhizoctonia sp., Idriella lunata
P.E. Nelson & K. Wilh., and the root-knot nematode (Meloidogyne hapla
Chitwood). The performance of all genotypes was enhanced by fumigation,
although the F. virginiana hybrids performed comparatively better than
the other cultivars on nonfumigated soils.
(Source: HortScience, Vol. 36, No. 1, February 2001, reprinted with permission)
Brambles
Nitrogen for Raspberries and Blackberries
Excerpt from a larger article by Eric Hanson and Jim Nugent, Michigan
State University
Most bramble plantings need annual nitrogen (N) applications. Urea (46%
N), ammonium nitrate (33% N) and calcium nitrate (15.5% N) are suitable
N sources. Nitrogen can also be supplied as a complete fertilizer containing
P and K, such as (12-12-12), or manure, though these sources are often
more expensive than those supplying only N. Use complete fertilizers with
a 1:1:1 or similar ratio if the soil has not been sampled to determine
fertility levels. Fertilize newly set plants two to three weeks after
planting by sprinkling the equivalent of 15 to 20 lbs N per acre (1/2
lbs N/100 feet of row) around individual plants, keeping the fertilizer
3 to 4 inches away from the base of the plants. Repeat this ap-plication
in midsummer. Apply 25 to 30 lbs N per acre (3/4 lbs N/100 feet of row)
in April or May of the second year in a 4 foot wide band over the row.
Plantings 3 years old and older generally require 50 to 60 lbs N per
acre (1 1/2 lbs N/100 feet row) each year banded over the row. The variety
and soil type determine the exact amount of N required. Vigorous varieties
(Brandywine and Royalty purple raspberries, Eastern Thornless Blackberries
such as Chester and Hull, and primocane fruiting types such as Heritage)
usually re-quire 50 to 100 lbs more N. Plantings on light, sandy soils
require higher rates than those on heavier soils.
Generally, red raspberries should be fertilized to produce canes 5 feet
tall, and canes of purple raspberries should be taller than 5 feet. New
black raspberry canes should reach a height of 2.5 to 3 feet by harvest
time. Blackberry primocanes should be tipped at the appropri-ate height
(3.5 to 4 feet) and lateral branches should be well developed by the end
of the season.
(Source: Fruit Crop Advisory Team Alert, Vol. 16, No. 1, March 27, 2001)
A Prickley Subject-Brambles!
Suzi Teghtmeyer, University of Missouri
I noticed the other day I didn't have many websites about bramble crops
on my Fruit Links page http://library.smsu.edu/paulevans/frtlinks.htm.
While correcting this oversight I decided to share with you many of them,
primarily those Midwestern.
Brambles - Production Management and Marketing by Richard C. Funt et.
al, Ohio State University Extension Bulletin 782-99 http://ohioline.ag.ohio-state.edu/b782/index.html.
This is the premiere site I found on brambles. The address given is to
the table of contents, with the information divided into 6 chapters. Topics
covered include Selection and Care of Plants, In-sect and Mites, Integrated
Management of Bramble Diseases, and Marketing.
Fruit - Raspberries & Blackberries http://ohioline.ag.ohio-state.edu/lines/fcrop.html#FRU.6
The web address given compiles sites on the following subjects: Anthracnose
[of Raspberry and/or Blackberry], Spur Blight, Orange Rust, Botrytis Fruit
Rot "Gray Mold", Verticillium Wilt, Cane Blight, and Phytophthora
Root Rot.
Home Garden Raspberries and Blackberries Gerard Krewer et. al, Cooperative
Extension Service University of Georgia http://www.ces.uga.edu/pubcd/c766-w.html
A nice publication for the home grower.
Organic Culture of Bramble Fruits - A guide Pre-pared by Guy K. Ames,
George L. Kuepper, & Holly Born of ATTRA. http://www.attra.org/attra-pub/bramble.html
There isn't much in terms of organic bramble production on the web, but
this extensive publication (19 pages printed) is enough to get you started.
USDA Risk Management Agency Feasibility Studies- "Bramble Fruits:
An Economic Assessment of the Feasibility of Providing Multiple-Peril
Crop Insurance for Raspberries and Blackberries." http://www.rma.usda.gov/pilots/feasible.html
Small-Scale Fruit Production: A Comprehensive Guide http://ssfruit.cas.psu.edu/chapter7/chapter7a.htm,
a Penn State Cooperative Extension Publication. This is actually the full
chapter from this informative book. (Fun fact: the site defines different
bramble types including "Tayberries.")
Pruning Raspberries and Blackberries in Home Gardens by David W. Lockwood
http://www.utextension.utk.edu/spfiles/sp284g.pdf
Agricultural Extension Service, University of Tennessee An in-depth site
with many helpful illustrations of different pruning and trellising techniques.
Virus Diseases of Brambles in the Midwest http://www.ag.uiuc.edu/~vista/abstracts/avirus.html.
A 7-page document in .pdf format (click on the page image) from the Cooperative
Extension Service, University of Illinois.
As a final note, the Fruit Experiment Station also offers two publications
that are not online about growing blackberries and raspberries in Missouri.
For more in-formation contact Pamela Mayer, pam621t@smsu.edu.
(Source: The Berry Basket, Volume 4, No. 1, Spring 2001)
Blueberries
Mummyberry Disease in Blueberries
Sonia Schloemann, University of Massachusetts
For the past two years (1999 and 2000) Massachusetts has sought and obtained
a Section 18 Emergency Exemption for the use of Orbit® fungicide for
controlling the shoot blight phase of mummyberry in blueberries. Since
only 2 growers (3 acres) filed Use Reports for this material in 2000,
a Section 18 label was not pursued or obtained for 2001. However, a Section
24(c) Special Local Need (SLN) label has been sought for Bravo® fungicide
for this same use. The SLN label will also allow for the use of Bravo®
to control anthracnose. This SLN label will not be approved in time for
use against mummyberry this year. Growers should be pre-pared to use alternative
methods (e.g., raking beneath bushes to disturb germinating apothecia,
applying a 4" mulch layer over fallen mummies, or applying 200 lbs/acre
50% Urea prills to the soil surface beneath the bushes) for controlling
the shoot blight phase un-less/until the announcement for the use of Bravo
comes through. A bloom application of Captan 50WP/Benlate 50WP (at 5 lb/0.5
lb per acre, respectively) repeated at a 7 - 10 day interval is re-commended
for the bloom period to control the blossom blight phase of the disease.
This will also be an important spray for controlling Botrytis fruit rot,
which was a big problem last year. If we have a wet bloom period again
this year, growers should expect high pressure from Botrytis. Feel free
to contact me (43-545-4347) if you have questions.
Asana Insecticide for Blueberries
Celeste Welty, OSU Extension Entomologist
Registration for Asana XL (0.66 EC) has just been expanded to include
blueberries. Asana, a pyrethroid, controls cranberry fruitworm and aids
in control of cherry fruitworm at 4.8 to 9.6 oz/acre; it controls blueberry
maggot at 9.6 oz/A. The preharvest interval is 14 days. There is a limit
of 38.4 oz/acre per season. Asana can be applied before or after bloom,
but it acts as a bee repellent so should not be sprayed within 7 days
of pollination.
(Source: Ohio Fruit ICM News, Volume 5, No.14, April 27, 2001
Highbush Blueberry Fertilization
Gary Pavlis, Rutgers Cooperative Extension
Research conducted in the past 2 years in Michigan and New Jersey have
radically changed my thinking regarding the fertilization of highbush
blueberries. I summarized some of this work in my articles in this news-letter
last year however new findings this winter have resulted in further changes
in my recommendations. In the past, New Jersey blueberry growers would
have been advised to make their first fertilizer application around this
time. In fact, one blueberry grower told me that Good Friday was the traditional
day for the first application. Well, things have changed! Research out
of Michigan from Dr. Eric Hansen's lab, has shown that there must be leaf
emergence and growth before you have up-take of fertilizer by the blueberry
plant. So, if you are applying fertilizer now, you are wasting your money.
This is because only 10% of what you are putting on now will end up in
the plant. The correct timing for the first N-P-K application is during
bloom or shortly there-after. The second application should be made in
late June. So, timing is the first change we have made.
Secondly, after taking many leaf and soil samples this past year, and
I have realized one very important thing. Fertilizer recommendations which
are based on soil analysis are nearly worthless. Leaf and soil samples
which had been taken from the same plant never agreed, and the leaf analysis
shows what is actually getting into the plant. So, what do we do about
this? I believe the only important thing that we learn from soil analysis
is pH. Yes, pH is critical. Many growers have heard me say that the three
most important things you must know to grow blueberries is pH, pH, and
pH. This is especially true for growers who have plantings that are not
on soils that are naturally 4.5 to 4.8. The pH of the soil must be known
because leaf analysis results assumes that the pH is within the correct
range. If it is not within that range, I would not rely on the leaf analysis
recommendations.
So, what should growers do about fertilizing their blueberries? First,
every blueberry grower should have their blueberry soils tested for pH.
If soil pH is not within the 4.5-4.8 range, this should be adjusted immediately.
If the pH is higher, sulfur is added. If the pH is lower, lime is added.
The amount of sulfur or lime depends on your pH and I would have the pH
tested in the spring and fall until the proper range is attained. There-after,
fall pH tests are best because adjustments can be made then and the pH
will be correct by bud break in the spring. Second, this year's N-P-K
application should be made according to the timing above, but realize
that the amount, 600 lbs/Acre of 10-10-10 on a mature planting is largely
a guess until we take leaf samples in July. After that we can make recommendations
based upon the leaf analysis. Note: this can only happen if the soil pH
is correct or we must continue to guess on the recommendations. Lastly,
these changes are needed because even though the samples we took last
year were from growers who are some of the best blueberry growers in the
world, 70% of the plants were deficient in Nitrogen, and 97% were deficient
in one of the micro-nutrients. Nutrient deficiencies cause decreased yield,
lower fruit quality, in-creased disease problems and plant mortality.
We need to make these changes as soon as possible.
(Source: The Blueberry Bulletin, Vol. 17, No. 2, April 18, 2001)
Grapes
Grape mealybug - an insect to watch out for in Michigan vineyards
Rufus Isaacs and Keith Mason, Michigan State Univ.
During the 2000 grape harvest, consultants and inspectors in southern
Michigan reported some sooty black grapes and the associated pest insect.
This has been identified as the grape mealybug, Pseudococcus maritimus.
In an effort to help growers and crop scouts identify this insect, a description
is provided here.
Grape mealybug overwinters under loose bark or in crevices. As temperatures
increase in the spring, the yellow-brown "crawler" stage moves
to the clusters and developing foliage to feed. We expect this to happen
soon, as grapevines develop their early foliage.
The insect grows through a sedentary nymph stage and then becomes an
adult. Adult males are small with wings, while adult females are up to
3/16 inches long with waxy filaments around the body. This mid-summer
generation reproduces, creating a second generation that reaches maturity
late in the season.
Vines can tolerate the removal of sap by mealybugs, but their excrement
is the main cause of damage. This causes a blackening of grapes hanging
near the mealy-bugs because sooty mold fungus develops on their honeydew
secretions. Berries harvested with this damage, especially white varieties
where it is more apparent, are likely to be rejected for failing cosmetic
standards.
Mealybugs are naturally kept under control by lace-wings, ladybirds,
pirate bugs and spiders. These can at-tack mealybugs in hard-to-reach
places. Maintaining a pest management program that does not destroy your
biocontrol agents is the easiest way to avoid mealybug problems.
Chemical control works best when sprays are aimed at the mobile crawler
stage. When mealybugs are in the eggsac, or settle and are covered with
wax, it is harder for insecticides to reach them. Addition of oil to a
dormant spray has been recommended in California to increase penetration
of insecticides into cracks. Both Provado (1 oz/acre) and Guthion (2 lb/acre)
are registered for mealybug control in Michigan grapes. (Ed. Note: see
next article for information on materials registered in MA, RI, and CT
- SGS) Timing and coverage will be critical to effectiveness of any chemical-based
management.
We currently do not have much experience with mealybugs or with their
management in Michigan vine-yards. If you detect mealybug in your vineyard,
please contact your extension agent or call us at the MSU Small Fruit
Entomology Lab so we can arrange a visit: (517) 432-9554. We hope to learn
more about this pest during 2001.
For more information on grape mealybugs, try these websites:
http://www.msue.msu.edu/vanburen/fgmbug.htm
http://www.ipm.ucdavis.edu/PMG/r302301811.html
(Source: Fruit Crop Advisory Team Alert, Vol. 16, No. 3, April 24, 2001)
Editors Note on Grape Mealy Bug: Last season several vineyards in
Massachusetts and Rhode Island were found to have significant infestations
of grape mealy bug. This is a difficult insect to control because it re-sides
mainly within the multiple layers of bark of the vine's trunk. One indicator
of an infestation is the presence of unusual numbers of ants and/or the
presence of sooty mold on the vines, foliage or fruit. Both of these indicators
result from the presence of honeydew, which is excreted by the mealybugs.
A Section 2 (EE) supple-mental label for the use of Lorsban 2E as a dormant
trunk spray is being sought for Massachusetts, Rhode Island and Connecticut.
In addition, a Section 24(c) Special Local Needs label for Admire®
(Imadicloprid), a soil applied systemic insecticide, is being sought for
MA and RI. Clearance for these materials has not been confirmed yet, so
check with your state's Pesticide Registration Program or Extension Specialist
before using these materials. For a copy of the supplemental labels or
for help determining if you have a significant infestation of mealybug,
contact me at 413-545-4347.
Vegetation-free Area Surrounding Newly Planted 'Niagara' Grapevines
Affects Vine Growth
T. J. Zabadal and T. W. Dittmer, Michigan State Univ.
Abstract. Varying amounts of vegetation-free area (VFA) were established
around newly planted 'Niagara' (Vitis labrusca L. x Vitis vinifera L.)
grapevines to determine their influence on vine growth during the first
growing season. VFAs were either circular with radii from 0 to 5 ft (0
to 152 cm) in one experiment or in bands from 0 to 8 ft (0 to 244 cm)
in width in a second experiment. VFAs were maintained with biweekly manual
weeding for the entire growing season. Leaf, shoot and root dry weights
as well as the number of primary shoots and the length of the longest
root were measured at the end of their first growing season. The thresholds
for maximum vine dry weight biomass accumulation occurred with a circular
VFA of 4 ft (122 cm). When banded VFAs were used, total vine dry weight
biomass continued to increase up to the widest treatment of 8 ft (244
cm). Therefore, no threshold was attained. These are greater VFAs than
typically established around vines in commercial plantings. Therefore,
growers who desire to maximize vine growth of newly planted vines, should
consider larger VFAs around vines than has been traditional unless such
a practice is likely to cause surface soil erosion.
(Source: HortTechnology, Vol. 11, No. 1,Jan.-March 2001)
Grape Pest Management:
Alice Wise, Cornell Coop. Extension Long Island NY.
On April 26, Drs. Wayne Wilcox and Greg English-Loeb provided a tremendous
amount of food for thought in their discussion of the various aspects
of pest management. We all lose sight of the fact that at Cornell, we
have several of the most well respected grape research and extension specialists
in the country. Some interesting disease management points (insects next
week):
- Phomopsis cane and leaf spot pops up on shoots and rachises (cluster
stems), sometimes leaves and fruit. In many trials, Wilcox has found that
captan does provide a slight edge in control over mancozeb but not a significant
one. Phomopsis spores reside on the wood of the vine (trunks, canes, cordons-get
those old stubs pruned out) and apparently do not migrate far. If prunings
with phomopsis lesions are on the ground, these spores will not migrate
up into the vine. Spores are also not spread by pruning shears because
spores only germinate in rain. In a study on Concord grapes, Wilcox found
that two early sprays, applied before the immediate prebloom spray, provided
most of the control. When he waited until the immediate prebloom spray
to treat, there was virtually no control of the disease.
- Black rot affects both leaves and fruit. Fruit infections are probably
the number one home grapegrower disease problem. Wilcox has done extensive
work on the period of susceptibility of berries. In the vast majority
of seasons, berries are resistant to infection 4 weeks after bloom; in
some seasons, it may be as long as 6 weeks after bloom. Assuming bloom
is June 20, this means black rot is no longer a threat by early August.
The thing to keep in mind however is that as the season progresses, infections
take longer to show up. For example, if berries suddenly start to shrivel
in mid-August, it is probably from a black rot infection that occurred
in mid-July.
- Powdery mildew infection is a season long threat due to our temperate
climate. Powdery mildew severity is worse in higher humidities. In very
hot weather, disease pressure is lower because the fungus is inactivated.
Wilcox found a very significant correlation between the amount of disease
at the end of the season and the disease pressure in the vineyard the
next season. Serious powdery mildew on fruit mostly occurs bloom to several
weeks later. Berries don't completely lose susceptibility at veraison
but susceptibility is greatly reduced. If powdery mildew shows up, the
number one option for eradicating existing infections and protecting clean
foliage and fruit is JMS Stylet Oil (with good coverage). Applying sterol
inhibitors or strobilurins on existing infections is the recipe for creating
resistance.
- Downy mildew was a nightmare in some blocks last year. In wet years,
it's a battle; in dry years, it hardly shows up. Primary infections can
start as early as 2-3 weeks before bloom. It only takes 4-5 days after
infections for symptoms to appear so that scouting plays an important
role in controlling this disease. In wet years, downy does seem to appear
just before or around bloom. The good news is that after the first postbloom
spray, primary inoculum is pretty well shot and the need for additional
treatment is based on whether the disease is established in the vineyard
and weather. Not only rainy weather but also warm nights and dewy mornings
are ideal for downy development.
(Source: Long Island Fruit & Vegetable Update, No. 8, April 27, 2001
)
Pest Control News
Voluntary Cancellation of Benomyl (Benlate)
On April 19, we received news from DuPont and from the US EPA stating
that DuPont will discontinue the manufacture of its fungicide benomyl
and will phase out sales of Benlate in all its forms from the global market.
No sales will occur after December 31, 2001, and all product is expected
to clear channels of trade by the end of 2002. DuPont advised customers
that this is not a product recall, but a voluntary business decision based
on a review of global market conditions and other factors. The decision
is part of the recently announced re-structuring to improve the overall
competitiveness of its agricultural businesses.
DuPont's statement and the one from the US EPA carried slightly different
"spins." DuPont stated that "a significant element of the
reason to withdraw benomyl is that the company is no longer willing to
bear the high and continuing costs of defending the product in the U.S.
legal system where factors other than good science can influence outcomes.
In addition, there are significant on-going costs and resources necessary
to meet increased regulatory requirements around the world and keep the
product active. The company believes those resources are better applied
to other areas of the business." The EPA statement noted that the
EPA has been in the process of reviewing the human health and ecological
effects of benomyl in order to complete a reregistration eligibility decision
(RED) next year. The agency noted that the next step under FIFRA will
be for EPA to publish a Section 6(f) Federal Register notice announcing
receipt of the request for voluntary cancellation and inviting public
comment for 30 days.
DuPont noted that any question on the phase-out of benomyl may be addressed
to Richard A. Carver, Product Registration Manager, DuPont Crop Protection,
at 302-451-4517 or at his email address: Rich-ard.A.Carver@usa.dupont.com.
Select 2EC Registered for Use in Strawberries
A. Richard Bonanno, University of Massachusetts
Select (clethodim) has recently been registered under a supplemental label
for use in many vegetable crops and strawberries. Select is a postemergence
grass-only herbicide that is similar in chemistry to Poast (sethoxydim).
Both herbicides are very effective in controlling most summer annual
grasses. Poast, however, can be weak on cool season annual grasses as
well as perennial grasses. Growers who have had performance problems with
Poast, might want to try Select on these hard-to-control grasses. Research
has shown that Select may out per-form Poast on these grasses. The only
perennial grass listed on the label, however, is perennial bluegrass.
Application rates for annual grasses are 6 to 8 ounces/acre (0.1 to 0.125
lb a.i./acre). The application rate for perennial grasses is 8 ounces/acre
(0.125 lb a.i./acre). A repeat application after 14 days may be needed
for perennial grass control. Always use a crop oil concentrate at 1% by
volume (1 quart in 25 gallons of spray mix). The crop oil concentrate
enhances penetration into the grass foliage. Control of perennial grasses
will likely improve if ammonium sulfate is also added at a rate of 2.5¦to
4 lb/acre.
For strawberries, do not apply more than 8 ounces/acre per application.
Do not apply more than 32¦ounces/acre per year. Do not apply within
4 days of strawberry harvest.
Other crops listed on this supplemental label include tomato, pepper,
eggplant, sunflower, squash, pumpkin, cu-cumber, melon, potato, cranberry,
carrots, radish, and celery. Label directions are slightly different for
each crop. See the label for complete instructions.
Changes to Savey Label
Rick Foster, Purdue University
On April 18, 2001, the EPA approved the use of Savey 50DF for control
of mites on plums and prunes and on caneberries, including black and red
raspberries and blackberries. The preharvest restrictions are 28 days
for stone fruits and 3 days for caneberries. If you need a copy of the
supplemental label, either contact your Gowan distributor. (Ed. Note:
Savey was already approved for use in Strawberries for one application
only of 6 oz./acre with at 3 day phi.)
(Source:Facts for Fancy Fruit, April 25, 2001)
Food Poisoning Linked to Pesticide Sprays
"Research conducted by Dr. Greg Blank at the University of Manitoba
has revealed that bacteria commonly implicated in cases of food poisoning
(including Shigella, Salmonella, Listeria, and Escherichia coli O157:H7)
can "thrive" in solutions of some commercial pesticides (for
example, the insecticides permethrin and chlorpyrifos). The fear is that
use of bacteria-contaminated water in spraying rigs could result in enormous
increases in the concentrations of the bacteria during storage of the
pesticide solutions, resulting in greater potential for poisoning than
when contaminated water is used for irrigation. It seems to us that all
applications of bacteria-contaminated water to crops should be avoided,
although that isn't likely without regulatory prohibitions. In the meantime,
it makes good sense to be careful about the quality of water you use for
irrigation and for pesticide sprays applied to food plants.
Reference: Andy Coghlan, "Food Poisoning Bugs Thrive in Crop Sprays,"
New Scientist 168(2259), October 7, 2000: 20. (Source: HortIdeas, March
2001, 18(3): 27-28)
Getting the Most Out of Glyphosate and Other Sprays
Bruce Bordelon, Purdue University
Fruit growers often apply a post-emergent herbicide be-neath the tree
or vine row in spring to control winter annuals and other weeds. Often
a pre-emergent herbicide is included in this application. Glyphosate (Roundup)
is a post emergent systemic herbicide that is widely used for this first
weed spray. In order for glyphosate to be effective, it needs to be absorbed
into the plant. In soft water glyphosate has no problems in being absorbed.
However in hard water glyphosate will be 'tied up' and not absorbed as
readily. Hard water, common in many parts of Indiana, contains high concentrations
of soluble salts, calcium and magnesium. When these cations are present
they react with the negatively charged glyphosate to form compounds that
are not readily absorbed by plants. This results in poor uptake and poor
weed control. The solution to the hard water problem is to add ammonium
sulfate to the spray water before mixing with glyphosate. Ammonium sulfate
ions tie up the calcium and magnesium ions forming conjugate salts. Addition-ally,
some of the glyphosate reacts with ammonium to form a compound that some
weeds preferentially absorb. Follow the Roundup label recommendations
on the amount of ammonium sulfate to add. Another problem associated with
spray water quality is that many fungicides and insecticides break down
quickly in high pH water. Captan, Cygon, Imidan, Kelthane, malathion,
and Omite are examples of compounds that are especially vulnerable to
alkaline hydrolysis. Both the Commercial Tree Fruit and Small Fruit and
Grape Spray Guides have a discussion of spray tank pH. Briefly, addition
of about 2 ounces of food grade citric acid per 100 gallons of water will
lower the pH from about 8.0 to about 5.5. (Source: Facts for Fancy Fruit
2001-03, April 11, 2000)
That's a Berry Good Question!!!
Kathy Demchak, Penn State University
Q. Last month, you updated some information on conventional pesticides
for small fruits. Could you also cover information on some of the newer
pesticides, such as Oxidate, that could be used by organic growers? (paraphrased
from a conversation with Richard T., North Slope Farm, PA.)
A. Unfortunately, for many of these materials, there simply is little
information from studies published by sources other than the companies.
So, I must make it clear that I have little data on how well most of these
products work. If anyone would like to offer comments in that regard based
on their experiences, please send them to the address below. If you're
a certified organic grower, please check with your certifying agency before
use to make sure these materials are allowable. Only materials that have
come on the market for small fruits relatively recently are covered here.
I won't cover mate-rials that are strains of bacteria or fungi, as that
could take up the entire newsletter.
OxiDate (hydrogen dioxide, BioSafe Systems) is labeled for use on all
small fruit crops for control of Botrytis, downy mildew, fruit rot, leaf
blight and powdery mildew. According the label, it can be used both curatively
at a 1:100 dilution for 1 to 3 consecutive days, then on a 5 to 7 day
schedule after that. For preventative use, use a 1:100 dilution on a 5-day
schedule starting when the plants are small, then continue with a 1:300
dilution.
Armicarb 100 (potassium bicarbonate, Church & Dwight) is labeled
for use on all small fruit crops. The main benefit of this material seems
to be in the area of powdery mildew control, though the label lists a
number of other diseases. The rate is 2.5 to 5.0 lbs per acre, applied
at 1-2 week intervals. According to a company representative, attempting
to cut down on costs by cut-ting the rate will result in compromised control,
and the material should be reapplied if washed off. It works by contact,
so good coverage is a must.
Valero (cinnamaldehyde, Mycotech Corp.). This label was expanded to include
strawberries, raspberries, blackberries, blueberries and currants for
control spider mites and powdery mildew. It works by contact, so good
coverage is necessary. If the material dries too fast, control is negatively
affected, so the manufacturer recommends spraying early or late in the
day when humidity is higher, and also recommends spraying a small portion
of the planting first to check for phytotoxicity.
Surround (kaolin, Engelhard Corp.) is for processing brambles and blueberries
for use as a repellent and protectant against Japanese beetles, leafhoppers,
and thrips. The rate is 12.5 to 50 lb/acre at 7-21 day intervals (de-pending
on crop growth rate), starting after fruit set.
Neemix (azadirachtin, Thermo Trilogy) is labeled for all small fruit
crops for control of whiteflies, aphids, leafminers, leafhoppers, and
leafrollers. Rates and timing intervals vary with the insect. It interferes
with molting, and therefore kills the larval stages only. It also can
repel and deter the adults from feeding, but in some cases this effect
was temporary.
Trilogy (neem oil extract, Thermo Trilogy) contains a number of compounds
with some activity against a ranges of insects, mites, and diseases. It
is best used be-fore outbreaks occur. Rates vary with the target.
Messenger (harpin protein, Eden Bioscience) binds with the plant leaf
surface, making it behave as though it is under attack by a disease, thereby
triggering its defenses and affecting other physiological processes as
well. It is labeled for use on all small fruit crops at rates of 2.25-13.35
oz/acre.
(Editor's Note: Check with your state's Pesticide Registration Office
to be sure that these materials are registered for use in your state before
using them.)
(Source: THE VEGETABLE AND SMALL FRUIT GA-ZETTE, April, 2001, Volume 5,
No. 4)
General
New Farmers Market Book
Vern Grubinger, University of Vermont Extension
The New Farmers' Market: Farm-Fresh Ideas for Producers, Managers and
Communities is a 272 book that covers the latest tips and trends from
leading-edge sellers, managers and market planners all over the country.
Part I (Selling at the Market), talks about best products to grow and
sell at the markets, how to combine farmers' markets with other outlets,
record-keeping, display, merchandising and much, much more. Part II (Starting,
Managing and Promoting the Market) talks about every aspect imaginable
of starting, managing and promoting the market: location, attracting vendors,
rules and regulations, insurance, "farmer-grown," advertising,
special events, establishing a market web site, and more. Part III (The
New Farmers' Market) talks about educating the community about the value
of fresh, local foods and farmers' markets and about how farmers' markets
can serve the community. Appendices cover insurance, customer surveys,
farmers' market profitability, and benefits of farmers' markets. A seven-page
list of Re-sources is valuable for locating scales, baskets, packaging
materials and more. To order, send $24.95 plus $4.50 (Canada: $8.40 US)
shipping to: "QP Distribution", 22260 "C" St., Winfield,
KS 67156. Credit card orders call 888-281-5170.
(Source: VERMONT VEGETABLE AND BERRY NEWS - May 1, 2001)
Get Cholinesterase Blood Test Now - before you spray
Howard J. Doss, Michigan State Univ.
Farmers and others working with organophosphates (OP) and carbamate pesticides
should get a baseline cholinesterase blood test now before handling pesticides.
With this test a physician can determine if a summertime illness is the
result of exposure to pesticides. It is important that the test be taken
before handling pesticides to ensure that cholinesterase levels will not
be affected by a recent exposure to these chemicals.
What is cholinesterase?
Cholinesterase is an enzyme that is needed for the human body's nervous
system to function properly. Vertebrates (including humans) and insects
have this same type of enzyme. Pesticides in the organophosphate and carbamate
chemical classes are cholinesterase inhibitors, which makes them effective
in controlling in-sects and some vertebrate pests. Unfortunately, when
people breathe in these pesticides or get them on their skin, they are
subjected to the same poisoning effect. Whether or not you get sick depends
on how much and how often you are exposed.
What is the function of cholinesterase in the body? The nervous system
of mammals (including humans) and insects uses electrical signals traveling
along nerve cells to carry messages from one part of the body to another.
Between nerve cells, there are gaps. To get across the gap, animals change
the electrical signal into a chemical signal. The chemical moves across
the gap, signaling the next nerve to begin electrical firing. One of these
chemicals found in the nervous system of both mammals and insects is acetylcholine.
Once the acetyl-choline reaches the next nerve, an enzyme called acetyl-cholinesterase
breaks down the remaining chemical, "cleaning" the gap and readying
it for the next nerve signal. Organophosphates and carbamates disrupt
acetyl-cholinesterase, causing a build up of acetylcholine in the gap
and, thus, continuous firing of the nerves.
Symptoms of mild OP and carbamate exposure include headache, dizziness,
nausea, and restlessness. Higher exposure can cause mental confusion,
shortness of breath, constricted pupils, and even coma or death.
Why should you have a cholinesterase test now? For the typical Michigan
farmer, all pesticide application equipment has been stored for several
months, an indication that the farmer has not been exposed to any pesticides
since it was last used. This break from handling pesticides gives the
body time to renew any cholinesterase destroyed by previous exposures
to organophosphates or carbamates.
During this absence from pesticides, the body's cholinesterase levels
return to normal, so a medical physician can determine a baseline level
through a blood test. This summer, if you develop symptoms of exposure
to an organophosphate or carbamate pesticide, your physician can compare
your current cholinesterase levels with baseline levels taken before the
spraying season begins with the cholinesterase inhibitor chemicals.
Cholinesterase levels vary between people. There-fore, you need to have
your own baseline value to determine what is normal for you. According
to Kenneth Rosenman1, MD, a Board Certified Internal and Occupational
Environmental Medicine specialist for Michigan State University, a baseline
reading before the field season and then periodic testing of cholinesterase
on the same day after you spray throughout the spray season is useful
to determine if your work practices and protective equipment are adequate.
Rosenman points out that a 20 percent decrease of cholinesterase from
baseline levels is an indication that a farmer must review his or her
work practices to minimize any potential health effects. Symptoms typically
don't occur until cholinesterase levels decrease 50 percent from baseline,
with severe poisoning occurring at a 90 percent decrease. At a 50 percent
decrease from the baseline the applicator or handler should be removed
from jobs involving these pesticides until cholinesterase levels recover.
References: 1 Kenneth Rosenman, M.D., College of Human Medicine, Oc-cupational
& Environmental Medicine 1-800-446-7805.
(Source: Fruit Crop Advisory Team Alert, Vol. 16, No. 1, March 27, 2001)
Grower Questions
Q: My employee has been pruning my blueberries for years. Last year
and this year she has discovered weak branches that when cut off reveal
a hollow stem as made by a boring insect. The hole is about 1/16 th of an
inch in diameter and there are a couple of side holes that look a little
smaller. Liz has found a worm inside which she describes as "shiny
black head, milky grey soft body".
We have a pretty thick layer of woodchips around each plant. We have drip
irrigation which isn't run as often as it should be. There are several varieties
in the 1/2 acre planting including Blueray, Herbert, and Coville, though
I can't tell you now which variety the sample came from. I'm hoping that
you might know what the insect is and what I should do about it. Your response
will be most appreciated.
A: This sounds like Blueberry Stem Borer. I'll tell you what the NRAES Blueberry
Production Guide says about them:
"Description and History: The adult blueberry stem borer is a thin,
parallel-sided beetle with long antennae, about 1/2 to 5/8 inch long.
The adult girdles small stems near the tip and lays and egg under the
bark during late June or July. A fleshy, legless grub hatches from the
egg and begins to tunnel in the stem. During its 3-year development, the
larva tunnels down the stem, and continues in a cane, often coming back
up another cane after reaching the crown in the third year. It bores small
holes to the outside of the cane through which it expels its sawdust-like
frass. It pupates inside the larval tunnel.
Damage and Importance: Tunneling in canes reduces vigor and severely
weakens the structure of the plant. This insect is not a frequent pest
in well-pruned fields.
Monitoring and Control: Weak growth, flimsy canes, and holes emitting
sawdust make this insect easy to detect. Pruning out infested canes provides
adequate control; few infested canes will remain after normal pruning."
Pesticide applications are very unlikely to help with this pest since
it spends most of its time protected within the canes. My suggestion is
to be sure to prune out all infested stems. Keep cutting until you get
below the tunnel. Check closely for the pinholes to determine which stems
are infested. Burn the prunings.
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