Title: Blueberry news
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Permanent Link: http://ufdc.ufl.edu/UF00089445/00008
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Title: Blueberry news
Series Title: Blueberry news
Physical Description: Serial
Creator: Florida Blueberry Growers' Association
Publisher: Florida Blueberry Growers' Association
Publication Date: Spring 2002
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Bibliographic ID: UF00089445
Volume ID: VID00008
Source Institution: University of Florida
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Official Newsletter of the Florida Blueberry Growers

The Blueberry News
Official Newsletter of the Florida Blueberry Growers' Association
Spring Issue, 2002 (Print Version)

Editor: Jeff Williamson (Professor, Horticultural Science Department, IFAS, University of Florida)

Officers: Jerry Mixon, Jr. (president), Dean Deihl (vice president), Sheri Brothers (secretary and treasurer), Jeff
Williamson (educational program director and newsletter editor).

Board of Directors: Jerry Mixon, Jr., Dean Deihl, Ken Patterson, Jimmy Miller, Gerald Mixon, Bob Payne, Steve Blount
and Paul Lyrene.

Disclaimer: The information in this newsletter was selected with good intentions by the editor. It does not necessarily reflect the opinions of the
editor, the Florida Blueberry Growers' Association or the Association Directors. The reader should not assume that the information presented in
the newsletter is being recommended for his or her farm. Especially where pesticides or growth regulators are mentioned, be sure to follow their
labels exactly. If you have comments, corrections, or suggestions regarding the newsletter, please write to the editor

Spring Blueberry Field Day
IGAP Blueberry Farm
Thursday, March 7, 2002

9:00 a.m. Registration (pre-registration required for lunch).

9:30 a.m. Opening remarks Mr. Jerry Mixon, FBGA president and grower, Haines City, Fla.

9:45 a.m. Comments on blueberry pollination Dr. Kenna MacKenzie, entomologist, Atlantic Food and Horticulture
Research Centre of Agriculture and Agri-Food Canada in Kentville, Nova Scotia

10:15 a.m. Observations on Dormex in 2002 Dr. Jeff Williamson, extension horticulturist, Horticultural Sciences
Dept., University of Florida, Gainesville.

10:35 a.m. Observations on thrips and gall midges in 2002 Dr. Paul Lyrene, blueberry breeder, Horticultural
Sciences Dept., University of Florida, Gainesville.

11:00 a.m. General discussion

11:15 a.m. Preview of field tours Mr. Ken Patterson, blueberry grower, IGAP, Hawthorne, Fla.

11:30 a.m. Lunch Pre-registration required

12:30 p.m. Visit blueberry fields

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The Blueberry News

Official Newsletter of the Florida Blueberry Growers

Directions to the field Day IGAP Blueberry Farm is not far from Hwy 301. If traveling from the south, continue north on
Hwy 301 until about 4 miles north of Citra. If traveling from the north, continue south on Hwy 301 until about 6 miles south
of Hawthorne. Turn east on 177 Ave. Continue to the end of the road and turn left; go about 100 yards and turn right. You
will still be on 177 Ave. Go to the end of the road and turn right onto 243rd St. Go to the end of the road and turn left on
193rd Ave. Continue to the end of this road and you will be at IGAP Farm 3 and the nursery. This will be the meeting place
for the field day.

A Message from the President

I hope you didn't blink-winter has come, and it appears to be gone. Most areas report sufficient chill hours to induce
good vegetative and fruit bud break. In fact, by now most of you are probably seeing some of both in your fields. Keep alert
to flower thrips and even the beginning of gall midge. It is about time to bring in bees if you have not already done so.
Make sure your hives are vibrant with no roaches or frames that are in poor shape. With as many flowers as our fields can
produce, we need every bee we can get. As great as the warm weather is, be on guard for a February cold snap. It would
be an unusual late winter/early spring if we did not have at least a couple of nights (or as in the case of 1994, 10 to12
nights) where we have to diligently watch weather conditions.

We have a great field day planned at Island Grove Ag Products Farm in Hawthorne. We are planning on a couple of very
timely talks a discussion on gall midge and thrips, and hopefully we will get to meet our new small fruit entomologist Dr.
Oscar Lieburd. We will also get to tour a new planting so those new to the industry will get to see the elements involved in
planting blueberries.

It also looks like we have a label on Spintor insecticide, which will prove valuable in our battle against thrips during the
bloom period. As well, Jeff is working with the Florida Fruit and Vegetable Association on a Section 18, (emergency use)
label for Indar fungicide for control of rust and septoria leaf spots.

As you can see there are a lot of things going on. I look forward to seeing you at the Spring Field Day.

Jerry Mixon, Jr
Mixon Family Farm and FBGA President

Spintor Approved for Use on Blueberries in Florida

By Jeff Williamson

On January 25, 2002, I was informed that a supplemental label for use of Spintor 2SC to control thrips has been accepted
by the Florida Department of Agriculture and Consumer Services. Growers who wish to use this product must have a copy
of the supplemental label in their possession.

An advantage of Spintor over other insecticides that are currently labeled for thrips control in Florida blueberries is that, if
properly applied, Spintor can provide control of thrips during the bloom period. However, Spintor 2SC is toxic to bees.
Therefore, care must be taken not to apply this product when bees are in the field actively foraging. More information on
this use restriction can be found in the Environmental Hazards section of the main label affixed to the container. You may
also view the supplemental label and the main label for Spintor 2SC at the following web site www.hos.ufl.edu (click on
"news", then click on "spintor re-approved").

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The Blueberry News

Official Newsletter of the Florida Blueberry Growers

Paul Lyrene has prepared an excellent article for this newsletter which you should find helpful when making
determinations about the potential threats posed by thrips and blueberry gall midges.

Visiting Scientist

Dr. Kenna MacKenzie, the berry crops entomologist at the Atlantic Food and Horticulture Research Centre of Agriculture
and Agri-Food Canada in Kentville, Nova Scotia, is spending six months in Florida. Lowbush blueberry pollination forms
the backbone of her research program in Nova Scotia. She also works on pollination of other fruit crops including
cranberry and apple, and pest management issues in many berry crops. She is an expert in Vaccinium pollination having
worked on three important North American crops, cranberry, lowbush blueberry and northern highbush blueberry. While in
Florida, Kenna is planning to work on pollination problems in southern blueberries as well as thrips management in
collaboration with Dr. Paul Lyrene and Dr. Oscar Liburd. She is working out of Dr. Lyrene's lab in the Horticultural
Sciences Department at the University of Florida.

Gall Midges and Thrips in Florida Blueberries

By Paul Lyrene.

Gall midges (Dasineura oxycoccana) are tiny flies that pass 6 to 10 generations per year on blueberries in Florida The
adult flies live only a few days. Even if gall midges decimate your crop, you may not ever notice them unless you know
when and how to look for them. The female flies lay eggs into expanding blueberry flower buds and tender new vegetative
growth, just as the bud scales are separating. Within a week, the developing flower buds or shoots are dead. The soft new
tissues have been dissolved by enzymes from the developing midge larvae. The larvae are tiny, white-to-orange maggots,
almost too small to see without magnification. After a few days, the larvae become pupae, which are small and orange,
and after a few more days adult flies emerge. Gall midges overwinter as larvae or pupae in the soil beneath the bushes. In
Gainesville, a week or two of warm weather in January, February, or March can cause flies to emerge from the soil, and if
there are flower buds at susceptible stages on susceptible varieties, many of the flower buds may be killed before the
flowers appear. Highly-susceptible rabbiteye varieties such as Windy and Premier are at great risk if gall midges are flying
as the flower buds begin to swell, and Aliceblue, Beckyblue, Climax, and Bonita are only slightly more resistant. Killed
flower buds stop development. The damage later looks like freeze injury. In times past, much gall midge damage to the
flower buds was blamed on freezes.

Blueberry gall midges only attack blueberries, cranberries, and their close relatives. Numerous other types of gall midges
attack other plants, but each is confined to its own host species. Most gall midge damage I have seen on blueberry flower
buds in Florida has been on susceptible rabbiteye varieties, not highbush. Rabbiteye varieties whose flower buds seem
quite resistant to gall midges include Brightwell and Powderblue. The flower buds of most southern highbush varieties
seem rather resistant to gall midge damage, but I wouldn't totally discount midges as a threat to southern highbush flower

The main problem from gall midges on southern highbush blueberries comes from their ability to prevent normal leafing of
the plant in the spring. This is a serious problem in Florida, in view of the great importance of early leafing to early-ripening
blueberries. Almost all the sugar needed to produce large, sweet blueberries is made in the leaves during the 60 days
(more or less) between flowering and ripening. Sparse leafing during this period can make the berries smaller, insipid,
prone to green or pink undersides, and later ripening. Not all poor leafing problems can be blamed on gall midges some
varieites leaf poorly even without midges, but midges are serious enough to demand daily scouting in the blueberry field
during spring leafing. What are the indications that gall midges have been damaging blueberry leaf buds? Normally, within

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The Blueberry News

Official Newsletter of the Florida Blueberry Growers

a month after the plants start growing in the spring, the strongest new shoots should be 8 to 12 inches long, each shoot
with 6 to 8 large, well-formed leaves. If, instead, the plant is full of short, weak, shoots, each bearing only a few twisted,
misshapen leaves, and if new growth on the plant seems thin and sparse, gall midges may be the culprits.

When the blueberry plants are first sprouting in the spring the new leafy shoots emerging from the buds look like small
green flames from tiny candles. These new shoots are in great danger from gall midge attack. And always, at the tip of a
growing shoot, is a tiny furl of soft tissues that can feed gall midge larvae. If midges lay eggs in the soft new tissues, the
tips will die within a few days, and a weak, short branch will be produced in place of the long, vigorous shoot that should
have been. The shoots will have only one to three small, twisted leaves and a tiny black tip where the midges killed the
growing point. Blueberry plants have lots of leaf buds. A few weeks after the first buds are killed by midges, a second
group will try to grow. If some force of nature or some action by the grower has reduced the gall midge population in the
field, these second shoots may succeed where the first failed, giving you the growth you should have had some weeks
earlier. Unfortunately from late February through early April in Florida, gall midges tend not to vanish if they were abundant
earlier. The midges stop flying during cold periods in the spring, but when it is cold enough to stop the midges, blueberry
shoots will cease to grow. When it warms up enough for the resumption of shoot growth, the midges will become active
again. Natural selection has adjusted the midges' life cycle so that they emerge to lay their eggs when there is something
for the larvae to eat, namely soft, new blueberry tissue.

Blair Sampson, USDA Small Fruit Research Station, Poplarville, Mississippi has found that blueberry gall midges are
often heavily parasitized during the summer by tiny wasps that lays eggs in the larvae, killing them before they become
adults. Once these wasp populations build during the summer, gall midges can almost vanish from the field, and the
blueberry plants can usually produce new growth flushes through the summer without major interference from gall midges.
However, in our blueberry breeding greenhouses in Gainesville, where small rooted cuttings are flushing through the
summer, gall midges, if not controlled, can kill almost every shoot tip through the summer and fall. The parasitic wasps
seem unable to establish in our greenhouses. Meanwhile, rooted cuttings just outside the greenhouse in August and
September sometimes grow well without visible gall midge damage.

Next, I will discuss thrips. Thrips are small, active insects with rasping mouthparts. Although they are a lot larger and
more conspicuous than gall midges, they still are not much more than a quarter of an inch long. They are yellowish in
color and shaped like a cigar. They commonly can be found running around inside open blueberry flowers, but they can
also fly. I have seen times when the air in fields around Gainesville seemed to be full of them. I have also seen times
during blueberry bloom when a car parked beside a blueberry field quickly became covered with hundreds of thousands of
alighting thrips. At such times, it is possible to hold a white paper under a cluster of blueberry flowers, shake the cluster
over the paper, and dislodge 10 or 20 thrips, which then run across the paper looking for a place to hide.

Unlike gall midges, thrips have a wide host range, feeding on the flowers of many species of plants. They have been
shown to cause poor fruit set on lime trees in Florida. Jerry Vanerwegen reports that thrips are abundant when titi trees
are blooming in the swamps of Clinch County Georgia. The flowering heads of Rumex hastatula, called Florida buckwheat
or sour sorrel, a red-stemmed weed that is abundant in fields and pastures in north Florida in winter, are often loaded with
thrips just before the blueberry flowers get to the vulnerable stage. If abundant in the field when the blueberries flower,
thrips can greatly reduce fruit set. Most commonly, this results from thrips damage to the stigma and style. As soon as a
flower opens far enough for the slender body of a thrips to enter, the thrips starts rasping away on the style and stigma.
After a short time of feeding, pollen tubes can no longer grow down the damaged style to the blueberry ovules. The result
is no seeds and no ripe fruit. It may just be one of my superstitions, but it also seems to me that bees are less active in
blueberry fields that have a lot of thrips. The normal time to notice a problem from earlier thrips damage is 2 to 4 weeks
after the flowers were damaged, when the small green berries, which failed to develop after the petals dropped, start
raining onto the ground. Years ago, many of us blamed this fruit drop on poor pollination (which was not entirely wrong),
and tried to rescue the crop by spraying gibberellic acid. GA sprays helped rescue some crop but seldom gave really
great crops.

If thrips are abundant during blueberry flowering, they can ruin the blueberry flowers even before they open. They do this
by maneuvering themselves to the inside of the clusters of still-unopened flowers and feeding on the outsides of the

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The Blueberry News

Official Newsletter of the Florida Blueberry Growers

corollas and on the stems that attach the flowers to the cluster. This kind of damage can cause the flowers to wilt and
can keep them from ever opening. In some bad thrips years, thrips can even cause soft spots on southern highbush
berries when they begin to ripen. With their great propensity to stay inside of some crack or crevice the thrips will crawl
around on the cluster of ripening berries, concentrating their rasping at the points where two ripe berries are touching.
There, their feeding will make a soft spot on both berries, just at the point where the berries were touching. Thrips seem to
prefer flowers above all other plant tissues. They don't seem to prefer berries. But sometimes as the last of the blueberry
flowers are fading, after thrips populations have built up to very high levels in the blueberry field during flowering, they go to
the berries because there is no other convenient food. Soon after the last of the flowers are gone, damage to the berries

Thrips have a short generation time. In Florida, where blueberry flowering is often prolonged, they can greatly increase in
number during the flowering season. I remember many years back in the 1980s and early 1990s when late freezes would
kill the earliest-opening flowers of the rabbiteye varieties, leaving the later flowers seemingly undamaged. However, these
later flowers would often set little or no fruit, seeming to develop brown streaks in the corolla and to dry up without
opening. I am now convinced that thrips and gall midges, not hot weather or lack of bees, were the culprits.

Can thrips interfere with early leafing in blueberries in Florida? Yes, if they are abundant when the new shoots are starting
to grow. If present during first leafing, thrips can poke their way into the tender, unfurling leaf clusters. Although not as
devastating in this regard as gall midges, thrips can damage the young tissues and cause the new leaves to be
malformed, sometimes with blackened tips. To learn more about thrips and gall midges, try a GOOGLE search on the
web. If you choose the Google advanced search option, where it will bring only articles that contain all the words you put
in the search box, the entry : "Dasineura oxycoccana" will get plenty to read about gall midges and "blueberry thrips" will
keep you busy reading about thrips. Not to roam too far from the subject, but Google searching on the internet, in my
opinion, makes most other ways of acquiring information obsolete. Recently I was trying to find out about Cylindrocladium
stem rot in blueberry cuttings, and using Google for one hour, I found out more than I could have found out in a week of
telephoning and library searching.

I don't have space here to give specific advice on controlling blueberry gall midges and thrips in your blueberry production
fields, nor am

I qualified to do this. There are other sources for this information. I would, however, give this general advice. First, learn
how to recognize the damage of these two insects. You have to watch your fields day by day during the periods thrips and
gall midges could be getting established. If you wait until the damage is obvious, it may be too late. Second, learn which
developmental stages of the blueberry plant must be protected from these insects. There is no reason to spray for gall
midges during the summer when parasitic wasps are operating and the plants are already fully clothed with new leaves.
There is not much danger from thrips if no flowers or advanced-stage flower buds are present in the field. However, you
must protect the flower buds of susceptible rabbiteye varieties from gall midges while the buds are swelling, and you must
protect the new growth flushes of both rabbiteye and highbush in the early spring from both thrips and gall midges. In
addition, in both highbush and rabbiteyes, you must keep thrips populations low in your fields during flowering and
immediately before and after flowering.


Blueberry Hill Nursery. Come by and see our plants, potted rabbiteye and highbush. We're in Salt Springs. Call
(352)685-2769 or (352)622-9190. Lic. No. 47217069.

Call the Doc! Doc Applications, Inc. is booking orders for the fall 2000 and beyond. We grow the latest varieties including
Gulfcoast, Sharpblue, Sapphire, and Emerald bare root and in containers. Call Dave Weber (863)325-8215 for price and
availability. Lic. no. 47219637.

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The Blueberry News

Official Newsletter of the Florida Blueberry Growers

Elixson Wood Products, Inc. Pine bark shredded, nuggets, or fines available. Ph (904) 964-6649.

Island Grove Ag. Products. Don't buy plants until you've talked to us. We have all varieties including the new highbush
releases from U of F. We will grow specifically for your needs. Call John Purcell or Ken Patterson at (352)481-5558. Lic.
no. 47217870.

Miller Blueberry Nursery. Rt. 3, Box 5700, Palatka, FL 32177, Telephone (904) 325-7373. Let us supply your blueberry
plants. All varieties. All sizes. Bare root and potted. Please call for prices. Lic. no. 04720531.

Mixon Family Farm, Inc. We have excellent quality blueberry plants for sale. We have Misty as well as all the newest
releases from the University of Florida including Sapphire, Jewel, Star and Sante Fe. We will custom grow for your
specific needs. Call Jerry Mixon (863)439-8335 for price and availability. License no. 472255191

My Blue Heaven Blueberry Nursery. Southern highbush varieties. Centrally located in Dade City. Give us a call, we're
happy to help. Debra Troyer (352) 567-4256, 18414 Lawrence Rd., Dade City, FL 33523. Lic. no. 47221916.

Southern Highbush Blueberry plants for-sale Several varieties. Call for prices and availability. Bob Waldo, Hudson, FL,
(727) 863-4214. Lic. no. 47227344.

Strickland Blueberry Farms and Nursery. 4956 Slaten Rd., Plant City, FL 33567 Phone (813) 754-3866. FAX:
(813)754-8717. 'Gulfcoast' and 'Sharpblue' in 1, 15 and 25 gal. containers. Large quantities available. Come see an
alternative planting method. Lic. no. 47220729.


We welcome advertising from blueberry nurseries and suppliers. The cost is 30 cents per word per issue of the newsletter
in which your message appears. Send your blueberry-related message and a check payable to FLORIDA BLUEBERRY
GROWERS' ASSOCIATION to our address given below under membership information.


To join or renew your membership to the Florida Blueberry Growers Association, mail a check payable to FLORIDA

Florida Blueberry Growers' Association

P.O. Box 141733

Gainesville, FL 32614

The Association annual dues depend on which membership category you fit best.

1. Regular Florida Member $10.00 per acre of blueberries, except a minimum of $50.00 and a maximum of $200.00.

2. Out-of-state member $50.00

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The Blueberry News

The Blueberry News Official Newsletter of the Florida Blueberry Growers

3. Associate member $100.00 (Equipment and chemical companies, etc.)

4. Educational and Research $10.00 (University and USDA personnel who do not grow blueberries commercially)

Related Links:

University of Florida
Institute of Food and Agricultural Sciences
Horticultural Sciences Department
Florida Cooperative Extension Service
Jeff Williamson

This page is maintained by Susie Futch zsf@mail.ifas.ufl.edu.

Page 7

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