Facts for Fancy Fruit 99-05 May 5, 1999

Crop Conditions:  Warm sunny weather across the state over the past
several days has increased plant development considerably. It looks
like weÕre about one week ahead of normal on most crops. Apples are
just past petal fall in southern areas of the state, while full bloom
is underway in more northern areas. Peaches are at shuck split in the
south, but itÕs hard to assess the stage of growth in central and
northern areas (there are no peaches!). Early grape cultivars have 3 to
6 inch shoots in southern areas and 1-2 inch shoots north. Raspberries
and blackberries should bloom soon in the south. Blueberries are at
bloom in the north central region.

Weather Update:  La Nina and Omega BlocksÉ.. thereÕs more to weather
than you may want to know. We are still experiencing the effects of a
mild La Nina and can expect big temperature shifts to continue
according to Tom Priddy, University of Kentucky Climatologist.
However, the recent string of warm sunny days was due to an Omega block
which occurs when troughs of low pressure in the upper atmosphere
develop over the east and west coasts and high pressure ridging settles
over the central U.S. Warm, dry arm surges northward through the
central U.S. An Omega block is very stable and once established can
last for several days. The 6 to 10 day forecast calls for normal
temperature and above normal precipitation. The outlook for May calls
for normal temperature and above normal precipitation, and the long
range forecast for May-July calls for normal temperature and above
normal precipitation.

Extension Director Search at Purdue University:  As many of you may
know, Dr. Hank Wadsworth, Director of Cooperative Extension Service at
Purdue, has announced he will retire in June this year. The search for
a new director is actively underway and four very good candidates have
interviewed. Dean Lechtenberg should have something to announce in a
few weeks.

State Budget Includes Funding for Purdue Cooperative Extension Service:
The State Legislature passed a budget that included $2.8M support for
the Cooperative Extension Service for each year of the biennium. That
is great news for CES. It will become part of the base for future
biennia and it will allow CES to immediately recruit positions that
have been held vacant for the last year. Director Hank Wadsworth
extends his thanks to all of you for your help in supporting this
important legislation. We know that many of you talked to your
Legislators about it and we want to thank you for your efforts. We also
urge you to make sure the members of the Legislature are appropriately
thanked. Please express our appreciation to your Representative and
Senator.

Apple Scab:  As I look out the window and see the rain coming down,
with the temperature at 65¡ F, my reflections go to apple scab.  At
these temperatures it will take only 9 hours for a light infection or
18 hours for a heavy infection; and to make you feel even better, the
new scab infection tables indicate infection can take place in as
little as 6 hours at 65¡ F.  In addition, the period when the number of
ascospores reach their peak is generally pink through bloom.  Hopefully
all growers are covered with a good protectant or plan to spray at the
first opportunity with Nova, Rubigan or Procure. -Pecknold

Nova, Procure & Rubigan Resistance:  Speaking of Nova, Rubigan and
Procure. At a recent meeting a number of commercial apple growers
indicated they have been using sterol inhibiting (SI) fungicides (Nova,
Procure and Rubigan) for 6 yearsÉ or more.  DonÕt panic, butÉ research
out of Geneva, New York, indicates that in orchards where SI fungicides
have been used for 7 to 8 years there is a significant increase in the
potential for strains of the scab fungus resistant to SI fungicides to
be present.  The researchers, Drs. Koller and Wilcox, ask the question:
 ÒWhere do we stand right now on SI resistance to registered SI
fungicides in New York apple orchards?Ó  Their answer is as follows:

* SI resistance has increased in New York over the past 10 years, but
in most orchards, resistance remains at a low and manageable level.  In
the vast majority of commercial orchards, SIs will remain effective if
they are used carefully according to the Òrules.Ó

* The first rule.  Use full rates of the SI.  Do not ÒcheatÓ on the
rate, the coverage, or the spray intervals.  Alternate row-middle
spraying may spell disaster with the SIs.  Using full rates is even
more important with continued use and as the scab fungus becomes less
sensitive.

* The second rule: Mix the SIs with a protectant.

* The third rule:  Do not use SIs in a ÒdelayedÓ program ( i.e. the
four spray program as described on page 11 of ID-168, Ò1999 Indiana
Commercial Tree Fruit Spray GuideÓ).  This program was developed under
ÒbaselineÓ conditions and used one of the very potent SI fungicides
(Nustar).  Earlier, yet timely, spraying has once again become more
important because many of our New York orchards are not at ÒbaselineÓ
sensitivities.  In addition, there will be very few Òlow inoculumÓ
orchards in 1999 after the difficult scab year of 1998.

Again, donÕt panic, the results of the above research are even Òkind of
goodÓ.  The researchers did not find wide spread occurrence of high
levels of SI resistance.  However, they do make the point that
judicious use of SI fungicides is becoming even more important the
longer we continue to use them. -Pecknold

Peach Scab:  Just in case there are growers out there with
peachesÉ..early shuck-split and shuck-fall sprays are critical for
peach scab control. The first spray should be applied about one week
after petal fall.  Do not wait until the shucks have slipped to begin
this program. Continue to spray on a 10 day interval until 40 days
before harvest. See  ID-168, Ò1999 Indiana Commercial Tree Fruit Spray
GuideÓ, for further information.  -Pecknold

Early Season Grape Disease Control:  The most important time of the
season for disease control in grapes during the early growth stages,
from early shoot growth through two weeks post bloom. The major
diseases of concern are black rot, Phomopsis cane and leaf spot, downy
mildew, and powdery mildew. These pathogens overwinter on grapevines
and vineyard debris and become active during this time. Spores produced
from these overwintering structures are the Ôprimary inoculumÕ for the
new season. If these primary spores cause infections on the new growth,
secondary spores can be produced throughout the growing season, causing
a high level of disease pressure whenever environmental conditions are
conducive. When vines are protected from primary infections by a good
spray program during the early season, or if weather conditions are
unfavorable for infection, the overwintering inoculum will be expended,
no secondary spores will be produced, and there will be much less
disease pressure during the remainder of the season.  The basic rule
is: It is much easier to prevent a disease outbreak than to stop one in
progress.
	There are many factors to consider when deciding on a spray strategy,
including weather conditions, disease history of the vineyard, varietal
susceptibility, canopy vigor, and so on. There are two main strategies
growers can consider. The first uses the plant growth stage and
calendar to determine when and what to spray. The second strategy,
called post infection spraying, has come about with the advent of newer
fungicides, called Sterol Inhibitors (SIs), that have the ability to
ÔcureÕ an infection after an infection period has occurred, but before
symptoms develop. Applications are timed based on weather related
events. Weather must be monitored closely and sprays applied in
response to specific conditions that signal an infection period. Post
infection programs generally lead to a reduction in the number of
sprays applied, but increase the level of management necessary.
	In the calendar strategy growers should start disease control measures
once new growth reaches the 1 to 3 inch stage and continue those
measures at 7 to 10 day intervals through two weeks past bloom. The
interval should be relatively short during periods of rapid shoot
growth and wet weather to keep the new growth protected. The period
from budbreak through bloom usually lasts about 4 to 6 weeks, depending
on the weather, so 3 to 6 sprays may be required during this time. The
early season disease control program should include a broad spectrum
protectant EBDC fungicide such as mancozeb (Dithane, Penncozeb, etc.)
combined one of the sterol inhibitor (SI) fungicides (Nova, Bayleton,
Rubigan, Procure). Mancozeb provides good protection against black rot,
Phomopsis and downy mildew, but no protection against powdery mildew.
SIs provide excellent control of powdery mildew and, in most cases
black rot. (Rubigan and Procure are not as effective as the others on
black rot.) Mancozeb is a broad spectrum fungicide that will provide
protection for at least 7 days. It must be on all susceptible plant
parts before infections occur. The SIs are systemic, protectant, and
curative fungicides that give good protection against infection for up
to 14 days. Since the SIs provide 14 days of protection, they can be
used in every other spray if applying on a 7-day schedule.
	In a post infection program, sprays are timed according to the
occurrence of an infection period. An infection period for powdery
mildew occurs when 0.1 inch or more of rainfall occurs and the
temperatures are equal to or above 50ûF. Infection periods for black
rot are determined by the number of hours of leaf wetness at various
temperatures. See the ÔSpottÕs ChartÕ on page 9 of the 1999 Indiana
Small Fruit & Grape Spray Guide. In short, approximately nine hours of
leaf wetness are required for infection to occur at temperatures
between 60ûF and 85ûF. Once an infection period for either black rot or
powdery mildew has occurred, an application of SI fungicide must be
made within 72 hours after the start of the infection period. The
higher labeled rates of Nova (4-5 oz/A) or Bayleton (at least 4 oz/A)
should be used to insure control. The first application provides 14
days of protection. There is no need to respond to another infection
period during that time. However, once the 14 days is up, weather
monitoring begins again and an application is made when the next
infection period occurs. In order to follow a post infection program,
growers must have the ability and dedication to accurately measure
rainfall, leaf wetness, and maximum and minimum temperatures daily.
Computerized field stations are available. One problem with the
post-infection program is that it is aimed at powdery mildew and black
rot so other diseases, such as Phomopsis cane and leaf spot and downy
mildew may become a problem. Phomopsis and downy mildew are NOT
controlled by the SIs, and the 14 day interval used is too long for
protectant fungicides.
	Lots of information is available to growers on disease control in
grapes. ID-169, the 1999 Indiana Small Fruit & Grape Spray Guide has
recommendations for the standard calendar approach to grape disease and
insect control, as well as comments on post infection programs and
specific diseases. (http://www.hort.purdue.edu/hort/ext/sfg/) The
Midwest Small Fruit Pest Management Handbook has a thorough discussion
of IPM strategies for grape diseases and
insects.(http://www.ag.ohio-state.edu/~sfgnet/). Another good source of
information is the manual Grape IPM in the Northeast (NYSIPM No. 211)
which contains complete descriptions of post infection and traditional
approaches to disease and insect control and information on weather
monitoring equipment.
(http://www.nysaes.cornell.edu/ipmnet/ny/fruits/index.html). All of
these are available on the web. -Bordelon

Codling Moths:  In Lafayette, the first catch of codling moths was made
on April 30 and biofix was reached on May 3. Remember that biofix is
defined as the first sustained catch of moths, which we have
established as when 5 moths have been caught in a pheromone trap. I
will now start to accumulate heat units to estimate when the first eggs
should begin to hatch and, therefore, when I should apply my first
insecticide spray for codling moth control. See the April 21 issue of
Facts for Fancy Fruit for instructions on calculation of heat units for
codling moths. -Foster

European Red Mites:  Shortly after petal fall, growers should begin
looking for European red mites in those block of trees that were not
treated with Apollo or Savey. Initially, sampling does not need to be
very intensive. Just look at the underside of leaves in areas where you
would normally expect to see your worst mite problems, such as in Red
Delicious blocks. Using a 10X hand lens will make the mites a lot
easier to see. Until you start to see a fair number of mites, there is
no point in counting mites on a large number of leaves. However, there
is a lot of tree to tree variation, so look at leaves from several
trees. After mite populations start to build up, I recommend counting
mites on 4 leaves from each of 5 trees per block. This will take you
about 10-15 minutes. When you consider the cost of miticides (around
$60 per acre), and that by sampling you may find that you donÕt need to
spray, think about where else you can earn $240 per hour. We usually
use thresholds of 2.5 mites per leaf in early season, 5 mites per leaf
in mid season, and 7.5 mites per leaf in late season. These thresholds
are suitable for miticides such as Pyramite that kill adult and
immature mites.  Because Apollo only kills the eggs, these thresholds
may need to be adjusted when Apollo is used later in the season than in
the past. I will be investigating this idea this summer and will report
the results as soon as possible. However, for now I would recommend
using these same thresholds for Apollo. -Foster

Plum Curculio:  The warm, sunny weather weÕve had for the last five
days has been perfect to get the plum curculios moving. It is likely
that they are moving into your orchards right now.  An application of
one of our organophosphate insecticides (Guthion, Imidan, Lorsban) at
petal fall and first cover should take care of the problem. When
temperatures are cool during bloom, it is sometimes necessary to
control them at second cover, but that should not be a problem this
year. -Foster

Pollination, Fruit Set and Thinning:  Although we had a lot of rain and
cloudy weather over the last few weeks, the weather over the last week
or so has been excellent.  For many in the state, the nice weather has
coincided well with full bloom of apples, so itÕs likely that weÕll
have good fruit set in most places.  We all know that sunny weather is
good for promoting bee flight and pollination, but thatÕs only half the
battle.  The other half is turning good pollination into good
fertilization and fruit set.  Apples require cross pollination.
Suitable pollen may come from virtually any apple that blooms at the
same time within a mile or so radius.  Most varieties will pollinate
most others, except triploids do not provide pollen that will get the
job done.  Also, parent varieties usually are not very compatible with
their siblings (for example, Golden Delicious on Gala).  Many crabs
make excellent pollinizers.  Once the pollinator (bees in most cases)
transfers the pollen to the stigma of our variety, the pollen tube must
reach the ovary while it is still viable in order for fertilization and
seed set to occur.  Pollen tube growth is much faster in warmer
conditions, so this warm weather helps not only with bee flight, but
also with pollen tube growth. Since weÕre expecting heavy fruit set,
this may be the year to get a little more aggressive with your chemical
thinning.  Take a look at what you did over the last few years and how
well it worked for you.  This is the best basis to determine what to do
on your farm this year - each farm is different and selecting a
chemical thinning strategy is not a Òone size fits allÓ proposition.
Remember, early thinning gives the best results, both in terms of fruit
size and return bloom.  Early thinning is also the most risky, because
we could have a frost after thinning is done.  Each one of you must
balance the risk versus the return, and this balance is going to be
different for everyone. -Hirst

The Small Hive Beetle:  A new pest of the honey bee called the small
hive beetle, Aethina tumida, was found in Florida last year and caused
extensive damage to bee hives.  Thousands of hives were destroyed.
This pest has also been found in Georgia, South Carolina and North
Carolina.  Recently, the beetle also showed up in some packages of bees
that were shipped to Ohio.  There is a good chance that some of these
beetles could be introduced to Indiana this year. We donÕt know how
these beetles will survive in Indiana.  They are used to warm weather
because they come from South Africa.  It seems they were present in
South Carolina for two years before they were found in Florida without
causing any serious problems.  The adult beetle is small - about half a
centimeter long.  The adults and larvae eat bee brood and honey.  They
spoil the honey for the bees and they can quickly ruin the hive for the
bees, at least in Florida.  Beekeepers receiving packages of bees this
spring should be on the lookout for beetles in their hives.  But be
aware that many non-harmful beetles are often present in hives.
Indiana has just received permission under EPA section 18 to use
Coumaphos to control this beetle and also varroa mites. The Coumaphos
can be bought from Mann Lake company in the form of Checkmite Strips.
They look like the Apistan strips that are used for controlling varroa
mites, but contain a different pesticide.  But at this point, we cannot
recommend that beekeepers buy these strips unless they have a problem
with small hive beetles or varroa mites that are resistant to the
compound in Apistan strips.  Neither small hive beetles or
Apistan-resistant varroa have been found in Indiana.  Beekeepers should
use special care when handling and using the Checkmite strips because
they contain an organophosphate pesticide which is a nerve toxin.  The
EPA says they will have a zero tolerance for Coumphos in honey.  Never
leave honey supers on hives when using either Checkmite or Apistan
strips.  -Greg Hunt, Bee Specialist

Young Tree Care:  If you planted trees this spring, donÕt forget about
them.  ItÕs no good just keeping these trees alive - what weÕre trying
to achieve is maximum growth.  Aspects to especially watch on young
trees are making sure they have enough water, and ensuring good weed
control around the trees.  If you planted trees on a dwarfing
rootstock, they need support and the earlier you provide it the better.
 Also, keep in mind that the more you prune a young tree, the more you
will delay fruiting.  Minimal pruning in the early years is the key to
early fruiting. -Hirst

IHS Summer Meeting:  The summer meeting of the Indiana Horticultural
Society will be held on June 29-30 this year.  Dave and Bonnie McAfee,
County Line Orchard in Hobart IN, have graciously agreed to host the
meeting this year.  It will begin with a dinner and round table
discussion at 6:00 pm on Tuesday, June 29 to be followed by a farm tour
and presentations on Wednesday, June 30.  This will be a great
opportunity for us to see first hand the energetic and creative
marketing that the McAfeeÕs are famous for.  More details will follow
later, but write the dates on your calendar now.

Subscribing electronically:  To subscribe (or unsubscribe) to Facts for
Fancy Fruit, send a message to fff@lists.hort.purdue.edu with the
subject or body ÒsubscribeÓ (or ÒunsubscribeÓ). You can also use the
form at the web site http://www.hort.purdue.edu/fff/mailinglist.html to
submit your subscription. Electronic access is free of charge.

Coming Meetings:

May 12 - Twilight Orchard Meeting, Ohline Orchard, Allen County, 6:00
pm.  Contact Rocky Kemery at 219-481-6826

June 8 - East Central Indiana Fruit Growers Twilight Orchard Tour.
Located yet to be determined. Contact Harold Brown at 765-747-7732.

June 10 - Blueberry Growers of Indiana Summer meeting. LuedtkeÕs
Blueberries, 725 East 1400 North, Wheatfield. Contact Melvin Vankley at
219-956-3687.

June 27 - Indiana WinegrowerÕs Guild Summer meeting, Huber Orchard &
Winery, Starlight, IN. Contact Bruce Bordelon at 765-494-8212.

----------------------------------------------------------------------------
Bruce Bordelon, 1165 Dept. of Horticulture and Landscape Architecture,
Purdue University, West Lafayette, IN 47907-1165, 317/494-1301, e-mail:
bordelon@hort.purdue.edu

Peter Hirst, 1165 Dept. of Horticulture and Landscape Architecture,
Purdue University, West Lafayette, IN 47907-1165, 317/494-1323, e-mail:
hirst@hort.purdue.edu

Paul Pecknold, 1155 Dept. of Botany & Plant Pathology, Purdue
University, West Lafayette, IN 47907-1155, 317/494-4628, e-mail:
Pecknold@btny.purdue.edu

Rick Foster, 1158 Dept. of Entomology, Purdue University, West
Lafayette, IN 47907-1158, 317/494-9572, e-mail:
Rick_Foster@entm.purdue.edu

Disclaimer:  Reference to products in this publication is not an
endorsement to the exclusion of others which may be similar.  Any
person using products listed in this newsletter assumes full
responsibility for their use in accordance with current label
directions of the manufacturer.