Can you improve your success with Four-Flap grafting?

Can you improve your success with Four-Flap grafting?
By Bill Goff
The four-flap grafting method, as
best I can determine, was first
described by Jerry Vanerwegen of
Tennessee in 1975 (Vanerwegen,
1975). It has since been written
about and recommended in numerous publications, websites and videos. A quick Internet search will find
many descriptions of the procedure
from various states. A consensus
view is that it is the most reliable
method for propagating pecans, especially for inexperienced grafters.
We have been using the procedure for many years in our cultivar
testing program, and more recently
to graft thousands of seedling trees
we planted in orchards. Because our
grafting effort was expanding, we
have evaluated various aspects of the
procedure in an attempt to speed it
up and improve take.
Following are some steps we have
found to improve the procedure or
make it more efficient.
•Use large caliper scion wood
wlth^prQininent buds. Interestingly,
Vanerwegen's original article described using ""one half to one-inch
stock with graftwood the same size.""
He also reported 140 live grafts of
142 attempts. Over the years, many
have fudged on his original size recommendations, and grafted smaller
sticks, which reduces success. Figure
1 illustrates pecan graftwood and my
expectation from our experience of
the percent live according to graftwood size and condition. Carry a
dime and a quarter in your pocket
and try to use graftwood between
those diameters. Smaller than a
dime can be used but will be lower
percentage take. Larger than a quarter is hard to work with, and it is difficult to find previous-season wood
with prominent buds where the wood
diameter is that large.
•Store the w^Q_d_jn__nip_i_st,_c_edaE
shavings^ After many occasions of
Goff is a research and extension
horticulturist at Auburn University.
PECAN SOUTH
unwrapping moldy wood from newpapers, we have settled on cedar
shavings as the packing material of
choice. Cedar shavings can be purchased in the pet section of department or pet stores, as it is commonly
used as bedding material for pets
because fleas don't like it. The sticks
come out of storage greener and
fresher when packed in cedar shavings. We cut the sticks the first week
of February, pack them in moist (not
soaking wet) cedar shavings, and
store them in plastic containers or
plastic bags at about 36 degrees F.
We do not wax the ends, as research
shows this to be unnecessary
(Nesbitt et al., 2002).
•Standardize the__p_r_oce_djjre. In
working with grafting crews over the
years, I've found that everyone does
it a little differently. Some make long
cuts, some make short cuts. Some
leave long sticks above the graft, others short. Some have one set of buds
Fig. 1. The four-flap graft method works
best with vigorous scionwood one halfinch (about dime-sized) to one-inch (about
quarter-sized) in diameter. Smaller wood
than this reduces success. Percentages
indicated represent our experiences and
experiments with wood of comparable
sizes and condition.
left above the
wraps, others several. These variations were tolerated before
we
found out what
works best, but no longer. Here's how
I train them now:
- Choose a stick between the
diameter of a dime and a quarter.
The stick should have prominent
buds, like the 2 sticks on the right in
Fig. 1. Select 2 prominent buds near
the top of the stick, and cut the stick
off one-half inch above the uppermost bud set of buds) (Fig. 2 - right).
The uppermost set of buds is the
""primary"" set, and the buds at the
node below that are the secondary or
""reserve"" set. Next measure one
inch below the reserve buds plus one
knife-blade length and cut the bottom of the stick at that point (Fig. 2 left).
- Dip the cut sticks in ice water
- cedar shavings. Advice given me
over the years from experienced
grafters on whether the sticks should
be wet has run the gamut. I remember being told at Simpson Nursery
years ago that the grafting crew
stops when rain begins, as the grafts
wouldn't take if water came in contact with the cut surfaces. On the
other hand, Monte Nesbitt carries a
spray bottle of water and sprays the
cut surfaces to moisten them. George
Ray McEachern puts the sticks in his
mouth, I've heard, to keep them
moist. I remember Bluefford Hancock saying that keeping the graftwood too wet was the single bigge=r
reason for graft failure.
By all means, keeping the graftwood too wet in storage reduces success. However, excess drying, especially of the exposed cambium at
time of grafting, is equally harmful
We minimize drying during storage
by putting graftwood in sealed plastic containers or plastic bags p^.^k=J.
with moist, but not overly wet. cfcdar
shavings and keeping the sticks cool
at about 36 degrees F. We minimize
drying during the transport to the
field by packing the wood in ice
chest, with ice, and still in moist
cedar shavings.
— A step we have added recently
that I believe has contributed to our
improved 95-percent plus success
rate is to dip the sticks immediately
after cutting into an ice-water-cedar
shavings bath. This arrests danger of
drying, and keeps sticks cool. The
details, which I think are key to success, are as follows:
1. Cut off the top of the tree to be
grafted. Push the knife into the tree
See FOUR FLAP, Page 8
Jug of ice
water + cedar
shavings
Fig. 3. As soon as cuts are made on stick
of scionwood, very quickly place the stick
in a jug of ice water with cedar shavings
to keep it moist, cold, and fresh while
flaps are prepared on tree.
Secondset ofbuds
from the top
(reserve buds)
Cut off the stick 1 inch plus knifeblade length below the reserve
buds
Fig. 2. Cut off the top of the stick 1/2 inch above a prominent set of buds (primary set
of buds) (right). Below the second set of buds from the top (the secondary or reserve
set) measure one inch plus one knife blade length and cut off bottom of the stick (left).
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Fig. 4. Wrap the graft union only with
grafting tape. Then wrap the graft union
plus the top of the stick with Parafilm,
Parafilm grafting tape, or Buddy tape.
Foil and plastic bags are unnecessary.
The wraps do not need to ever be
--~s4 if 4 mil grafting tape is used.
Uppermost set of
buds from the top
(primary buds) not
seen on other side
of stick.
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Jiinn 20(1!)
Continued from Page 5
Four-flap
County pecan field days in Texas are held throughout the state.
Field days are Texas tradition and helpful
in disseminating management information
By Bill Ree
Extension Program Specialist II
- IPM (Pecan)
Texas AgriLife Extension
I must say that one of the
favorite aspects of my position is having the opportunity to attend and
participate in county pecan field days
across the state. These county field
days have been a part of Texas Pecan
Growers educational program for
more than 50 years. These gatherings of producers, homeowners and
pecan enthusiasts are not only social
events, but an important part of the
educational process. During these
field days you can hear presentations
on horticultural, disease control,
entomology, economics, wildlife management and even participate in
grafting demonstrations.
Many of the field days are held
outside in an orchard and you cannot
find a better setting for a meeting
than sitting in the shade of some
majestic natives.
Annually I manage to attend
between 12 and 18 field days, most of
which occur in the spring and my
part centers on discussing pecan nut
casebearer management. With pecan
nut casebearer being the most important nut-feeding insect, a lot of attention and effort is devoted to its management.
In 1996 the pecan nut casebearer
pheromone trap became commercialPECAN SOUTH
ly available to producers and from
this came the opportunity for producers to monitor and report real time
activity. The reporting of real time
activity (adult flights), initially
through mass media outlets such as
radio, newsletters and newspaper
articles has now expanded to the
internet. New internet sites such as
http://pecan.ipmpipe.org
and
http://PNCforecast.tamu.edu
provide producers with real time information on PNC activity and allow
producers to make their own predictions.
Now that this new information is
available to producers, the challenge
becomes how to make growers aware
of these new sources. I believe here
you can see the value of county field
days.
In a survey/questionnaire I handed out this spring, from 335 returns
across 11 field days, only 44 percent
of the attendees were aware of the
new information sources. Hopefully,
through the information obtained
during the meetings, the remaining
56 percent were able to utilize the
information to help them make a better management decision.
County field days have been and
will continue to be an important part
of a pecan educational program and I
encourage you to support your county program by attending one of these
educational events. I
grafting
to prepare for pulling back the flaps,
but don't pull them back yet. Put a
small rubber band around the tree.
Cut the 4 flaps on the stick of graftwood. Begin the cuts one inch below
the reserve buds and make the cuts
the length of the knife blade.
2. Immediately plunge the stick
into an ice water - cedar shavings
bath (Fig. 3). We use a one gallon
milk jug, fill it with ice, and put two
handfuls of cedar shavings in the jug
with the ice water.
3. With the cut stick in the ice
water, return to the tree, pull back
the 4 flaps, and cut out the stick of
wood. The stick of wood cut out
should be the length of the knife
blade. Next slide the rubber band up
to hold the flaps together.
4. Immediately retrieve the cut
stick and quickly insert it still wet
between the 4 flaps. The stick is still
wet and moistens the flaps.
5. Wrap the graft union with
grafting tape. 1 like 4 mil best, as it is
easy to work with and will deteriorate before girdling the tree so doesn't have to be removed.
6. Wrap the entire union and the
stick with Parafilm or Parafilm grafting tape or Buddy tape (Fig. 4). These
are similar materials which allow gas
exchange but reduce drying. This
final step has been added by most of
the good grafters I work with, and
they all like it. Notice that we have
eliminated the use of aluminum foil
and plastic bags in the original procedure, as trials we have done showed
they did not result in better graft
take than the method above. A further advantage of the method we use
is that no follow-up removal of bags,
foil or tape is required
Try the steps above and I am confident you will be pleased with the
results. I
Literature Cited
Nesbitt, M.L., W. D. Goff, and.L. A.
Stein. 2002. Effect of scionwood
packing moisture and cut-end sealing on pecan graft
success.
HortTechnology. 12(2)257-260.
Vanerwegen, Jerry, 1975. A new
grafting procedure. Pecan South 2
(2): 70-71.