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ALABAMA PECAN GROWERS CONVENTION
FAIRHOPE, Ala.__--Which pecan cultivar has the most resistance to pecan
scab? Does weed control give a boost to young pecan trees? How much
sunlight do pecan trees need?
The answers to these and many other pecan production issues were given
during the 31st annual Alabama Pecan Growers convention held Sept. 19-20
at the Gulf Coast Substation in Fairhope.
The two-day meeting drew some 230 participants and included a wide variety
of speakers on issues such as pest control, cultivar selection and marketing.
Pecan scab was one of the main concerns during the meeting. "There
has been a heavy incidence of scab this year because of the rains,"
said Bill Goff, an Auburn University horticultural researcher and Extension
specialist. "That has been bad for producers, but it has been good
for test sites."
Goff noted that scab, a fungus disease affecting leaves and young shoots
and nut shucks of pecan, can reduce a tree's ability to manufacture
food but primarily affects and destroys nut shucks, causing nuts to
drop or reducing their size and quality.
Studies to identify scab-resistant cultivars are being conducted through
the Alabama Agricultural Experiment Station (AAES) at Auburn University
at five different test sites throughout the state. Goff said results
vary at each location, but Sumner and Melrose varieties were both scab
resistant and met other criteria necessary to make them viable for commercial
production at all locations. Elliott, Jubilee and Dixie cultivars also
showed promise.
Paul Estes, an Auburn University entomologist, discussed phylloxera
problems in Alabama. He explained that there are actually three types
of phylloxera affecting pecan trees. The most damaging is pecan phylloxera,
often called stem phylloxera. Southern pecan phylloxera and pecan leaf
phylloxera also may be found in Alabama, but are not as economically
important.
According to Estes, the phylloxera is an insect that is closely related
to aphids. These insects form galls on the tree as a part of their reproductive
process. "Timing of treatment is the most important aspect of control,"
Estes said. "Insecticides must be applied at bud break. A second
application should be made 10 days later, and spot treatment of trees
that are infested is necessary."
Estes noted that there has been some interest in biological control
of phylloxera using parasites and predators. "We cannot yet rely
on biological control of phylloxera. Chemical control and maybe phylloxera-resistant
cultivars seem to be our best bet," he added.
A five-year-old weed test at the Substation, an outlying research unit
of the AAES, has shown the importance of weed control in young orchards.
Mike Williams, a weed scientist at Auburn, said that studies have shown
total weed control underneath the tree's canopy provides the best growth
opportunity for young trees.
He noted that chemical mowing of weeds, applying enough chemical to
keep weeds low but not kill them, has also been studied and is somewhat
effective. But, he added, producers should consider cost when choosing
a weed-control program.
"If you use chemicals at a killing rate, it will cost more per
application than the mowing rate," he said. "But there is
no residual activity. What you spray on is what you get and you may
have to reapply chemicals several times during the growing season."
Bruce Wood, research horticulturist with the Southeastern Fruit and
Nut Lab in Byron, Ga., discussed the need for sunlight penetration for
pecans. "We need to optimize production, and one very common limiting
factor is sunlight," he said.
Wood said studies have shown that more sunlight yields more food for
the tree resulting in better nut production. "You can't saturate
the tree with sunlight," he said, noting that this means there
is an unlimited benefit from sunlight. He said this is particularly
important as trees reach maturity.
"If sunlight is limited, this limits the ability of other inputs
to work efficiently," he said. The optimum distance between trees
in an orchard is not yet known, though studies indicate the best planting
arrangement for pecans to optimize sunlight use is in northeast/southwest
rows in a hexagonal pattern.
Other program participants from Auburn University included: James Hurst,
Cooperative Extension Service ag economist who discussed the potential
for farm liability; John McVay, Extension entomologist who discussed
insecticide choices and rates; Ted Tyson, Extension ag engineer who
discussed irrigation options for pecans. Jim Bannon, director of the
E.V. Smith Research Center in Shorter (the main AAES research unit),
discussed new pecan studies being established at the Center. Mike Horne
of Andersonville, Ga., and president of the Georgia Pecan Growers, discussed
his experiences in marketing and growing pecans.
Ronnie McDaniel, associate superintendent at the Substation, led field
tours of the Substation pecan study plots with help from Superintendent
Emmett Carden and Assistant Superintendent Malcomb Pegues. A panel discussion
on production and marketing of pecans was held featuring Horne and Alabama
producers Bob Ainsley of Lillian, Harry Amling of Opelika, Curly Clemons
of Foley, Robert Dade of Fairhope, Billy Deakle of Irvington, Gerald
Lawrence of Elmore and Stanely Zinner of Robertsdale.
The meeting also featured selection of officers for the coming year
and the presentation of several awards.
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By:
Katie Smith
Sept. 1991
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