09/16/1991

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.

-30-

By:
Katie Smith