AmericanFarm.com

Researchers meet to talk about current orchard state

By JANE W. GRAHAM
AFP Correspondent

CANA, Va. (June 27, 2017) — Researchers from Virginia Tech’s Alson H. Smith Jr. Agriculture Research and Extension Center in Winchester were on hand at the recent Tree Fruit Growers Orchard Tour to discuss thinning of fruit as well as disease and insect pest and control measures. 
The unusual weather the region has experienced was cited as a cause of the unique development of both the crops and their pests.
This has included heavy rain and abnormally high temperatures, especially early in the season.
The group walked among rows of trees at Berrier Farms where early apples were being picked and packed even earlier than usual because they are ripening ahead of schedule.
Prior to visiting Berrier Farms, the group met at Leonard Orchard where they heard two speakers from Winchester, Serif M. Serif, an assistant professor of pomology, and J. Christopher Berg, a professor of entomology.
Serif discussed the work his team has done using different thinning materials in mature Fuji and Gala apples.
They worked to assess thinning efficiency of various combinations of two thinning treatments, 6-BA and NAA.
They studied the carbohydrate thinning model and were able to reduce the rate of all chemical applications by 50 percent, for the first application, he said, and increased it by 30 percent for the second.
He provided his audience with graphic data from the testing of thinning treatments using an apple carbohydrate thinning model and fruit retention.
Serif reported that the Gala apples are more sensitive to chemical thinning applications than Fuji, something that did not surprise him.
“Natural thinning due to high temperatures on April 29 has resulted in 30 to 60 percent abscission,” or the flowers and leaves falling off prematurely, Serif said.
Promoting the return bloom in apples is important, the researcher stressed.
“The initiation of the next year flower buds occurs two to six weeks from bloom,” Sheriff wrote in his hand-out. “Therefore, if the tree is exhausted by producing more fruits and/or vegetative tissues during this period, the initiation of flower buds will be negatively affected and less return bloom will be obtained.”
Thinning by hand or chemicals can help the trees produce the flower buds for next year, he added.
Some plant growth regulators, particularly NAA and ethephon, after the thinning period ends can also promote bud initiation and subsequently return bloom.
Berg discussed some of the insects that orchardists may encounter in their fruit and control methods.
Among these are codling moths, oriental fruit moths and brown marmorated stink bugs. 
He also noted that the Japanese beetles are arriving several weeks earlier this year.
The third stop on the tour was at Hill Brothers and Sons where they saw an experiment of growing apple trees close together, supported by metal frames.