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Control those runners

Growers taking part in the recent Scotia Horticultural Congress in Nova
Scotia heard the latest research findings on controlling runner
development in strawberry plants.

Growers taking part in the recent Scotia Horticultural Congress in Nova Scotia heard the latest research findings on controlling runner development in strawberry plants.

Two years of field trial research involving runner control of Darselect, Jewel, and Seascape using Apogee was discussed recently at the Scotia Hort Congress. Advertisement

Jennifer Smith, a graduate student working under the direction of Dr. Julia Reekie with Agriculture and Agri-Food Canada (AAFC) and Dr. Ed Reekie of Acadia University, discussed her results following two years of field trials examining runner control.

Smith conducted field trials in 2008 and 2009 on three strawberry varieties: the June-bearing Darselect and Jewel, plus the day neutral, Seascape.

The uncontrolled growth of runners (stolons) impedes fruit development in strawberries by acting as “a photosynthesis sink,” explained Smith. They also interfere with field management, costing up to $1,500 an acre to remove, she said.

Previous chemical controls have been used but “they are very nasty,” said Smith, adding that the growth regulator, Apogee, has an effective life half that of other chemicals.

Apogee, she explained, inhibits the growth hormone, gibberellin, in the stolons. While the chemical is currently registered for use in apple tree management, it is now under examination in Canada and the U.S. to assist with runner suppression, Smith said.

She did research during the winter in the field and in the lab in trials cabinets that were set up to simulate field conditions in a typical Nova Scotia season from June 1 to September 30.

During her trials, Smith applied Apogee at two concentrations: 125 ppm and 250 ppm, using three different applications: single, double and triple. Three-week intervals were used between the multiple applications.

The single spray application at either of the two concentrations doesn’t do much, explained Smith. “An increased number of spray applications really offer much better controls.”

Triple applications provide the best runner control, Smith said, although she added that the plant growth and crown size “was quite compromised. The plants were stunted.”

She found the treatment effect of Apogee more pronounced in Jewel compared to Darselect. In the day neutral, Seascape, she compared applying Apogee to an untreated control plot and removal of runners by hand, with single and double applications of Apogee at the two concentrations of 125 ppm and 250 ppm.

Smith reported that plants treated with Apogee had fewer and shorter runners than in the untreated control plot, with plants treated with two applications of Apogee at 250 ppm showing the best results and having fewer and shorter runners.

Fruit yield, she found, increased with the number of applications and the higher concentration of Apogee. By contrast, the untreated control plot had the lowest yield per plant.

Smith concluded that Apogee treatment results in fewer and shorter runners, fewer daughter plants, but bigger crowns.

A spacing trial Smith conducted involving Seascape and Apogee applications resulted in smaller plants and that more could be fit into the rows with spacings of 10 and 12 inches. Spacing, however, was not a significant factor for yield, except for the untreated control plot.

She found that hand removal of runners in the 12-inch spacing had a greater yield than one application of Apogee at 250 ppm in a 10-inch spacing.