Comments on Hedera helix documents

compiled by

Invasive Species Team staff

Joe Neal (UC Davis, joe_neal(at)ncsu.edu, 16 December 2004) has two comments about the Hedera helix document written by Jonathon Soll.

1)Joe Neal noted: "I would also suggest removing the recommendation to tank mix Scythe with Roundup. This combo seems to work fine on annual weeds, but its efficacy on perennial weeds is questionable. Limited research has been conducted with this combination applied to perennial weeds -- the one study I am aware of concluded that the combination was antagonistic and actually reduced the weed control.

2)Joe also noted: "My PhD dissertation was on the effects of glyphosate on woody ornamentals, and that research included English ivy. I conducted controlled studies in containers as well as field tests for English ivy control in the early 80s."

"In these trials the main conclusion was the critical importance of application timing. Treatments in the spring when plants had 2 to 4 newly expanded leaves provided the greatest control. Delaying treatment by only 6 weeks resulted in dramatically reduced control. Plants became increasingly more tolerant of glyphosate as the season progressed. See reference: Neal and Skroch 1985. Effects of timing and rate of glyphosate application on toxicity to selected woody ornamentals. J. Amer Soc Hort Sci 110:860-864."

"In the field applications I found that treatment with 2% by volume Roundup, in the spring when plants had 2 to 4 leaves, followed by another application about 6 weeks later (to re-growth) maximized control. When treated two years in a row in this fashion, we achieved over 95% control of established English ivy. "

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