IR-4 Ornamental Horticulture Program Research Report Cover Sheet

IR-4 Ornamental Horticulture Program Research Report over Sheet Researcher(s) harles Gilliam Affiliation: Auburn University Horticulture Department 101 Funchess Hall Auburn AL 36849 PhoneNumber: (334) 844-3045 Email: gillicl@auburn.edu Trial: 2007 AL Protocol #: 07-012 lethodim rop Safety PR# Research Target rop/plant Product EPA Reg. # Production Site Status 25648 Fern, Japanese Holly Envoy 59639-78 yrtomium fortunei lethodim Valent 25586 Fern, Autumn Envoy 59639-78 Dryopteris erythrosora lethodim Valent 25661 Fern, Marginal Wood Envoy 59639-78 Dryopteris marginalis lethodim Valent 25649 Fern, Dixie Wood Envoy 59639-78 Dryopteris x australis lethodim Valent Isoxaben rop Safety PR# Research Target rop/plant Product EPA Reg. # Production Site Status 25641 Fern, Japanese Holly Gallery 75DF 62719-145 yrtomium fortunei Isoxaben Dow AgroScie 25656 Fern, Marginal Wood Gallery 75DF 62719-145 Dryopteris marginalis Isoxaben Dow AgroScie 25642 Fern, Dixie Wood Gallery 75DF 62719-145 Dryopteris x australis Isoxaben Dow AgroScie 25606 Fern, hristmas Gallery 75DF 62719-145 Polystichum acrostichoid Isoxaben Dow AgroScie Napropramide rop Safety PR# Research Target rop/plant Product EPA Reg. # Production Site Status 26734 Fern, Japanese Holly Devrinol 50 DF 100-1060 yrtomium fortunei Napropramide Sumitomo 25658 Fern, Marginal Wood Devrinol 50 DF 100-1060 Dryopteris marginalis Napropramide Sumitomo 26738 Fern, Dixie Wood Devrinol 50 DF 100-1060 Dryopteris x australis Napropramide Sumitomo rop Safety PR# Research Target rop/plant Product EPA Reg. # Production Site Status 26480 Fern, Japanese Holly Kade G yrtomium fortunei

to ferns from various herbicides. (Ornamental Protocol Number: 07-012) Objective To determine phytotoxicity of selected herbicides to hardy ferns commonly grown in nurseries. Materials and Methods. Six fern cultivars were potted on May 1, 2007 into a medium of pine bark and builders sand (6:1 ratio); amendments (per yd. 3 ) included 14.0 lbs. 17-5-11 Polyon, 5.0 lbs. dolomitic lime and 1.5 lbs. Micromax. Ten single plant replications per herbicide treatment were potted for Brillance Autumn, Eastern Wood, Japanese Holly and Tassel ferns; eight single plant replications were done for hristmas ferns and seven for Dixie Wood ferns. All ferns were potted into trade gallon containers and adequately spaced to allow for growth. Irrigation was provided by regular, cyclic, overhead impact sprinklers. Herbicide treatments included: Devrinol 50DF (napropaminde) at 2.0, 4.0 and 8.0 pounds active ingredient per acre (lbs. ai/a), Gallery 75DF (isoxaben) at 0.5, 1.0 and 2.0 lbs. ai/a, Kade G (prodiamine) at 0.75, 1.5 and 3.0 lbs. ai/a and Envoy (clethodim) at 34, 68, and 124 ounces product per acre (oz P/A). Liquid herbicides were applied with a O2 backpack sprayer with a 8003 nozzle at 20 gallons per acre (gpa). Granular herbicides were applied via handheld shaker. Not all ferns received all herbicide treatments. One group of ferns per cultivar was left as non-treated control plants. Devrinol, Gallery and Kade treatments were first applied on 2 May 2007; skies were partly cloudy, temperature was 84 0 F, relative humidity was 32% and wind was S at 7mph. Ferns received a second application of these herbicides on 27May 2007; skies were partly cloudy, temperature was 82 0 F, relative humidity was 60% and wind was SE at 7mph. Ferns were first treated with Envoy on 30 May 2007; skies were cloudy, temperature was 77 0 F, relative humidity was 46% and wind was E at 8mph. Envoy was applied a second time on 27 May 2007; skies were partly cloudy, temperature was 82 0 F, relative humidity was 60% and wind was SE at 7mph. Plants were rated at 1, 2, 4 weeks following the first application of herbicides and at 1, 2, 4, 6 and 8 weeks following the second application of herbicides. Injury (phytotoxicity) was rated on scale of 0 through 100 where 0 = no injury and 100 = dead plant. Growth data was taken on all ferns at the close of the test. Growth index = plant height + width of the plant at it s widest point + width perpendicular to the widest point / 3.. Results. There was no visual injury evident in any ferns for the duration of the study regardless of treatment. Growth Index. Brillance Autumn fern were treated with Kade at 0.75, 1.5 and 3.0 lb ai/a and Envoy at 34, 68, and 124 oz product/a (Table 1). Growth indices in all treatments were similar to the non-treated control plants. Plants treated with Kade at the 0.75 and 1.5 lb ai/a rate were larger than those treated with 3.0 lb ai/a. hristmas ferns were treated with Gallery at 0.5, 1.0 and 2.0 lb ai/a and Kade at rates listed previously. Again all plants were similar in size to the non-treated control plants. Dixie Wood ferns were treated with Devrino at 2.0, 4.0 and 8.0 lb ai/a, and Gallery, Kade and Envoy

at the rates previously listed. All ferns were similar in size or larger than the non-treated control plants. Eastern Wood fern were treated similarly to the Dixie Wood ferns and there were no differences in growth indices among any treatments. Japanese Holly ferns received the same treatments as Dixie Wood and Eastern Wood ferns. All ferns were similar in size or larger than the non-treated plants except those treated with Gallery at 2.0 lb ai/a., which had the smallest growth indices. Tassel ferns were treated with Kade at the previously listed rates (0.5, 1.5 and 3.0 lb ai/a). All plants were similar in size or larger than the non-treated control plants, however, Tassel ferns treated with the 3.0 lb ai/a rate were smaller than those treated with the 0.75 lb ai/a rate. In summary the herbicides tested appeared to be safe for use on the hardy ferns evaluated in this test. There was a tendency for ferns (hristmas, Dixie Wood, and Japanese Holly) treated with Gallery at the 2.0. lb ai/a rate to be smaller in size than those treated with other herbicides/rates; however, only with the Japanese Holly fern was the difference statistically significant.

Table 1. Effects of Selected Herbicides on Growth of Various Ferns Herbicide Treatment Growth Index 1 Brillance hristmas Dixie Eastern Japanese Tassel Autumn Wood Wood Holly 2.0 lbs. ai/a 4.0 lbs. ai/a 8.0 lbs. ai/a 0.5 lbs. ai/a 1.0 lbs. ai/a 2.0 lbs. ai/a Kade @ 0.75 lbs. ai/a Kade @ 1.5 lbs. ai/a Kade @ 3.0 lbs. ai/a 34 oz. P/A 68 oz. P/A 124 oz. P/A Non-treated ontrol. 2. 50.4 ab 23.8 a 25.5 abcd... 51.3 ab 25.0 a 24.5 bcd... 53.0 ab 26.0 a 24.9 abcd.. 29.3 ab 51.0 ab 22.9 a 25.8 abcd.. 29.3 ab 55.2 ab 24.5 a 24.3 cd.. 26.8 b 48.0 b 25.8 a 23.4 d. 32.3 ab 30.3 ab 56.8 a 27.3 a 27.2 abcd 18.6 a 33.1 ab 30.8 a 52.8 ab 26.7 a 27.0 abcd 17.4 ab 29.6 c 31.5 a 54.3 ab 23.5 a 28.7 a 15.9 b 31.8 abc. 52.0 ab 25.5 a 27.2 abcd. 30.4 bc. 49.4 ab 24.9 a 28.2 abc. 30.4 bc. 48.9 ab 24.1 a 28.4 ab. 30.6 bc 28.3 ab 47.5 b 23.1 a 28.1 abc 16.4 b 1 Growth Index is the mean of a plant s height, width at it s widest point and width perpendicular to the widest point; growth data were taken on 6/25/07. 2 Fern did not receive this herbicide treatment. Means with the same letter are not significantly different (P<.05).