IR-4 Ornamental Horticulture Program Research Report Cover Sheet

Transcription

1 IR-4 Ornamental Horticulture Program Research Report over Sheet Researcher(s) harles Gilliam Affiliation: Auburn University Horticulture Department 101 Funchess Hall Auburn AL PhoneNumber: (334) Trial: 2008 AL ProjectTitle: Efficacy for Broadleaf Weeds (Bittercress, Oxalis, Spurge) Protocol #: PR# Research Target rop/plant Product EPA Reg. # Production Site Status Bittercress BroadStar 0.25G V Field ontainer ardamine hirsuta Flumioxazin Valent Bittercress EX Field ontainer ardamine hirsuta Mesotrione + 2 oth Syngenta Bittercress ardamine hirsuta Gallery 75DF Isoxaben Dow AgroScie Greenhouse Bittercress V G - Field ontainer ardamine hirsuta Imazasulfuron Valent Spurge BroadStar 0.25G V Field ontainer Euphorbia sp. Flumioxazin Valent Spurge Freehand G (BAS Greenhouse Euphorbia sp. Dimethenamid-p + BASF Spurge Pendulum 2G Greenhouse Euphorbia sp. Pendimethalin BASF Spurge Euphorbia sp. Tower (BAS 656h Dimethenamid-p BASF Greenhouse

2 IR4 Bittercress: Early Postemergence ontrol harles Gilliam and Greg reech Objective: To evaluate selected herbicides for early postemergence control of bittercress. Materials and Methods Two hundred ten 3 inch containers were filled with a potting medium of pine bark and builders sand (6:1 ratio); amendments (per yd. 3 ) to the medium included 14.0 lbs Polyon, 5.0 lbs. dolomitic lime and 1.5 lbs. Micromax. On 3 April 2008, 70 pots were over-seeded with bittercress (25 seeds/pot) and placed under irrigation in a greenhouse. Another 70 containers were over-seeded on 10 April 2008 and placed in the same greenhouse. The final 70 pots were over-seeded just prior to the application of herbicides on 17 April This created three seeding groups of 70 pots each: Group 1. bittercress with cotyledons or one leaf; Group 2. bittercress with two to four leaves; and Group 3. pre-emergent bittercress. In each seeding group, nine single-pot replications were provided for each herbicide treatment; one group of 9 pots was left as a non-treated control. Only 7 replications per seeding treatment received Gallery. Herbicide treatments were applied on 17 April, At the time of treatment, the temperature was 66 of, relative humidity was 37%, winds were SSW at 6 m.p.h. and skies were clear. Irrigation was provided by regular, cyclic, overhead sprinklers. Granular herbicides treatments included: BroadStar G NF at 75 and 150 pounds of product per acre (lbs. P/A), Mesotrione G at 100 and 150 lbs. P/A, V G at 75 and 150 lbs. P/A. Granular herbicides were applied via handheld shaker. Gallery 75 WDG was applied at a rate of 1.0 pounds of active ingredient per acre (lbs. ai/a) using a O2 backpack sprayer with an 8003 nozzle at 20 gallons per acre (gpa). Bittercress were evaluated at 7, 14 and 21 days after treatment (DAT); seeding group 1 and seeding group 2 were observed for injury; weed numbers per pot were counted for group 3. Injury was rated on a scale of 1 to 10 where 1 = no injury and 10 = dead plant. Fresh weed weights were taken for all containers at 21 DAT. Data were analyzed using ANOVA and Duncan s multiple -range test (P <.05). Results Bittercress, cotyledon to one leaf At 7 DAT injury was pronounced among bittercress treated with Mesotrione G, V G or Gallery WDG at any rate. Mean injury ratings for these treatment groups were 6.0 or greater. There was no injury to bittercress treated with BroadStar G at 7 DAT. However by 14 DAT bitterecress treated with 150 lbs P/A began to exhibit injury symptoms (3.6). Ratings for bittercress treated with either rate of V G or Gallery WDG exceeded 8.0. Damage to plants receiving Mesotrione ranged from 6.8 to 7.2. All plants receiving Gallery or V at the higher rate were dead by 21 DAT. Damage remained extensive among all other herbicide treatments except those treated with BroadStar at 75 lbs. P/A which showed no injury. Ratings ranged from 6.7 for bittercress receiving the higher rate of BroadStar to 9.1 for plants treated with V at 75 lbs. P/A. All bittercress, except those treated with BroadStar at the lower rate (15.9g), had significantly less fresh weed weights than that of the non-treated control group (17.9g). Other fresh weights ranged from 0.0g, for plants receiving V at the higher rate, to 11.6g for bittercress treated with BroadStar at 150 lbs. P/A.

3 Bittercress, two to four leaves Injury at 7 DAT was significant among all treated bittercress though not as pronounced among plants treated with BroadStar. Phytotoxicity ratings among all other treatment groups exceeded 6.0 and was most severe in bittercress receiving Gallery (8.4) or Mesotrione at either rate (8.0). By 14 DAT, injury had increased in almost all treatments. Damage among plants treated with either Mesotrione, V or Gallery was rated in excess of 7.0. Bittercress receiving BroadStar at the lower rate had fully recovered by 14 DAT and exhibited no injury symptoms for the rest of the study. Plants treated with Gallery or V at either rate were dead by 21 DAT. Injury was also substantial among bittercress receiving either rate of Mesotrione; damage was rated at 7.9 and 9.7, respectively. Damage was not quite as extensive to plants treated with BroadStar at 150 lbs. P/A (5.2). Fresh weed weights for all treated containers were significantly smaller than that of the non-treated control group (15.4g). ontainers treated with Mesotrione, V or Gallery had mean weights less than 3.0g. Fresh weed weights ranged from 0.0g for pots treated with either rate of V to 12.0g for containers receiving BroadStar at 75 lbs. P/A. Bittercress, preemergence. No bittercress were present at 7 or 14 DAT in any containers and mean weed numbers remained low in all treated containers at 21 DAT. Bittercress were observed only pots receiving either BroadStar at 75 lbs. P/A or V at 150 lbs. P/A (0.1 weeds/pot, respectively). Non-treated control containers had a mean weed number of 5.1. Fresh weed weights were non-existent for all containers treated with a herbicide. The mean fresh weed weight for non-treated control containers was 4.1g.

4 Table 1. Effects of selected herbicides on bittercress, cotyledon to one leaf. Plant Injury Ratings 1 Fresh Weights 2 7 DAT 3 14 DAT 21 DAT 21 DAT Treatment Rate 4/24/08 5/1/08 5/8/08 5/8/08 Broadstar lbs/a d5 1.0 d 1.0 e 15.9 a Broadstar lbs/a 1.1 d 3.6 c 6.7 d 11.6 b Mesotrione 100 lbs/a 6.0 c 6.8 b 7.9 c 7.5 c Mesotrione 150 lbs/a 6.8 b 7.2 b 8.4 bc 5.8 c V lbs/a 7.1 b 8.4 ab 9.1 ab 1.8 d V lbs/a 7.0 b 9.4 a 10.0 a 0.0 d Gallery lbs ai/a 8.4 a 9.9 a 10.0 a 0.6 d Non treated ontrol ***** 1.0 d 1.0 d 1.0 e 17.9 a 1 Plant injury ratings on scale of 1 to = no injury, 10 = dead plant. 2 Fresh weights measured in grams 3 DAT = Days after treatment 4 lbs/a = Pounds of product per acre. 5 Means separated using Duncan's Multiple Range Test at p = ai/a = Pounds of active ingredient per acre.

5 Table 2. Effects of selected herbicides on bittercress, two to four leaf. Plant Injury Ratings 1 Fresh Weights 2 7 DAT 3 14 DAT 21 DAT 21 DAT Treatment Rate 4/24/08 5/1/08 5/8/08 5/8/08 Broadstar lbs/a e5 1.0 d 1.0 d 12.0 b Broadstar lbs/a 2.9 d 4.6 c 5.2 c 8.4 c Mesotrione 100 lbs/a 6.4 c 7.1 b 7.9 b 3.0 d Mesotrione 150 lbs/a 7.6 b 8.8 a 9.7 a 1.9 ed V lbs/a 8.0 ab 9.0 a 10.0 a 0.0 e V lbs/a 8.0 ab 8.9 a 10.0 a 0.0 e Gallery lbs ai/a 8.4 a 8.9 a 10.0 a.07 ed Non treated ontrol ***** 1.0 f 1.0 d 1.0 d 15.4 a 1 Plant injury ratings on scale of 1 to = no injury, 10 = dead plant. 2 Fresh weights measured in grams 3 DAT = Days after treatment 4 lbs/a = Pounds of product per acre. 5 Means separated using Duncan's Multiple Range Test at p = ai/a = Pounds of active ingredient per acre.

6 Table 3. Effects of selected herbicides on pre emergent bittercress. Plant Injury Ratings 1 Fresh Weights 2 7 DAT 3 14 DAT 21 DAT 21 DAT Treatment Rate 4/24/08 5/1/08 5/8/08 5/8/08 Broadstar lbs/a a5 0.0 a 0.1 b 0.0 b Broadstar lbs/a 0.0 a 0.0 a 0.0 b 0.0 b Mesotrione 100 lbs/a 0.0 a 0.0 a 0.0 b 0.0 b Mesotrione 150 lbs/a 0.0 a 0.0 a 0.0 b 0.0 b V lbs/a 0.0 a 0.0 a 0.1 b 0.0 b V lbs/a 0.0 a 0.0 a 0.0 b 0.0 b Gallery lbs ai/a 0.0 a 0.0 a 0.0 b 0.0 b Non treated ontrol ***** 0.0 a 0.0 a 5.1 a 4.1 a 1 Plant injury ratings on scale of 1 to = no injury, 10 = dead plant. 2 Fresh weights measured in grams 3 DAT = Days after treatment 4 lbs/a = Pounds of product per acre. 5 Means separated using Duncan's Multiple Range Test at p = ai/a = Pounds of active ingredient per acre.

7 IR4 Spurge: Early Postemergence ontrol hris Marble and harles Gilliam Objective: To evaluate selected herbicides for early postemergence control of spurge. Materials and Methods Postemergence spurge control was tested at two different stages of growth, cotyledon to 1 leaf, 2 to 4 leaf, and also for preemergence control. On July 31, 2008, 3.5 inch pots were filled with pinebark:sand (6:1) (v:v) amended with 14 lbs of Polyon (8 9 month control release fertilizer) 5.0 lbs of dolomitic lime, and 1.5 lbs Micromax on a per yard basis, placed in full sun, and over head irrigated. Spurge grew for 14 days until treatment date and reached the 2 to 4 leaf stage. On August 7, 2008, 3.5 inch pots were filled with same substrate and grew for 7 days, reaching the cotyledon stage prior to treatment. On August 14, 2008, 3.5 inch pots were filled with same substrate to be used for preemergence evaluation and all pots (cotyledon to 1 leaf, 2 4 leaf, and pots newly filled) were treated with herbicide. At the time of treatment, the temperature was 84 F, relative humidity was 51%, winds were NW at 12 m.p.h., and skies were partly cloudy. Pots filled on the day of treatment were then over seeded with spurge seed (10 seeds per container) immediately after herbicide treatment to evaluate preemergence control. All pots were placed in full sun and received over head irrigation. Treatments included Broadstar G (flumioxazin) at 150 and 300 lbs per acre, FreeHand 1.75G (dimethenamid + pendimethalin) at 200 and 400 lbs per acre, Tower 6.0 E (dimethenamid) at 1.5 and 3.0 lbs aia (active ingredient per acre), Pendulum 3.3 E (pendimethalin) at 2 and 4 lbs aia and a non

8 treated control. Broadstar and FreeHand treatments were applied with a hand shaker. Spray treatments (Tower and Pendulum) were applied at 20 gallons per acre with a O 2 backpack sprayer (80 04 nozzle) at 25 psi. Each of the 3 growth stages contained 9 treatments with 6 single pot replicates per treatment. Pots were arranged by growth stage (preemergence, cotyledon, and 2 to 4 leaf) in a completely randomized design. Subjective injury ratings on a scale of 1 to 10 (1 = no injury, 10 = dead) were taken at 10, 20, and 30 days after treatment (DAT) on cotyledon and 2 to 4 leaf stage fresh weights were taken on all pots at 30 DAT. Data was analyzed using Duncan s Multiple Range test at P = 0.05 for means separation. Results Preemergence All herbicide treated pots were weed free at 10 and 20 DAT, and at 30 DAT pots treated with Broadstar (150 and 300 lbs/a), Tower (1.5 and 3.0 lbs/aia), and FreeHand at 400 lbs/a also remained weed free (data not shown). There were no statistical differences in fresh weights of any herbicide treated pot (Table 1). otyledon to One Leaf At 10 DAT, Broadstar at the 150 lbs/a rate had little effect on the spurge (rating of 2.1), while the 300 lbs/a rate had excellent activity (9.0) (Table 2). This trend continued at 20 DAT, however by 30 DAT, spurge began to recover. Spurge treated with FreeHand at 200 lbs/a were injured at 10 and 20 DAT, but began to recover at 30 DAT. However, when FreeHand was applied at 400 lbs/a, by 30 DAT, all pots were given an injury rating of 9 or higher. Tower at 1.5

9 lbs/aia had excellent activity throughout the study, and at 3 lbs/aia had an injury rating of 10.0 on all dates. Pendulum provided similar results at both rates. Fresh weights show no statistical differences in treatments recieving Broadstar at 150 lbs/a and the non treated control (Table 1). Fresh weights also indicate Broadstar at 300 lbs/a was similar to FreeHand at 200 lbs/a while FreeHand at 400 lbs/a, Tower at both rates, and Pendulum at both rates, provided the best control. Two to Four Leaf Broadstar had little effect on spurge in the 2 to 4 leaf stage at either rate and were statistically similar to the non treated control on all dates in injury ratings, however fresh weights show Broadstar provided some degree of control (Tables 1, 2). FreeHand at 200 and 400 lbs/a had activity at 10 DAT, and were similar to Tower and Pendulum at the 1.5 and 2.0 lbs/aia rates, respectively. Tower at 3.0 lbs/aia (8.8) and Pendulum at 4 lbs/aia (7.2) provided the best control postemergence of spurge at 10 DAT. At 20 DAT, the best control was achieved with FreeHand at 400 lbs/a, Tower at 3.0 lbs/aia, and Pendulum at both rates. By 30 DAT, spurge treated Tower at 3.0 lbs/aia and both rates of Pendulum had significantly more injury than all other treatments. Fresh weights taken at 30 DAT show Broadstar had the least effect of any herbicide (Table 1). FreeHand at 200 and 400 lbs/a had similar control to Tower at 1.5 lbs/aia and Pendulum at 2.0 lbs/aia. Tower at 3.0 lbs/aia and Pendulum at 4.0 lbs/aia had similar fresh weights to FreeHand at 400 lbs/a.

10 Table 1. Spurge (Euphorbia maculata) preemergence and early postemergence fresh weights Z. Growth Stage Treatment Rate Pre emergence otyledon 2 4 Leaf Broadstar 150 lbs Y 0.0 b W 5.6 a 6.4 b Broadstar 300 lbs 0.0 b 0.8 bc 6.7 b FreeHand 200 lbs 0.0 b 1.8 b 1.7 cd FreeHand 400 lbs 0.0 b 0.0 c 1.3 cd Tower 1.5 lbs aia X 0.0 b 0.0 c 2.5 c Tower 3.0 lbs aia 0.0 b 0.0 c 0.1 d Pendulum 2 lbs aia 0.0 b 0.0 c 0.6 cd Pendulum 4 lbs aia 0.0 b 0.0 c 0.1 d Non treated **** 0.8 a 6.6 a 12.0 a Z Fresh weights measured in grams and taken at 30 days after treatment. Y Rate given at pounds per acre. X aia = active ingredient per acre. W Means separated using Duncan's Multiple Range Test.

11 Table 2. Spurge (Euphorbia maculata) early postemergence injury ratings Z. Growth Stage otyledon 2 4 Leaf Treatment Rate 10 DAT Y 20 DAT 30 DAT 10 DAT 20 DAT 30 DAT Broadstar 150 lbs X 2.1 d V 2.0 c 1.0 d 1.17 d 1.3 d 1.0 d Broadstar 300 lbs 9.0 ab 9.1 a 6.7 b 2.0 d 2.2 d 1.0 d FreeHand 200 lbs 6.3 c 7.6 b 3.9 c 3.8 c 5.7 bc 5.0 bc FreeHand 400 lbs 8.3 b 9.7 a 9.9 a 5.2 c 6.8 ab 6.0 b Tower 1.5 lbs aia W 9.3 ab 9.6 a 10.0 a 4.7 c 4.7 c 4.0 c Tower 3.0 lbs aia 10.0 a 10.0 a 10.0 a 8.8 a 8.5 a 8.7 a Pendulum 2 lbs aia 9.1 ab 9.9 a 10.0 a 4.7 c 7.7 a 8.0 a Pendulum 4 lbs aia 9.7 a 10.0 a 10.0 a 7.2 b 8.7 a 8.7 a Non treated **** 1.0 e 1.3 c 1.0 d 1.0 d 1.2 d 1.0 d Z Ratings on scale of 1 to 10 (1 = no injury, 10 = dead plant). Y DAT = Days after treatment. X Rate given at pounds per acre. W aia = active ingredient per acre. V Means separated using Duncan's Multiple Range Test at P = 0.05.