D. Kopec, Extension Turfgrass Specialist
J. Gilbert, A. Boettcher
Abstract
Pre-emergence herbicides including Dimension (dithiopyr) Stomp (pendimethalin) Ronstar (oxadiazon), Barricade (prodiamine), Surflan (oryzalin), Gallery (isoxaben), Team (treflan plus benefin) were applied in various formulations and rates to assess weed control of southwestern cupgrass (Erichloaacuminata). Dimension clay granules at 0.38 and 0.50 lb ai/A rates provided season long control with one application. Barricade also produced equal control as Dimension. Ronstar at the 3.0 lb ai/A rate also had 96-100% control throughout the season along with Best fertilizer (Team herbicide with fertilizer blended). Dimension granules were slightly better than the liquid (EC formulation). Repeat applications of select treatments at six weeks were erroneously omitted. Turfgrass density and percent bermudagrass plot cover in mid-May were effected by herbicide treatments.
Introduction
Turfs in southern Arizona are subject to infestation with summer annual weeds, which include crabgrass (Digitaria spp.) and southwestern cupgrass (Eriochloa acuminata). These species are quite competitive in turfs of even modest density, and reproduce from the germination of abundant seeds produced by late summer. Pre-emergence control can be an effective (and preferred) means of controlling these weeds. Such pre-emergence control calls for the application of herbicides in late February or early March in the low desert valleys of Phoenix and Tucson. A replicated field trial was conducted at Mesa Community College to assess the weed control properties of selected herbicides, and herbicide/fertilizer combinations.
Materials and Methods
The turf site included a large area of known infestations of grassy weeds, which was exclusively that of southwestern cupgrass. The turf during the winter was that of annual ryegrass (Lolium multiflorum), which was mowed at 2.5 inches with a riding rotary mower. The turf site was irrigated to prevent visual stress.
Applications of pre-emergence herbicides were made on March 9, 1993. Post emergence treatments (where applicable) were made on July 7, 1993. A scheduled repeat application for five herbicide treatments (split application) was erroneously omitted. Liquid applications were made using a two nozzle boom at 20 inch spacing. Plot size was 40" x 84". Carrier volume was 85.5 gal/A. Nozzle size was 8004 and tank pressure was 30 psi. Granular applications were made using a Gandy 36" width drop spreader, calibrated for each treatment. Treatments were incorporated within 2 hours after application with 1/2 inche of supplemental irrigation.
A total of 33 treatments were applied. Turf plots were evaluated for cupgrass control based on the percent of the control plots.
Results
Weed Control:
Weed control for the treatments were determined on June 9, July 7, August 16 and September 27. Southwestern cupgrass was not present on the May 13 evaluation date. The herbicide treatment effect was highly significant on all dates, except on July 7.
The percent weed control is provided in Table 4. On June 9, (92 DAT) 100% weed control was realized by the following treatments:
1) Prodiamine 0.75 lbs ai/A
2) Best Fertilizer/Team 3.0 lbs ai/A
3) Ronstar 3.0 lbs ai/A
4) Dimension -G- 0.38 lbs ai/A
5) Dimension -G- 0.50 lbs ai/A
6) Pendimethalin/Fert 3.0 lbs ai/A
7) Pendimethalin Exp -G- 4.9 lbs ai/A
8) Stomp 4.9 lbs ai/A
There were eleven other treatments which exhibited 95-99% mean weed control levels. Best fertilizer contained the herbicide 'TEAM' (Benefin+Trifluralin) as a commercial product.
Treatments which had 85% or less control at this time included BEST-FERTILIZER product at 1.5 lbs ai/A, GALLERY/SURFLAN/FERTILIZER (233 lbs product/A), SURFLAN AS. at 2.0 lbs ai/A, and Dimension liquid at 0.125 lbs ai/A (Table 4).
On July 8 (121 DAT), weed control ranged from 13% to 100%. The Dimension granule (-G-) products at 0.5 and 0.38 lbs ai/A had 100% control. Dimension liquid at 0.50 lbs ai/A had 98% control. Eight products had 95-99% control. These included pendimethalin fertilizer (3.0 lb ai/A), Prodiamine at 1.0 lb ai/A, GALLERY/TEAM-Fertilizer (375 lbs product/A) and Ronstar at 3.0 lbs ai/A. SURFLAN AS. at the rates tested here had 67% or less weed control (Table 4).
On August 16 (160 DAT), weed control mean treatment values ranged from 0 to 100% (full control). Dimension clay granules (-G-) at both the 0.38 and 0.50 lb ai/A rates had 100% control, along with pendimethalin-fertilizer (3.0 lb ai/A), Prodiamine (1.0 lb ai/A) and GALLERY/TEAM-Fertilizer (375 lb prod/A). Seven other treatments had 95-99% control, as well (Table 4).
The post emergence applications of Quinclorac/MSMA, and Illoxan/Surflan, had 71% and 0% control, respectively. All together, eleven treatments had weed control levels of less than 90% (Table 4).
The last evaluation for weed control was on September 22 (197 DAT). Dimension clay granules (-G-) and Pendimethalin + fertilizer at the high rate of 3.0 lbs ai/A had 100% control. Seven other treatments had 96-99% control of cupgrass. These included Dimension (-G-) at 0.38 lbs ai/A, Prodiamine at both the 0.75 lb ai/A and 1.0 lb ai/A rates, Dimension -G- at 0.25 lb ai/A, Gallery + Team fertilizer at 375 lbs product/A, Best fertilizer at 3.0 lbs ai/A, and Ronstar at 3.0 lbs ai/A.
Table 4. Pre-emergent control of Southwestern cupgrass on four dates
in 1993 expressed as [1-(treatment/control)] x 100.
| JUNE 9 (92 DAT) | JULY 8 (121 DAT) | AUGUST 16 (160 DAT) | SEPTEMBER 22 (197 DAT) |
| TREATMENT | % | TREATMENT | % | TREATMENT | % | TREATMENT | % |
| DIMENSION -G-
0.50 lb/A |
100 | DIMENSION -G-
0.50 lb/A |
100 | DIMENSION -G-
0.50 lb/A |
100 | DIMENSION -G-
0.50 lb/A |
100 |
| DIMENSION -G-
0.38 lb/A |
100 | DIMENSION -G-
0.38 lb/A |
100 | DIMENSION -G-
0.38 lb/A |
100 | PENDIMETHALIN+FERT
3.0 lb/A |
100 |
| STOMP
4.90 lb/A |
100 | PENDIMETHALIN+FERT
3.0 lb/A |
99 | PENDIMETHALIN+FERT3.0 lb/A | 100 | DIMENSION -G-
0.38 lb/A |
99 |
| PRODIAMINE
0.75 lb/A |
100 | PRODIAMINE
1.0 lb/A |
98 | PRODIAMINE
1.0 lb/A |
100 | PRODIAMINE
0.75 lb/A |
99 |
| BEST-FERT
3.0 lb/A |
100 | GALLERY TEAM FERT
375 lb prod./A |
98 | GALLERY+TEAM FERT 375 lb prod/A | 100 | PRODIAMINE
1.0 lb/A |
98 |
| RONSTAR
3.0 lb/A |
100 | RONSTAR
3.0 lb/A |
98 | RONSTAR
3.0 lb/A |
99 | DIMENSION -G-
0.25 lb/A |
97 |
| PENDIMETHALIN+FERT
3.0 lb/A |
100 | DIMENSION -L-
0.50 lb/A |
98 | DIMENSION -G-
0.25 lb/A |
99 | GALLERY+TEAM/FERT
375 lb prod./A |
96 |
| PENDIMETHALIN EXP
4.90 lb/A |
100 | DIMENSION -G-
0.25 lb/A |
96 | BEST-FERT
3.0 lb/A |
99 | BEST FERT
3.0 lb/A |
96 |
| PRODIAMINE
1.0 lb/A |
99 | BEST FERT
3.0 lb/A |
95 | PENDIMETHALIN EXP 4.90 lb/A | 99 | RONSTAR
3.0 lb/A |
96 |
| DIMENSION -L-
0.50 lb/A |
99 | PRODIAMINE
0.75 lb/A |
95 | DIMENSION -L-
0.50 lb/A |
98 | DIMENSION -L-
0.50 lb/A |
95 |
| GALLERY+TEAM FERT
375 lb prod./A |
99 | PENDIMETHALIN EXP
4.90 lb/A |
92 | PENDIMETHALIN FERT 1.5 lb/A | 98 | STOMP
4.90 lb/A |
94 |
| DIMENSION -G-
0.25 lb/A |
99 | SURFLAN FERT
2 lb/A |
92 | SURFLAN FERT
2 lb/A |
95 | SURFLAN FERT
2 lb/A |
90 |
| PENDIMETHALIN+FERT
1.5 lb/A |
98 | PENDIMETHALIN FERT
1.5 lb/A |
89 | STOMP
4.90 lb/A |
94 | XL
3.0 lb/A |
87 |
| GALLERY TEAM FERT
250 lb prod./A |
98 | PENDIMETHALIN EXP
2.45 lb/A |
88 | DIMENSION -L-
0.38 lb/A |
93 | PRODIAMINE
0.5 lb/A |
86 |
| PRODIAMINE
0.5 lb/A |
97 | XL
3.0 lb/A |
88 | XL
3.0 lb/A |
92 | PENDIMETHALIN EXP
2.45 lb/A |
83 |
| SURFLAN AS
1.5 lb/A |
96 | STOMP
4.90 lb/A |
86 | PRODIAMINE
0.75 lb/A |
91 | DIMENSION -L-
0.38 lb/A |
81 |
| PENDIMETHALIN EXP
2.45 lb/A |
96 | DIMENSION -L-
0.38 lb/A |
85 | PENDIMETHALIN EXP 2.45 lb/A | 91 | PENDIMETHALIN FERT
1.5 lb/A |
80 |
| DIMENSION -L-
0.38 lb/A |
95 | PRODIAMINE
0.5 lb/A |
84 | PRODIAMINE
O.5 lb/A |
86 | PENDIMETHALIN EXP
4.90 lb/A |
69 |
| SURFLAN FERT
2 lb/A |
95 | GALLERY+TEAM FERT
250 lb prod./A |
80 | QUINCLORAC+MSMA1 0.5+2 lb/A | 71 | GALLERY+TEAM/FERT
250 lb prod./A |
68 |
| XL
3.0 lb/A |
93 | STOMP
2.45 lb/A |
75 | SURFLAN AS
2.0 lb/A |
70 | SURFLAN AS
2.0 lb/A |
63 |
| STOMP
2.45 lb/A |
90 | BEST FERT
1.5 lb/A |
73 | STOMP
2.45 lb/A |
70 | QUINCLORAC+MSMA2
0.5+2 lb/A |
58 |
| XL
1.5 lb/A |
87 | SURFLAN AS
1.5 lb/A |
67 | XL
1.5 lb/A |
66 | STOMP
2.45 lb/A |
52 |
| BEST FERT
1.5 lb/A |
85 | SURFLAN AS
2.0 lb/A |
59 | GALLERY+TEAM FERT 250 lb prod/A | 62 | SURFLAN AS
1.5 lb/A |
49 |
| GALLERY+SURF/FERT
233 lb prod./A |
80 | XL
1.5 lb/A |
42 | GALLERY+SURF FERT 233 lb prod/A | 51 | GALLERY+SURF/FERT
233 lb prod./A |
41 |
| SURFLAN AS
2.0 lb/A |
65 | GALLERY+SURF FERT
233 lb prod/A |
36 | SURFLAN AS
1.5 lb/A |
50 | BEST FERT
1.5 lb/A |
40 |
| DIMENSION -L-
0.125 lb/A |
47 | DIMENSION -L-
0.125 lb/A |
13 | BEST-FERT
1.5 lb/A |
46 | XL
1.5 lb/A |
14 |
| DIMENSION -L-
0.125 lb/A |
12 | DIMENSION -L-
0.125 lb/A |
0 | ||||
| SURFLAN ILLOXAN1 1+0.5 lb/A | 0 | SURFLAN+ILLOXAN2
1+0.5 lb/A |
0 |
1Days after treatment (DAT) for these products was 39 on August 16, 1993.
2Days after treatment (DAT) for these products was 76 on September 22, 1993.
Issued in furtherance of Cooperative Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, James A. Christenson, Director, Cooperative Extension, College of Agriculture & Life Sciences, The University of Arizona. The University of Arizona is an equal opportunity, affirmative action institution. The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.