1999 Iowa Turfgrass Research Report

In this study various preemergent herbicide and herbicide plus fertilizer formulations were screened for efficacy in controlling annual grass weed species in turfgrass. The study was conducted at the Iowa State University Horticulture Research Station near Ames, IA in established 'Nassau' Kentucky bluegrass that had a heavy crabgrass infestation in 1997. The soil was a Nicollet (fine-loamy, mixed, mesic Aquic Hapludoll) with an organic matter content of 3.35%, a pH of 6.85, 5 ppm P, and 93 ppm K.

The study was arranged as a randomized complete block. Individual plot size was 5 x 5 ft with three replications. Thirty-three treatments were included in single and split applications with a fertilized control and an untreated control (Table 1).

Preemergent applications were made on April 29, 1998 before crabgrass germination. It was 54° F with overcast skies and a northeast wind at 10 mph. Crabgrass was detected in the untreated controls on June 10. Sequential (POST) applications of treatments 2 - 9 were made on June 16 (6 to 8 weeks after initial applications). Temperatures were in the mid 70's and it was mostly sunny with a light NW wind. The crabgrass plants in the untreated controls were in the 1- to 2-leaf stage. On July 1, sequential applications of treatments 10-15 and 21-25 were made. It was 80° F and mostly sunny with northwest winds at 5-10 mph. Crabgrass in the untreated controls was in the 1- to 4-leaf stage.

Liquid formulations were applied at 30 psi with a carbon dioxide backpack sprayer equipped with TeeJetâ #8006 flat fan nozzles. Liquids were diluted into 287 ml of water which translates to an application rate of three gal/1000 ft². Granular materials were applied using 'shaker dispensers'.

Visual turf quality data were taken weekly from May 5 through September 2 (Tables 2 and 3). Quality was assessed using a 9 to 1 scale with 9 = best, 6 = lowest acceptable, and 1 = worst quality. The plot was checked for phytotoxicity on each of these dates and none was detected.

Annual grass populations were estimated as percentage crabgrass cover per plot. These data were taken weekly from July 7 through September 2 (Table 4). Annual grass control was determined by calculating percentage reductions in crabgrass cover as compared with the untreated controls (Table 5). Broadleaf population data for oxalis, clover, dandelion, and black medic were taken on September 2 (Table 6).

All data were analyzed using the Statistical Analysis System (SAS, Version 6.12) and the Analysis of Variance (ANOVA) procedure. Fisher's Least Significant Difference (LSD) tests were used to compare means separation.

The quality of turf treated with herbicide plus fertilizer formulations was better than the untreated controls on May 5 (Table 2). By June 4, most of the fertilizer effects on quality were gone. Improved quality also was detected in turf receiving sequential applications of herbicide plus fertilizer formulations on either June 16 or July 1. Nineteen of the materials produced significantly better mean quality than the untreated controls (Table 3).

There were significant differences in percentage crabgrass cover on all data collection dates (Table 4). Seventeen of the materials maintained percentage crabgrass cover æ 5.3% for the duration of the study and twenty materials suppressed cover to æ 10% for this period. Twenty-four herbicide formulations produced mean percentage cover æ 8.7%.

Crabgrass cover reductions were significantly different on all collection dates (Table 5). Twenty herbicides reduced crabgrass cover by Ñ 95% as compared with the untreated controls on July 7 and 10 herbicides provided 100% control on that date. By July 29, the level of control had decreased for some of the formulations but 21 herbicides were still providing Ñ 90% control. By September 2, 16 herbicides were still reducing crabgrass cover Ñ 90% as compared with the untreated controls. Thirteen herbicides provided Ñ 90.0% crabgrass control for the duration of the study (Table 5).

Dandelion was the only broadleaf weed species that was distributed among all of the plots (Table 6). There were significantly fewer dandelions in turf treated with eight of the herbicides as compared with the untreated controls. Some of the largest dandelion populations were found in turf treated with herbicides that provided excellent control of crabgrass. In these areas, dandelions could more easily establish because of less competition from crabgrass and other weed species.

Oxalis, black medic, and clover distributions were sporadic. The efficacy of the tested herbicides in controlling these species, therefore, could not be determined from these data.

Table 1. Materials and rates for the 1998 Pre- & Postemergent Annual Weed Control Study.

	Material	(PRE) Rate (g product/ft2)	(POST) Rate (g product/ft2)
1.	Untreated control	N/A	N/A
2.	S-80961	2.06	none
3.	S-80961	2.06	2.06
4.	S-80971	2.06	none
5.	S-80971	2.06	2.06
6.	S-81621	1.56	none
7.	S-81621	1.56	1.56
8.	S-81611	1.53	none
9.	S-81611	1.53	1.53
		(PRE) Rate lb a.i./A	(POST) Rate lb a.i./A
10.	Team Pro NAF-324 0.86GR2	1.5	1.5
11.	Team Pro NAF-324 0.86GR2	2.0	none
12.	Pendimethalin 0.86GR2	1.5	1.5
13.	Pendimethalin 0.86GR2	2.0	none
14.	Dimension 0.10 GR2	0.38	none
15.	Barricade 0.22 GR2	0.5	none
		Rate lb a.i./A	Timing of application
16.	BAS051434H Drive 75DF3	0.75	PRE
17.	BAS051434H Drive 75DF3	0.50	PRE
18.	BAS 514 0.57GR3	0.75	PRE
19.	BAS 514 0.57GR3	0.50	PRE
20.	Pendimethalin 60WDG3*	3.00	PRE
21.	BAS051434H Drive 75DF + MSO3	0.75 1.0%	POST
22.	BAS051434H Drive 75DF + MSO3	0.50 1.0%	POST
23.	BAS 514 0.57GR3	0.75	POST
24.	BAS 514 0.57GR3	0.50	POST
25.	Dimension 1EC + NIS3	0.50 0.50%	POST
26.	Dimension 1EC4	0.25	PRE
27.	Dimension 0.164FG AND4454	0.25	PRE
28.	Dithiopyr 1.06XF 98-0254	0.25	PRE
29.	Dithiopyr 0.89XF 98-0264	0.25	PRE
30.	Dithiopyr 2.20XF 98-0294	0.25	PRE
31.	Dimension 40WP4	0.25	PRE
32.	Fertilized control4	N/A	PRE

¹These materials are being screened for The Scotts Company.

²These materials are being screened for Dow AgriSciences.

³These materials are being screened for BASF.

⁴These materials are being screened for Rohm and Haas and were applied with methylene urea (39-0-0) at 4 lb/1000 ft².

Initial applications (PRE) were made on April 29, Scott's (trt 2-9) sequential applications at 6 to 8 WAT on June 16, Dow (trt 10-15) sequential applications at 8 to 10 WAT on July 1, and BASF (trt 21-25) POST applications on July 1.

 

Table 2. Visual quality¹ of Kentucky bluegrass treated for the 1998 Pre- & Postemergent Annual Weed Control Study (May 5 - July 7).

	Material	May 5	May 13	May 19	May 27	June 4	June 10	June 16	June 24	June 30	July 7
1.	Untreated control	7.0	7.0	6.3	6.0	6.0	5.3	5.7	6.0	6.0	6.0
2.	S-8096	8.7	7.0	7.7	7.7	6.3	6.7	7.3	6.0	6.7	6.3
3.	S-8096	8.7	7.0	7.3	7.7	6.0	6.7	7.7	8.0	9.0	8.7
4.	S-8097	8.3	7.3	8.0	7.7	6.7	7.0	7.3	6.0	6.3	7.3
5.	S-8097	8.3	7.7	8.0	9.0	6.7	7.0	7.3	8.0	8.7	8.0
6.	S-8162	7.3	6.7	6.3	7.0	6.3	5.7	6.7	6.0	6.0	6.0
7.	S-8162	8.0	6.7	6.3	6.7	6.0	5.7	7.3	8.0	8.0	6.7
8.	S-8161	7.0	7.0	7.3	8.0	6.7	6.0	6.3	6.0	6.3	6.7
9.	S-8161	8.7	7.7	7.0	7.0	6.3	6.3	6.3	8.0	8.0	7.0
10.	Team Pro NAF-324 0.86GR	7.3	7.7	7.7	7.7	6.7	6.0	7.3	6.0	6.3	8.7
11.	Team Pro NAF-324 0.86GR	9.0	7.0	7.7	7.7	6.0	6.0	7.0	6.0	6.3	6.3
12.	Pendimethalin 0.86GR	8.7	6.7	7.7	8.3	6.7	6.7	7.3	6.0	6.3	8.3
13.	Pendimethalin 0.86GR	8.0	6.7	8.0	8.7	6.0	7.0	7.7	6.0	7.0	6.3
14.	Dimension 0.10 GR	8.3	7.0	8.0	8.3	6.7	6.7	7.7	6.0	6.7	6.3
15.	Barricade 0.22 GR	9.0	7.0	7.0	7.0	6.0	6.3	7.3	6.0	6.3	6.0
16.	BAS051434H Drive 75DF	7.3	6.0	5.7	5.3	6.0	5.0	5.0	6.0	5.7	6.3
17.	BAS051434H Drive 75DF	7.7	6.3	5.7	5.7	6.0	5.0	5.7	6.0	6.3	6.0
18.	BAS 514 0.57GR	8.0	7.0	6.0	5.7	6.0	5.0	5.7	6.0	6.0	6.0
19.	BAS 514 0.57GR	8.0	6.7	6.0	6.0	6.0	5.3	6.3	6.0	6.0	6.0
20.	Pendimethalin 60WDG	8.0	6.7	6.0	6.7	6.0	5.3	6.3	6.0	6.0	6.0
21.	BAS051434H Drive 75DF	7.7	7.0	6.3	6.7	6.0	5.3	6.3	6.0	6.0	6.3
22.	BAS051434H Drive 75DF	7.3	6.7	6.3	6.0	6.3	5.3	6.3	6.0	6.0	6.0
23.	BAS 514 0.57GR	8.0	6.7	6.3	6.0	6.3	5.0	5.7	6.0	6.0	6.3
24.	BAS 514 0.57GR	7.3	7.0	6.0	6.3	6.0	5.0	5.0	6.0	6.0	6.0
25.	Dimension 1EC + NIS	7.0	7.0	6.0	6.0	6.0	5.3	5.7	6.0	6.0	6.0
26.	Dimension 1EC	8.3	7.7	7.3	9.0	6.3	7.7	9.0	6.0	7.3	6.7
27.	Dimension 0.164FG AND445	7.7	7.3	7.3	8.3	7.0	7.3	8.3	6.0	7.3	7.3
28.	Dithiopyr 1.06XF 98-025	8.7	7.0	7.0	8.7	6.3	7.3	7.7	6.0	7.7	7.0
29.	Dithiopyr 0.89XF 98-026	8.0	7.0	7.0	8.0	6.0	7.0	8.7	6.0	8.0	7.0
30.	Dithiopyr 2.20XF 98-029	7.7	7.3	7.7	8.3	6.3	7.7	8.3	6.0	7.7	7.0
31.	Dimension 40WP	7.3	7.7	7.3	8.3	7.0	7.3	8.0	6.0	7.0	7.7
32.	Fertilized control	8.0	7.0	7.0	8.3	6.7	8.3	8.3	6.0	7.3	6.3
	LSD0.05	1.0	NS	1.1	1.0	0.6	1.1	1.4	--	0.9	1.1

¹Visual quality was assessed using a 9 to 1 scale with 9 = best, 6 = lowest acceptable and 1 = worst quality.

Initial applications (PRE) were made on April 29, Scott's (trt 2-9) sequential applications at 6 to 8 WAT on June 16, Dow (trt 10-15) sequential applications at 8 to 10 WAT on July 1, and BASF (trt 21-25) POST applications on July 1.

NS = means are not significant at the 0.05 level.

-- = means comparisons tests are not valid for these data.

Table 3. Visual quality¹ of Kentucky bluegrass treated for the 1998 Pre- & Postemergent Annual Weed Control Study (July 14 - September 2).

	Material	July 14	July 29	Aug 4	Aug 11	Aug 18	Aug 27	Sept 2	Mean
1.	Untreated control	6.0	7.0	7.0	7.0	7.0	7.0	6.0	6.4
2.	S-8096	6.0	7.3	7.0	7.0	7.0	7.0	6.0	6.9
3.	S-8096	7.0	7.3	7.3	7.0	7.0	7.0	6.0	7.4
4.	S-8097	6.3	7.0	7.0	7.0	7.0	7.0	6.0	7.0
5.	S-8097	6.7	7.3	7.3	7.0	7.0	7.0	6.0	7.5
6.	S-8162	6.3	7.0	7.0	7.0	7.0	7.0	6.0	6.5
7.	S-8162	6.3	7.0	7.0	7.0	7.0	7.0	6.0	6.9
8.	S-8161	6.3	7.0	7.0	7.0	7.0	7.0	6.0	6.7
9.	S-8161	6.7	7.0	7.3	7.0	7.0	7.0	6.0	7.1
10.	Team Pro NAF-324 0.86GR	7.0	7.7	8.0	7.0	7.0	7.0	6.0	7.1
11.	Team Pro NAF-324 0.86GR	6.3	7.0	7.0	7.0	7.0	7.0	6.0	6.8
12.	Pendimethalin 0.86GR	7.0	7.3	7.7	7.0	7.0	7.0	6.0	7.2
13.	Pendimethalin 0.86GR	6.0	7.0	7.0	7.0	7.0	7.0	6.0	7.0
14.	Dimension 0.10 GR	6.0	7.0	7.0	7.0	7.0	7.0	6.0	7.0
15.	Barricade 0.22 GR	6.0	7.0	7.0	7.0	7.0	7.0	6.0	6.8
16.	BAS051434H Drive 75DF	6.0	7.0	7.0	7.0	7.0	7.0	6.0	6.2
17.	BAS051434H Drive 75DF	6.0	7.0	7.0	7.0	7.0	7.0	6.0	6.3
18.	BAS 514 0.57GR	6.0	7.0	7.0	7.0	7.0	7.0	6.0	6.4
19.	BAS 514 0.57GR	6.0	7.0	7.0	7.0	7.0	7.0	6.0	6.4
20.	Pendimethalin 60WDG	6.3	7.0	7.0	7.0	7.0	7.0	6.0	6.5
21.	BAS051434H Drive 75DF	6.3	7.0	7.0	7.0	7.0	7.0	6.0	6.5
22.	BAS051434H Drive 75DF	6.0	7.0	7.0	7.0	7.0	7.0	6.0	6.4
23.	BAS 514 0.57GR	6.0	7.0	7.0	7.0	7.0	7.0	6.0	6.4
24.	BAS 514 0.57GR	6.0	7.0	7.0	7.0	7.0	7.0	6.0	6.3
25.	Dimension 1EC + NIS	6.0	7.0	7.0	7.0	7.0	7.0	6.0	6.4
26.	Dimension 1EC	6.7	7.0	7.0	7.0	7.0	7.0	6.0	7.2
27.	Dimension 0.164FG AND445	6.3	7.0	7.0	7.0	7.0	7.0	6.0	7.1
28.	Dithiopyr 1.06XF 98-025	6.7	7.0	7.0	7.0	7.0	7.0	6.0	7.1
29.	Dithiopyr 0.89XF 98-026	7.0	7.0	7.0	7.0	7.0	7.0	6.0	7.1
30.	Dithiopyr 2.20XF 98-029	6.7	7.3	7.7	7.0	7.0	7.0	6.0	7.2
31.	Dimension 40WP	6.7	7.3	7.3	7.0	7.0	7.0	6.0	7.2
32.	Fertilized control	6.7	7.0	7.3	7.0	7.0	7.0	6.0	7.1
	LSD0.05	0.7	NS	0.5	--	--	--	--	0.3

¹Visual quality was assessed using a 9 to 1 scale with 9 = best, 6 = lowest acceptable and 1 = worst quality.

Initial applications (PRE) were made on April 29, Scott's (trt 2-9) sequential applications at 6 to 8 WAT on June 16, Dow (trt 10-15) sequential applications at 8 to 10 WAT on July 1, and BASF (trt 21-25) POST applications on July 1.

NS = means are not significant at the 0.05 level.

-- = means comparisons tests are not valid for these data.

 

Table 4. Percentage crabgrass cover¹ in Kentucky bluegrass treated for the 1998 Pre- & Postemergent Annual Weed Control Study.

	Material	July 7	July 14	July 24	July 29	Aug 4	Aug11	Aug 18	Aug 27	Sept2	Mean
		________________________________________ % _________________________________________
1.	Untreated control	13.3	14.0	26.7	26.7	33.3	25.0	35.0	38.3	53.3	29.5
2.	S-8096	0.7	0.7	1.0	0.3	2.0	2.7	2.3	2.3	3.7	1.7
3.	S-8096	0.0	0.0	0.0	0.0	0.0	0.0	0.3	0.3	0.3	0.1
4.	S-8097	0.0	0.0	0.7	0.3	0.7	0.7	0.0	3.3	3.7	1.0
5.	S-8097	0.3	0.0	0.0	0.0	0.7	0.3	0.3	1.0	1.0	0.4
6.	S-8162	0.0	0.3	1.7	1.7	2.0	0.3	3.7	5.0	5.3	2.2
7.	S-8162	0.0	0.0	0.3	0.0	0.3	0.0	1.0	0.0	1.7	0.4
8.	S-8161	0.0	0.0	0.0	0.0	0.0	0.0	0.7	1.0	2.0	0.4
9.	S-8161	0.0	0.7	0.7	0.7	0.7	1.0	1.7	0.7	1.7	0.9
10.	Team Pro NAF-324 0.86GR	0.3	0.3	0.0	2.0	0.3	0.3	0.7	0.7	1.7	0.7
11.	Team Pro NAF-324 0.86GR	0.0	0.0	0.3	1.0	1.0	1.0	2.7	2.3	3.7	1.3
12.	Pendimethalin 0.86GR	1.7	2.0	8.3	6.7	5.0	3.3	6.7	5.0	12.0	5.6
13.	Pendimethalin 0.86GR	0.3	1.3	2.7	1.3	5.3	4.3	6.7	8.3	8.3	4.3
14.	Dimension 0.10 GR	0.3	0.0	0.0	0.0	0.0	1.0	1.7	2.0	2.0	0.8
15.	Barricade 0.22 GR	0.3	0.7	2.7	1.3	1.0	1.0	2.0	2.3	3.7	1.7
16.	BAS051434H Drive 75DF	9.0	4.0	25.7	18.3	16.7	21.7	20.0	33.3	36.7	20.6
17.	BAS051434H Drive 75DF	11.7	13.3	21.7	18.3	23.3	20.0	25.0	35.0	41.7	23.3
18.	BAS 514 0.57GR	2.0	7.0	10.3	10.7	13.7	9.3	13.3	21.7	26.7	12.7
19.	BAS 514 0.57GR	11.7	9.3	25.0	28.3	28.3	23.3	30.0	41.7	56.7	28.3
20.	Pendimethalin 60WDG	0.0	0.3	1.7	1.3	3.3	0.7	2.0	2.0	3.7	1.7
21.	BAS051434H Drive 75DF	0.0	0.0	0.7	1.0	0.0	0.0	1.3	2.3	2.3	0.9
22.	BAS051434H Drive 75DF	0.0	0.0	0.3	0.0	2.0	1.0	4.3	4.0	4.0	1.7
23.	BAS 514 0.57GR	0.3	0.7	3.3	0.7	3.7	3.0	6.7	7.0	10.0	3.9
24.	BAS 514 0.57GR	3.0	6.3	10.0	8.3	11.7	9.3	18.3	26.7	35.0	14.3
25.	Dimension 1EC + NIS	2.3	2.3	3.0	1.0	3.7	2.0	5.3	2.3	3.7	2.9
26.	Dimension 1EC	0.7	1.0	4.3	1.7	2.3	2.3	6.3	10.0	12.0	4.5
27.	Dimension 0.164FG AND445	0.3	0.0	1.0	0.7	1.7	0.7	2.0	0.7	3.7	1.2
28.	Dithiopyr 1.06XF 98-025	6.7	6.7	7.0	16.7	12.0	12.0	10.3	13.7	20.0	11.7
29.	Dithiopyr 0.89XF 98-026	2.0	3.7	7.7	7.3	8.7	4.3	6.3	10.3	13.3	7.1
30.	Dithiopyr 2.20XF 98-029	1.0	1.3	8.7	5.7	12.0	6.7	11.7	13.3	18.3	8.7
31.	Dimension 40WP	0.7	1.7	3.7	3.7	4.0	2.3	5.3	6.7	8.3	4.0
32.	Fertilized control	5.3	6.0	20.0	16.7	16.7	13.3	18.3	30.0	31.7	17.6
	LSD0.05	5.8	6.9	10.1	9.3	11.8	8.7	9.8	14.1	16.0	9.0

¹These figures represent the area per plot covered by crabgrass.

Initial applications (PRE) were made on April 29, Scott's (trt 2-9) sequential applications at 6 to 8 WAT on June 16, Dow (trt 10-15) sequential applications at 8 to 10 WAT on July 1, and BASF (trt 21-25) POST applications on July 1.

Table 5. Percentage crabgrass cover reductions¹ in Kentucky bluegrass treated for the 1998 Pre- & Postemergent Annual Weed Control Study.

	Material	July 7	July 14	July 24	July 29	Aug 4	Aug 11	Aug 18	Aug 27	Sept 2	Mean
		_______________________________________ % __________________________________________
1.	Untreated control	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
2.	S-8096	95.0	95.2	96.3	98.8	94.0	89.3	93.3	93.9	93.1	94.3
3.	S-8096	100.0	100.0	100.0	100.0	100.0	100.0	99.0	99.1	99.4	99.7
4.	S-8097	100.0	100.0	97.5	98.8	98.0	97.3	100.0	91.3	93.1	97.3
5.	S-8097	97.5	100.0	100.0	100.0	98.0	98.7	99.0	97.4	98.1	98.7
6.	S-8162	100.0	97.6	93.8	93.8	94.0	98.7	89.5	86.9	90.0	93.8
7.	S-8162	100.0	100.0	98.8	100.0	99.0	100.0	97.1	100.0	96.9	99.1
8.	S-8161	100.0	100.0	100.0	100.0	100.0	100.0	98.1	97.4	96.2	99.1
9.	S-8161	100.0	95.2	97.5	97.5	98.0	96.0	95.2	98.3	96.9	97.2
10.	Team Pro NAF-324 0.86GR	97.5	97.6	100.0	92.5	99.0	98.7	98.1	98.3	96.9	97.6
11.	Team Pro NAF-324 0.86GR	100.0	100.0	98.8	96.3	97.0	96.0	92.4	93.9	93.1	96.4
12.	Pendimethalin 0.86GR	87.5	85.7	68.8	75.0	85.0	86.7	81.0	86.9	77.5	81.6
13.	Pendimethalin 0.86GR	97.5	90.5	90.0	95.0	84.0	82.7	81.0	78.2	84.4	87.0
14.	Dimension 0.10 GR	97.5	100.0	100.0	100.0	100.0	96.0	95.2	94.8	96.2	97.8
15.	Barricade 0.22 GR	97.5	95.2	90.0	95.0	97.0	96.0	94.3	93.9	93.1	94.7
16.	BAS051434H Drive 75DF	32.3	71.4	3.9	31.3	50.0	13.3	42.9	13.0	31.2	32.1
17.	BAS051434H Drive 75DF	12.3	4.8	18.9	31.3	30.0	20.0	28.6	8.6	21.8	19.6
18.	BAS 514 0.57GR	85.0	50.0	61.3	60.0	59.0	62.7	61.9	43.4	50.0	59.2
19.	BAS 514 0.57GR	12.3	33.3	6.4	0.0	14.9	6.7	14.3	0.0	0.0	7.4
20.	Pendimethalin 60WDG	100.0	97.6	93.8	95.0	90.0	97.3	94.3	94.8	93.1	95.1
21.	BAS051434H Drive 75DF	100.0	100.0	97.5	96.3	100.0	100.0	96.2	93.9	95.6	97.7
22.	BAS051434H Drive 75DF	100.0	100.0	98.8	100.0	94.0	96.0	87.6	89.6	92.5	95.4
23.	BAS 514 0.57GR	97.5	95.2	87.5	97.5	89.0	88.0	81.0	81.7	81.2	88.7
24.	BAS 514 0.57GR	77.4	54.8	62.5	68.8	65.0	62.7	47.6	30.4	34.3	55.9
25.	Dimension 1EC + NIS	82.5	83.3	88.8	96.3	89.0	92.0	84.8	93.9	93.1	89.3
26.	Dimension 1EC	95.0	92.9	83.8	93.8	93.0	90.7	81.9	73.9	77.5	86.9
27.	Dimension 0.164FG AND445	97.5	100.0	96.3	97.5	95.0	97.3	94.3	98.3	93.1	96.6
28.	Dithiopyr 1.06XF 98-025	50.0	52.4	73.8	37.6	64.0	52.0	70.5	64.3	62.5	58.5
29.	Dithiopyr 0.89XF 98-026	85.0	73.8	71.3	72.5	74.0	82.7	81.9	73.0	75.0	76.6
30.	Dithiopyr 2.20XF 98-029	92.5	90.5	67.5	78.8	64.0	73.3	66.7	65.2	65.6	73.8
31.	Dimension 40WP	95.0	88.1	86.3	86.3	88.0	90.7	84.8	82.6	84.4	87.3
32.	Fertilized control	59.9	57.1	25.1	37.6	50.0	46.7	47.6	21.7	40.6	42.9
	LSD0.05	43.5	49.1	37.8	35.0	35.5	34.6	28.0	36.7	30.0	31.8

¹These values represent reductions in percentage crabgrass cover per plot as compared with the untreated controls.

Initial applications (PRE) were made on April 29, Scott's (trt 2-9) sequential applications at 6 to 8 WAT on June 16, Dow (trt 10-15) sequential applications at 8 to 10 WAT on July 1, and BASF (trt 21-25) POST applications on July 1.

Table 6. The number of dandelions, oxalis, black medic, and percentage clover cover¹ in Kentucky bluegrass treated for the 1998 Pre- & Postemergent Annual Weed Control Study (data taken September 2).

		Counts				Percentage cover
	Material	Dandelion	Oxalis	Black Medic		Clover
1.	Untreated control	25.3	0.7	0.0		6.7
2.	S-8096	19.7	0.3	0.3		1.7
3.	S-8096	6.3	0.0	0.7		8.3
4.	S-8097	26.3	0.0	6.3		1.7
5.	S-8097	6.0	0.7	1.7		0.0
6.	S-8162	15.7	0.0	1.7		1.7
7.	S-8162	12.3	0.0	0.0		1.7
8.	S-8161	20.0	0.7	1.7		5.0
9.	S-8161	14.0	0.3	1.0		1.7
10.	Team Pro NAF-324 0.86GR	21.0	0.0	0.0		0.3
11.	Team Pro NAF-324 0.86GR	15.3	0.0	0.0		3.3
12.	Pendimethalin 0.86GR	14.0	0.0	1.0		8.7
13.	Pendimethalin 0.86GR	15.3	0.0	0.0		6.7
14.	Dimension 0.10 GR	12.7	0.0	1.0		0.0
15.	Barricade 0.22 GR	16.7	0.0	0.0		0.0
16.	BAS051434H Drive 75DF	15.0	2.3	0.0		0.3
17.	BAS051434H Drive 75DF	21.3	0.7	0.0		0.3
18.	BAS 514 0.57GR	16.7	0.7	0.0		0.0
19.	BAS 514 0.57GR	19.7	0.7	2.7		0.0
20.	Pendimethalin 60WDG	13.3	0.3	0.3		5.0
21.	BAS051434H Drive 75DF + MSO	1.7	1.0	0.0		0.0
22.	BAS051434H Drive 75DF + MSO	3.0	2.0	0.0		0.3
23.	BAS 514 0.57GR	1.7	0.7	1.0		0.0
24.	BAS 514 0.57GR	8.3	0.3	0.3		0.3
25.	Dimension 1EC + NIS	14.3	0.3	0.7		16.7
26.	Dimension 1EC	17.3	0.0	0.0		5.0
27.	Dimension 0.164FG AND445	24.7	0.3	2.0		0.0
28.	Dithiopyr 1.06XF 98-025	12.7	0.0	0.3		0.3
29.	Dithiopyr 0.89XF 98-026	14.0	0.0	0.0		10.0
30.	Dithiopyr 2.20XF 98-029	18.0	0.0	0.3		13.3
31.	Dimension 40WP	17.7	0.3	0.3		0.0
32.	Fertilized control	12.0	0.0	0.0		10.3
	LSD0.05	12.6	NS	2.6		NS