1999 Iowa Turfgrass Research Report

The efficacy of Trimec experimental formulations in the control of ground ivy (creeping charlie) was examined in this study. It was conducted at Veenker Memorial Golf Course, Ames IA, in a common bluegrass and perennial ryegrass area heavily infested with ground ivy. The soil in this area was a Nicollet (fine-loamy, mixed, mesic Aquic Hapludoll) with 7.0% organic matter, 56 ppm P, 368 ppm K, and a pH of 7.2.

The study was designed as a randomized complete block. Individual plot size was 5 x 5 ft with three replications. A pretreatment survey of the area showed the presence of ground ivy in each of the individual plots. There were seven Trimec experimental treatments plus an untreated control. Trimec Classic was applied at 1.5 fl oz/1000 ft² and NB20680 (substituted for EH1349), NB 30137, NB30138, NB30139, NB30140, and NB30141 were applied at 3.0 fl oz/1000 ft² (Table 2).

Applications were made postemergently on July 14, 1998 after ground ivy was established. A carbon dioxide backpack sprayer equipped with Teejetâ #8006 flat fan nozzles at 30 psi was used. The materials were diluted into 90 ml of water. This translates to a rate of 1 gallon/1000 ft².

Ground ivy control evaluations were made on July 21, July 30, August 6, and August 12. Control was assessed as the percentage of living ground ivy per individual plot.

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

No phytotoxicity was observed in any treated turf. On July 21, treated ground ivy exhibited different degrees of damage and symptoms (Table 1).

All materials significantly reduced ground ivy populations (Table 2). Some of the materials worked faster than others. On July 21, virtually all of the ground ivy was dead in turf treated with NB30141 and slightly less mortality was observed in turf treated with NB20680, NB30139, and NB30140. By August 6, all of experimental materials had killed at least 95% of the ground ivy (Table 3).

Table 1. Ground ivy damage and phytotoxic symptoms observed on July 21.

REP 1
1	2	3	4	5	6
NB30141   dead plants	NB30139   dead plants	NB20680   dead plants	Trimec Classic   plants curled & collapsed	Untreated   no damage	NB30138   plants curled
		REP 2
7	8	1	2	3	4
NB30140   dead plants	NB30137   dead plants	NB20680   dead plants	NB30138   dead plants	Untreated   no damage	NB30137   dead plants
				REP 3
5	6	7	8	1
NB30140   dead plants	NB30139   burnt leaves	Trimec Classic   plants curled	NB30141   dead plants	NB30137   burnt leaves

2	3	4	5	6	7	8
NB30140   dead plants	Trimec Classic   plants curled	NB30139   dead plants	NB30138   dead plants	NB30141   dead plants	NB20680   plants collapsed	Untreated   no damage

Table 2. Percentage living ground ivy cover in turf plots of the 1998 PBI Gordon Ground Ivy Study.

	Materials	Rate [fl oz] product /1000 ft2	July 21	July 30	August 6	August 12	Mean
			__________________________ %___________________________
1.	Untreated control	NA	63.3	60.0	65.0	66.7	63.8
2.	NB20680 ***	3.0	5.7	2.3	1.7	0.3	2.5
3.	NB30137	3.0	11.0	3.0	2.7	5.7	5.6
4.	NB30138	3.0	11.3	3.3	0.7	1.7	4.3
5.	NB30139	3.0	5.7	2.3	1.0	1.0	2.5
6.	NB30140	3.0	5.7	6.0	1.0	1.0	3.4
7.	NB30141	3.0	1.0	1.7	2.0	0.7	1.3
8.	Trimec Classic	1.5	58.3	18.3	20.0	8.0	26.2
	LSD0.05		19.9	9.7	17.8	11.4	12.8

**NB20680 used instead of EH1349.

Table 3. Percentage reduction in living ground ivy cover¹ in turf plots of the 1998 PBI Gordon Ground Ivy Study.

	Materials	July 21	July 30	August 6	August 12	Mean
		_____________________________ % _____________________________
1.	Untreated control	0.0	0.0	0.0	0.0	0.0
2.	NB20680 ***	91.0	96.1	97.4	99.5	96.1
3.	NB30137	82.6	95.0	95.9	91.5	91.2
4.	NB30138	82.1	94.4	99.0	97.5	93.3
5.	NB30139	91.0	96.1	98.5	98.5	96.1
6.	NB30140	91.0	90.0	98.5	98.5	94.6
7.	NB30141	98.4	97.2	96.9	99.0	97.9
8.	Trimec Classic	7.8	69.4	69.2	88.0	59.0
	LSD0.05	31.5	16.2	27.4	17.1	20.0

¹These values represent reductions in living ground ivy cover as compared with the untreated controls.

ISU Horticulture:Publications:1999 Turfgrass Report

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