the ECM, where quackgrass dominated the veg-
biweekly with mefluidide at the recommended
etative cover, mefluidide controlled seedheads
rate and the other half was untreated. The turf in
better than imidazolinone and its effect was simi-
this area consisted of mixed stands of tall and fine
lar to the mowed control. The combination of the
fescue. Dry weights of the grasses harvested bi-
two PGRs also controlled seedhead development
weekly from this area were recorded after oven
drying at 70C for 48 hours.
at the ECM site. At the 5th Armored Division
sites, broadleaf weeds (knapweed) were unaf-
Analyses of variance of the data were per-
fected by the PGR treatments.
formed using CoStat (1990) version 4.20 (CoHort
Mefluidide at the recommended rate provided
Software). Least significant differences (LSD) were
the best control of foliar height (Table 2). The
calculated at 5%.
differences were greater for the Memorial Drive
sites than for the fine-fescue dominated Hospital
Lane location.
RESULTS
The effect of PGR treatment on turf color was
highly variable (Table 3). Color did improve with
1994 Experiments
time over the two rating dates of 9 June and 11
Data on the control of seedheads are shown in
August 1994.
Table 1. Tall fescue seedheads, which dominated
the unmowed plots of 5th Armored Division
Drive, were well controlled by PGR treatments
1995 Experiments
The plant height data collected for each loca-
except for the low rate of imidazolinone (one-
tion and PGR treatment are shown in Appendix
third of that recommended). Seedheads at Hospi-
tal Lane, dominated by the earlier-flowering fine
A. Since the differences between treatments were
fescue, were well controlled only by the recom-
similar at most sites, we used the means of the
individual treatments for each harvest date at
mended rate of mefluidide and by mowing. At
each site (Table 4). No differences
were noted after the first rating date
Table 1. Percentage seedhead control on 9 June 1994 at the
(17 May 1995), which was about 15 days
5th Armored Division Drive I, Hospital Lane and earth-
after the treatments were applied. This
covered magazine sites.
is probably related to the early effec-
5th Armored
tiveness of all PGR treatments. Differ-
Treatments
Div. Drive I Hospital Lane
ECM
ences between treatments became ap-
parent from the next rating date (30
1. Mefluidide, 2.3 L/ha
96.0
97.7
94.3
2. Mefluidide, 0.67 L/ha
95.3
6.0
95.0
May 1995) to the end of the rating pe-
3. Imidazolinone, 438 mL/ha
93.3
56.7
83.3
riod (25 July 1995). The results show
4. Imidazolinone, 136 mL/ha
38.3
21.7
7.0
that mefluidide at the recommended
5. Treatment 2 + 4
98.7
53.3
93.3
rate was statistically similar to the
6. Mowed check
99.7
100.0
99.0
mowed control in reducing plant
7. Unmowed check
1.0
21.7
0.3
height. The next best treatments were
Least significant
mefluidide at the low rate and the
difference at 0.05 level
mefluidide/imidazolinone combina-
of probability
27.4
27.8
20.8
tion. The imidazolinone treatment at
both rates studied did not control plant
Table 2. Foliar height on 10 June 1994 at three sites.
height as well as those treatments that
5th Armored
Memorial
Hospital
included mefluidide.
Treatments
Div. Drive II
Drive
Lane
Significant differences for plant
heights were also found between loca-
1. Mefluidide, 2.3 L/ha
14.7
10.6
10.0
2. Mefluidide, 0.67 L/ha
21.0
14.0
12.0
tions regardless of PGR treatment
3. Imidazolinone, 438 mL/ha
17.7
16.7
12.7
(Table 5). The differences in locations
4. Imidazolinone, 136 mL/ha
26.0
20.7
15.7
are probably due to the type of grasses
5. Treatment 2 + 4
16.0
14.0
14.3
growing at each location. The Hospital
6. Mowed check
5.0
5.0
5.0
Lane site has the shorter growing fine
7. Unmowed check
33.0
22.3
18.3
fescues and the other sites contain tall
Least significant
fescue and Kentucky bluegrasses along
difference at 0.05 level
with the fine fescues.
of probability
5.7
3.7
3.4
3
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