the Fate of Field Paspalum Control - The Paginator

TURF TALK • continued
It is important to note that the effectiveness of Tenacity and
Tupersan in controlling field paspalum preemergence from
seed in mature turfgrass stands is unknown.
Fusilade II label. The label also states
that the application rate for Fusilade
II to tall fescue “should be” 5 to 6 oz.
product/A. The label further states
that tall fescue may be injured but
should recover in 10 to 14 days.
In these studies, Fusilade II was
applied at 24 oz. product/A (i.e., 0.375
lb. ai/A), which is four times the high
label use rate for tall fescue. No injury
was noted in the unimproved site
(mostly Kentucky bluegrass and perennial
ryegrass) with Fusilade II and
other herbicides. This was attributed
to the tall, dense field paspalum canopy,
which likely intercepted most of
the herbicide before it could reach
the underlying turf. It was observed,
however, that this very high rate of
Fusilade II injured tall fescue in the
2010 study for a period of about 35
to 40 days, but the turf eventually
recovered. The injury took the form of
browning and stunting of leaves, as
well as some thinning of the tall fescue
stand. In unrelated UM studies, it was
found that hard fescue showed no
signs of injury from the same high
Fusilade II rate used in this study.
Results from the 2010 study also
suggest that the mix of Velocity +
Dismiss is another candidate for future
study. This mix also reduced tall fescue
quality for about 30 days. Hence,
future research needs to focus on
lower use rates and perhaps more
frequent applications of these herbicides
to maximize their effectiveness
while minimizing injury to tall fescue.
Another key finding was that
Tenacity and Tupersan reduced field
paspalum populations significantly
when applied preemergence to springseeded
stands of tall fescue, perennial
ryegrass and hard fescue. Many field
paspalum seedlings, however, escaped
and were problematic in the springseeded
stands. The level of control
was poorest in hard fescue. This was
attributed to the slower development
of hard fescue, which did not compete
as effectively with field paspalum as
did the more rapidly developing tall
fescue and perennial ryegrass seedlings.
Numerically, lowest field
paspalum cover ratings were observed
in Tupersan-treated plots. Regardless,
it would be helpful to use either
Tupersan or Tenacity in the seedbed
when renovating turfs that were previously
contaminated by field paspalum.
It is important to note that the
effectiveness of Tenacity and Tupersan
in controlling field paspalum preemergence
from seed in mature turfgrass
stands is unknown. In unrelated
UM studies, however, it is been well
established that Tenacity and Tupersan
generally perform poorly in controlling
crabgrass (Digitaria spp) preemergence
in mature turf stands, and thus, it is
likely that this would be also true of
field paspalum. •
14 MTC TURF NEWS