Vol. 51—1997 - NorthEastern Weed Science Society

97
or Surflan at 1% i anti-transpiranti In the Spin Out / Surflan combinations, the Surflan was
simply added to t e Spin Out prior to application. Euonymus (Euonymus kiautschovicus Loes.),
forsythia (Forsyt . x intermediaZab.), and pyracantha plants growing in one gallon containers
were planted in th treated pots in a bark/peat medium. There were five pots of each treatment and
species and they ere maintained in a completely randomized design. On October 24, 1996 the
plants were rated or circling roots on the same scale used in the other studies.
RESULTS AND DISCUSSION
In the firs study, paint alone did not prevent circling roots or alter the growth of the
pyracantha (Tabl 1). All of the chemical treatments reduced circling roots compared to the
control, but the 10 est rate of Surflan allowed more circling than would be commercially
acceptable. The .25% rate of Surflan provided marginally acceptable control of circling roots.
All other treatme ts provided excellent control, with the 4.0% rate of Surflan being the only one
that provided to control.
The botto
the surface than
mostly covered
solubilizing the
s of the soil balls from all of the Surflan treated containers had no more roots on
e sides. The bottoms of the soil balls from the Spin Out treated containers were
th roots. It is possible that the bottom of the container stays moist longer,
pper and making it susceptible to leaching.
Regardle of treatment, all of the plants in treated containers were heavier than those in
containers that w re unpainted or had paint only. By killing root tips, the treatments may have
caused the devel ment of a more fibrous root system that absorbed nutrients and water more
efficiently than a oot system with a lot of circling roots.
The seco d study with the ryegrass and ajuga was initiated to determine how long the
treatments would remain effective. The ryegrass was planted one year after the containers had
been painted and he first crop had been grown in them. All of the chemically treated containers
provided good to excellent control of circling ryegrass roots (Table 2). Grass roots are known to
be especially se itive to Surflan, so after it was shown that the treatments were still active, the
grass plants and oil were discarded.
By Octo r 24, 1996, 18 months after the pots were treated, distinctive differences in root
development of t e ajuga were becoming apparent. All treatments still reduced circling roots
compared to the ontrol or paint alone (Table 2). However, the Spin Out and Surflan at 0.1% no
longer provided acceptable level of control. The Surflan at 0.25 and 0.5% still provided an
acceptable level f control, and at 2.0 and 4.0% allowed almost no circling roots.
Plants ar rarely grown in containers for more than two years. Treatments that last two
years will more t an adequately meet the needs of the nursery industry. They would also offer the
industry the opti n of keeping the treated container for reuse and shipping the finished plant in a
less expensive u treated container.
The othe study in 1996 demonstrated the variability that exists in species response to the
different treatme ts. One application of Spin Out provided good control of euonymus and
forsythia roots, t was weak on pyracantha (Table 3). Two applications controlled the roots of all
species. All rate of Surflan provided excellent control of pyracantha roots and good control of
euonymus roots. The 2.0% rate of Surflan provided marginally acceptable control of forsythia
roots, but the O. and 1.0% rates provided poor control. Surflan at 1.0% in anti-transpirant was
as effective as 1. % Surflan in paint for all species. Applying 1.0% Surflan in Spin Out reduced
the control of eu nymus and pyracantha roots below that provided by 1.0% Surflan in paint.
5 33 % Winter S eld. Rockland Corp., West Caldwell. NJ 07006