Vol. 15—1961 - NorthEastern Weed Science Society

PJ,OORESSREPORT:ON.:WEEJhCGNTROL IN NUJtSERYCROPSI
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.... 'John··R.;'Havis2
137.
The Massachusetts nurseryman has weed problema in two general situations,
the lining-out bed and the field. The weed problem in the lining-out bed 1s
often most serious the year that the small aeadltnS8 or rooted cuttings are
set, usually 6 to 9 inches apart in beds 4to 6 feet wide. The second year
the weed problem may be reduced by shading the IOU by the plants themselves.
o
Nurserymen also are interested in control of annual weeds and grasses in
the field. Quackgrass is a problem for most nurseries in the State,- more of
a problem for some than for others. Where quack has become widespread in the
nursery no other weed problem seems important in comparison.
This is a repartof two years work on weed problems in the nursery: annual
weeds in established plants in the field; quackgrass in field stock; and annual
weeds in the lining-out beda. The work on each problem is reported separately.
FALL APPLICATIONOF TRlAZINES FOR ANNUALWEEDS
Trials of chemicals for control of annual weeds in the nursery have been
conducted in Massachusetts for about 10 years, but not until the advent of
simaztne~have the nurserymen become very much interested. Experimental results
at Waltnim·had shown repeatedly that simazine at 2 Ib.tA applied in Mayfollowing
cle"tifcultivation held annual weed. until about the first of August. Four
pounds3~ld the field weed-free for the season. This did not appear to solve
_. the probl~ entirely because many nur.e~ymen were so busy digging for sales
and-doing landscape jobs in the spring'that when they could spare the time for
the fields weeds had taken over. Usually, more time was available in late
summerand fall. Interest was expressed in fall treatments that would check
the growth of spring weeds until late Mayor June. Full season control was not
necessary.
A few nurseries "in Massachusetts have made trial applications of simazine
in late summeror fall for control of annu~1 weeds the following spring. Weed
control bas been generally good, lasting to about June I or'even Aug1Jstor
." .... ,-". .. ._ .• 1..
September. Injury to some plants has beed observed, e.g. Azalea, Rhododendron,
!!!! crenate convexa, Pinus thunbersi, Euonxmusradickns, Picea glauca, and
Picea glauca dena.ca. Exact rates of application were difficult to determine
from the grower applications, but most of the injury appeared to have resulted
from rates of 4 tb.tA or higher.
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A replicated experiment was set up in the fall of 1959 on es~abl1shed
Rhododendron roseum elegant (12"-14 1t hlgh) an~.EuonI.!'!!s J:ad1cans yesetus
(8"-10 11 spread) at Waltham on fine sandy loa_soU. SiDWi~~ne, :ati'azine,
and propazine were applied October 23, 1959{ as sprays over'·weed#· consisting
mainly of chickweed, henbit, and annual bluegras's. Eacb plop'aontained
12 plants of each species, and treatments were :repllcated dit~e times.
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Contribution Number 1280 Massachusetts Agricultural Experiment Station
2aead, Waltham Field Station, University of Massachusetts, Waltham