Vol. 15—1961 - NorthEastern Weed Science Society

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135.
Dim tro for Weed Control
in Gladiolus
Arthur :Bing*
Weed control investigations on gladiolus have been in progress for
several years on Long Island and the results have been reported to this
conference (1, 2, 3). Diuron gives long lasting weed control and suppresses
or eliminates a wide variety of weeds. However, Diuron may slightly del8\Y
blooming or reduce cut nower yield (3). Simazine also ma.y adversely affect
cut flower yield (3). Diuron and Simazine usually give good weed control
on stock grown for corms without reducing corm yield. CIPC gives good
temporary control of weeds other than the resistant Jweeds such as galinsoga,
ragweed, or perennial grasses. Liquid Dinitro has proved to be an effective
pre emergence herbicide at ra.tes of 4-12 pounds actual DliBPper acre. It
can be used on emerged weeds but should be kept off of gladiolus foliage.
The past two seasons a series of tests were made to determine how safe
the DNBPapplications are to gladiblus. Also a test was carried out
to evaluate the feasibility of a second application of granular DNBPto
gladiolus in spiking or prespiking stage. Results in 1959 (3) showed that
the application of liquid DliBPat 4,8, and 12 pounds actual DNBPin 100
gallons of water per acre did not reduce corm yield of variety Friendship
in numbers or weight compared to hand weeded cultivated plots. There was a
slight del8\Y in flowering but no loss in cut flowers as measured by numbers
or weight of flowers cut. The 1959 corms from each treatment were planted
in the same plot areas in 1960and received the same treatments. Flowering
again was not adversely affected by the treatment.
On June 14, 1960a half acre of gladiolus was planted as part of a
virus transmission study. After the small corms were set in the furrows,
the corms were covered by running a tractor cultivator over the rows.
Immediately after covering, the half acre was spr8\Yed with one gallon of DNBP
(3 pounds per gallon) in 18 gallons of water. This kept the field free of
weeds for about 5 weeks. After 7 weeks the field was cultivated and the
rows hand weeded where necessary. Only a few weeds were present. In a few
days as spikes began to emerge the rows were treated With a 2 foot wide band
of 10~ granular DNBPat 6 pounds DNBPper acre. Flowering was normal in
early September. In late October a good crop of corms was dug. trleed control
in the rows was good -.until the time of digging_
The suggested treatment is liquid
emergence followed by cultivation at
of granular DliBPat 4-6 pounds actual
the
per
DNBPat 6-8 pounds per acre
pre-spike stage and then an before
application
acre;
* Cornell Ornamentals Research Laboratory, Farmingdale, Long Island, New York