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Copyright 2005, Board of Trustees, University
HERBICIDES AND THE FOLIAGE INDUSTRY --
I. STOCK BEDS HUME LIRAF
By AUG 2 7 197
R. T. Poole, Will E. Waters and A. J. Pate
Agricultural Research Center i
Apopka, Florida .AS
Mimeo'Report ARC-A 1972-1 *
Producers of tropical foliage plants maintain stock beds for several
years in the same place as sources of propagating material and cuttings are
harvested periodically for propagation. Normally stock plantings form a
dense protective mat over the ground that reduces weed introduction and
competition. However, weeds frequently become a major problem through
encroachment after initial planting or after propagating materials have been
removed and costly hand labor is now the principal method of weed control.
Safe and effective herbicides applied to the beds after planting and after
harvest would greatly benefit the foliage plant industry.
Philodendron oxycardium (Cordatum), Dieffenbachia picta 'Exotica'
and Syngonium podophyllum 'Nephthytis Green Gold' were planted in ground
beds February 23, 1970. Herbicides were applied May 6, July 24 and October
19, 1970 and yield of stock plants was recorded periodically. The experi-
ment was terminated March 12, 1971.
June 1, 1971 a second experiment was initiated which included
'Cordatum', 'Nephthytis Green Gold' and 'Exotica' plus Cordyline terminilis
'Baby Doll' and Rhaphidophora aurea 'Golden Pothos'. Portions of this
experiment are still in progress.
Rooted cuttings of the above mentioned plants were transplanted into
ground beds of Lakeland fine sand amended with 2 inches of peat. The beds
were located under 80% shade in a slat shed covered with 2 mil polyethylene
and heated during the cold months. Plants were fertilized with 13-6-12
Osmocote at 2000 ppa at 6 month intervals and supplemented with liquid feed.
Data obtained included weed control, crop tolerance, yield and rooting
response, yield data collected included fresh weight, length and number of
nodes. Data was compared to control and expressed as percent of control.
Herbicides, formulations, manufacturers and amounts of herbicides
used in the tests are listed in Table 1. Plants tested for herbicide
tolerance are listed in Table 2.
Weight of CORDATUM was not appreciably affected by herbicides except
for Eptam at 6 pounds active ingredient per acre (ai/A) and Amiben at 4 pounds
ai/A (Tables 3 and 4).
Herbicides which did not reduce weight of NEPHTHYTIS were Dacthal-
CIPC, Planavin, Treflan,GS-13638 and MC 4379 (Tables 3 and 4).
Yield responses from DIEFFENBACHIA EXOTICA to herbicides differed
greatly between 1970 and 1971. Only GS-13638 appeared satisfactory in
1970, however, in 1971, only Princep reduced yield slightly (Tables 3 and 4).
All herbicides used in Exp. 2 appeared safe for use on GOLDEN POTHOS
(Table 4). All herbicides used in Exp. 2, except possibly MC 4379, appeared
satisfactory for use on BABY DOLL (Table 4).
MC 4379 caused necrosis of young leaves of most plants tested 2-3
days after application. However, new growth was unaffected and yield
was not appreciably reduced (Table 4).
Weeds were not present in sufficient number during 1970 to evaluate
herbicidel effectiveness on weeds. However, weed control was evaluated
during 1971 and all herbicides gave adequate weed control with the possible
exception of Dacthal (Table 5). The major weed species present in the
experimental area were Richardia scabra (Florida Purslane), Cyperus
compressus (Water sedge), Digitaria sanguinalis (Crabgrass) and Amaranthus
Some cuttings taken from stock beds treated with herbicides were
propagated to determine the effect of herbicides on subsequent rooting.
Herbicides apparently had no effect on rooting of cuttings (Table 6).
Although further research needs to be conducted on previously tested
herbicides as well as additional herbicides, producers of foliage plants
may wish to try, on an experimental basis for themselves, some herbicides.
Data from these two experiments indicate that commercially available
herbicides which may be used effectively with little or no reduction in
yield or leaf damage on a variety of foliage plants are: Planavin at
rates up to 3 pounds active ingredient per acre (ai/A) and Treflan, 4'
pounds ai/A. Princep treated plots possibly would have produced higher
yields if the herbicides was applied less frequently.
Before using a herbicide the grower should read carefully all
instructions relating to the herbicide and use the herbicide on a small
experimental plot before treating a large area. Only the recommended
rate should be applied because larger rates may severely reduce growth of
Herbicides used in this research are pre-emergent herbicides which,
at recommended rates, have little tS no effect on weeds already established.
To be most effective they should be applied immediately after removal of
weeds. A satisfactory procedure to follow is to harvest the cuttings,
remove all weeds and apply the herbicide. Irrigation (?f inch) immediately
following herbicide application will reduce toxicity and improve effect-
iveness of the herbicide.
CAUTION. The above results are obtained from ground beds that have
been treated for one year in Exp. 1 and 6 months in Exp. 2. Repeated
applications of herbicides may cause an increase of the herbicide in the
soil and reduced yield of the crop.
MENTION OF A MATERIAL DOES NOT IMPLY ANY GUARANTEE OF EFFECTIVE-
NESS OR SAFETY. SPECIFIC TRADE NAMES USED DOES NOT IMPLY ENDORSEMENT OR
PREFERENCE OF THESE COMPOUNDS OVER EQUIVALENT COMPOUNDS.
Table 1. Nomenclature, formulations, manufacturer and rates
tested on foliage plants.
Trade names Common Pounds Material
and formulations name* Manufacturer ai/A per acre
Amiben 23.4 EC amiben Amchem 4 2.0 gals
AAtrex 80 WP atrazine Giegy 2 2.5 Ibs
Dacthal 75 WP DCPA Diamond 12 16 lbs
Eptam 89.5 EF EPTC Stauffer 6 0.9 gals
GS-13638 50 WP GS-13638 Giegy 4 8.0 Ibs
MC-4379 21 EC MC-4379 Mobil 1.5 0.8 gals
Planavin 75 WP nitralin Shell 3 4.0 Ibs
Princep 4 G simazine Giegy 2 50 Ibs
Telvar 30 WP monuron Dupont 3 3.8 Ibs
Treflan 44.5 EC trifluralin Elanco 4 1.0 gal
Common names accepted by the Terminology Committee of the Weed Science
Society of America.
Table 2. Plants tested for
Green Gold Nephthytis
Table 3. Yield (% control) from stock beds treated with
herbicides May 6, July 24 and October 19, 1970.
Herbicide ai/A Cordatum Nephthytis Exotica
.5 101 114
Yield (% control) of 3tock beds treated with herbicides June
10 and September 13, L971. Experiment 2.
Herbicide ai/A Cordatum Nephthytis Exotica Pothos Baby Doll
Control 100 :00 100 100 100
Princep 2 103 85 86 94 100
GS 13638 4 106 :10 93 90 103
Treflan 4 97 105 106 108 96
Planavin 3 97 107 104 125 103
Dacthal 12 101 .19 109 105 103
MC 4379 1.5 101 .02 102 103 78
Table 5. Weed control (%) in foliage
Herbicides applied June 10,
13, 1971. Experiment 2.
Herbicide ai/A Aug 3 Dec 12
Control 0 0
Princep 4 G 2 79 73
GS-1363~ 50 WP 4 74. 83
Treflan 44.5 EC 4 87 73
Planavin 75 WP 3 88 65
Dacthal 75 WP 12 55 47
MC-4379 21 EC 1.5 79 78
Table 6. Rooting grade of cuttings. Stock
beds sprayed May 6, 1970. Cuttings
taken July 17. Graded August 14.
Herbicide ai/A Nephthytis Cordatum
Control 2.6 3.4
Dacthal-CIPC 6-1.5 2.8 3.2
Planavin 4 2.. 7 3.0
Princep 2 2.1 3.2
AAtrex 2 2.9 3.3
Telvar 3 2.8 3.3
Treflan 4 2.5 3.0
Eptam 6 2.6 3.1
Amiben 4 2.7 3.1
GS 13638 3 2.3 3.0 -
12 a no roots. 4 heay rooting,