| Material Information
||Subdue 5S phytotoxicity on three foliage plants
||AREC-Apopka research report
||2, 2 p. : ; 28 cm.
||Chase, A. R ( Ann Renee )
Agricultural Research and Education Center (Apopka, Fla.)
||University of Florida, IFAS, Agricultural Research and Education Center-Apopka
||Place of Publication:
||Plants -- Effect of fungicides on -- Florida ( lcsh )
Foliage plants -- Diseases and pests -- Control -- Florida ( lcsh )
Fungicides -- Testing -- Florida ( lcsh )
||government publication (state, provincial, terriorial, dependent) ( marcgt )
bibliography ( marcgt )
non-fiction ( marcgt )
||Includes bibliographical references (p. 2).
||Statement of Responsibility:
||Florida Historical Agriculture and Rural Life
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Copyright 2005, Board of Trustees, University
SUBDUE 5S PHYTOTOXICITY ON THREE FOLIAGE PLANTS
A. R. Chase1
University of Florida, IFAS
Agricultural Research and EducationiCenter--- .-
AREC-Apopka Research Report RH-84-21_, .
Prior to labeling of the fungicide Subdue E (me~ xyl) j;j 1982,
several other formulations of metalaxyl were investigated. bnieof these
products, Subdue 5S (CGA 48988 5S, a soluble gra b+ wa, under inves-
tigation at this research center during the sum Tie~~g9792:/Tli follow g
report is a summary of work which was initiated by Dr. JT.--Knauss'Andl
completed during the following year concerning potential phytotoxicity of
Subdue 5S on three foliage plants.
The first experiment was performed using Peperomia obtusifolia and
was evaluated about three months after initiation. The treatments eval-
uated several soil drench fungicides used alone and in combination with
Subdue 5S (Table 1). Fresh weight of tops was recorded on 10-8-79. 2
Fungicide applications were made once using 1 1/2 pints of fluid per ft
of surface area as a drench. Benlate 50WP, Demosan 65WP and Fermate 86WP
were each safe on peperomia at the rates tested. Addition of Subdue 5S
to these fungicides did not significantly affect plant top weight compared
to use of each fungicide alone. Terraclor 75WP caused a significant reduc-
tion in top weight even when used at the low rate (3.4 g/gal = 0.75 lb/100
gal). When Subdue 5S was added to the Terraclor drench, the stunting ef-
fect of Terraclor was alleviated slightly. This may be due to a positive
growth response caused by Subdue 5S.
The second experiment tested effects of two rates of Subdue 5S applied
at 8 week intervals 1, 2 or 3 times. Dieffenbachia maculata (Perfection),
Peperomia obtusifolia, and Stromanthe amabilis (dragon tracks) were used
in this test. The rates of Subdue 5S tested represent 5 and 25 ppm ai
respectively (Table 2). Dieffenbachia height, number of side shoots, leaf
width, leaf length and number of leaves were unaffected by these treatments.
In contrast, top weight of peperomias was reduced slightly at the high rate
of Subdue 5S, but appeared unaffected by multiple applications (Table 2).
Number of new side shoots on dragon tracks was reduced on plants receiving
the higher rate of Subdue 5S more than once, but was unaffected at the lower
rate (Table 3). There were at least five more leaves on all plants treated
with Subdue 5S than on the non-treated control plants. This type of growth
response has also been noted in trials performed with Subdue 2E.
Subdue 5S was safely used on these foliage plants when applied at the
low rate of 5 ppm more than once and at the 25 ppm rate applied only once.
The recommended rate of Subdue 2E for foliage plants ranges from 9.4 to 37.4
ppm (0.5 to 2.0 oz/100 gal). Additions of Subdue 5S to other fungicides used
as drenches should be tested on each crop, but appears to be as safe as use
of the fungicide alone. The positive growth response commonly seen on plants
treated with the recommended rate of Subdue can sometimes counter the stunting
effects of other soil fungicides.
Associate Professor of Plant Pathology, Agricultural Research and Education
Center, 2807 Binion Road, Apopka, FL 32703.
Although comparisons between different formulations of a pesticide
are not always advisable, these results indicate the safety of combining
the liquid formulation of Subdue with other fungicides for soil drenches.
Combinations of Subdue 2E have been tried in numerous tests at this
research center and have been safe on the plants tested. Since each
growing condition is different each combination of pesticides should
be tested by the producer for safety on their crops. In addition, a
granular formulation of Subdue may be available in the future for use
on ornamental crops.
1. Anon. 1981. Subdue 2E. Florida Foliage 7(9):80.
2. Knauss, J. F. 1977. CGA-48988, A new systemic fungicide for control
of Phytophthora nicotianae var. parasitica on Peperomia obtusifolia.
Proc. Fla. State Hort. Soc. 90:330-332.
3. Knauss, J. F. 1979. Subdue, a new fungicide for the foliage plant
industry. Foliage Digest 2(4):12-14.
4. Powell, C. C. 1982. When using Subdue, use lower rate! Ohio State
Flower Grower's Hotline. 2(36):1.
5. Simone, G. W. 1981. Subdue 2E A new root disease control fungicide
for ornamentals. Florida Ornamental Growers Assoc. Newsletter 4(5):5-6.
6. Young, T. R., E. B. Seifried, and W. L. Brehn. 1977. Acylalanines, a
new class of systemic fungicides. Proc. Fla. State Hort. Soc. 90:
Table 1. Effect of Subdue 5S in combination with other
fungicides on top weight of Peperomia obtusifolia.
Treatment Concentration (g/gal) Mean top weight (g)
Control ---- 142.4da
Subdue 5S 1.9 133.0abcd
Benlate 50WP 2.3 137.5bcd
Subdue 5S 1.9 139.5cd
Benlate 50WP 2.3
Terraclor 75WP 3.4 123.4a
Subdue 5S 1.9 131.3abcd
Terraclor 75WP 3.4
Terraclor 75WP 6.8 127.4ab
Subdue 5S 1.9 129.3abc
Terraclor 75WP 6.8
Demosan 65WP 4.5 140.8cd
Subdue 5S 1.9 140.8cd
Demosan 65WP 4.5
Fermate 86WP 6.8 140.4cd
Subdue 5S 1.9 135.7bcd
Fermate 86WP 6.8
aNumbers in the same column followed by different letters
were significantly different at the 5% level using
Duncan's new multiple range test.
Table 2. Effect of different concentrations and number
of applications on top weight of Peperomia obtusifolia.
Concentration No. Mean top
Treatment (g/gal) applications weight (cm)
Control -- -- 175.5ba
Subdue 5S 0.4 1 168.3ab
Subdue 5S 0.4 2 164.0ab
Subdue 5S 0.4 3 172.2b
Subdue 5S 1.9 1 167.5ab
Subdue 5S 1.9 2 158.2a
Subdue 5S 1.9 3 161.4ab
aNumbers in the same column followed by
were significantly different at the 5%
Duncan's new multiple range test.
Effect of different concentrations and number of applications on
of new leaves and number of side shoots of Stromanthe-amabilis.
Treatment (g/gal) applications
. No. No.
.newTeaves 'new side shoots
NS = not significantly different.
Numbers in the same column followed by different letters were significantly
different at the 5% level using Duncan's new multiple range test.