Group Title: CFREC-Apopka research report - Central Florida Research and Education Center-Apopka ; RH-93-1
Title: Fungicides to replace Benlate for some diseases of ornamentals
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 Material Information
Title: Fungicides to replace Benlate for some diseases of ornamentals
Series Title: CFREC-Apopka research report
Physical Description: 5 p. : ; 28 cm.
Language: English
Creator: Chase, A. R ( Ann Renee )
Central Florida Research and Education Center--Apopka
Publisher: University of Florida, IFAS, Central Florida Research and Education Center-Apopka
Place of Publication: Apopka FL
Publication Date: 1993
Subject: Plants, Ornamental -- Diseases and pests -- Control -- Florida   ( lcsh )
Fungicides -- Testing -- Florida   ( lcsh )
Plants, Ornamental -- Effect of pesticides on -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
Bibliography: Includes bibliographical references (p. 5).
Statement of Responsibility: A.R. Chase.
General Note: Caption title.
 Record Information
Bibliographic ID: UF00065847
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 70274009

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13 / Fungicides to Replace Benlate for some Diseases of Ornamentals
i-rs'i Scienc"
A. R. Chase'

University of Florida, IFAS, EP 3 0 1994
Central Florida Research and Education Center Apopka
CFREC-Apopka Research Report, RH-93-1 ,;-,sity of Florida

On September 11, 1991, Dupont deleted all ornamental uses from the Benlate 50W e,,~eg .
Due to its range of activity against plant pathogenic fungi and its broad label including all
ornamentals this fungicide was widely used for many diseases on ornamentals. Many growers have
faced the problem of replacing Benlate 50WP with another efficacious compound. There are a
number of potential candidates available for a replacement, but their spectrum of activity and/or
label restrictions make simple substitution impossible.

The most likely compound to fill the Benlate 50WP gap is thiophanate methyl. Thiophanate
methyl has the same mode of action as Benlate 50WP although the active ingredient differs. There
are currently a number of flowable and wettable powder formulations of thiophanate methyl:
Cleary's 3336 (flowable and wettable powder in prepackaged water soluble bags from Cleary's),
Domain FL (flowable from Grace-Sierra), Fungo 50WP wettablee powder from Grace-Sierra),
Systec 1998 (flowable from Regal), and Topsin M (flowable from Atochem).

In addition, there are a wide variety of other fungicides which could be used in place of
Benlate 50WP including both registered and experimental compounds. The following research was
conducted to fill some of the data gaps regarding the fungicides for diseases on a wide variety of
ornamentals caused byAltemaria, Cylindrocladium, Fusarium, Helminthosporium, powdery mildew,
Rhizoctonia, and Sclerotinia spp.. Specific fungicides, plants and diseases are given in the tables as
well as the results of the tests.


Benlate was never an appropriate choice for control of either Alternaria or
Helminthosporium leaf spot since it was not effective against these fungi. Since some growers used
Benlate for these diseases, a number of tests were performed. The tests summarized in Table 1
showed that the thiophanate methyl compounds also failed to give a significant level of control
(Fungo and Domain). Best disease control was consistently given with Chipco 26019, Daconil,
fluazinam (experimental compound) and Manzate. Terraguard and Domain gave a limited amount
of control in one trial. Phytotoxicity occurred in the Aechmea trial when plants were treated with

IProfessor of Plant Pathology, University of Florida, Central Florida Research and Education
Center Apopka, 2807 Binion Rd., Apopka, FL 32703. This work was supported in part through
grants from the following chemical companies: Ciba-Geigy Corporation, Elf-Atochem North
America, Grace-Sierra Crop Protection Company, ISK Biotech Corporation, Kincaid Enterprizes
Inc., Rhone Poulenc Ag Company, Rohm and Haas Company, Sandoz Agro, Inc., and Uniroyal
Chemical Company, Inc.

either Daconil or fluazinam.

Table 1.

Fungicides for Alternaria and Helminthosporium leafspot diseases.

Excellent Some
Disease Plant control control No control

Alternaria leaf spot Schefflera Chipco 26019 Fungo
Alternaria leaf spot Fatsia Daconil Domain
Helminthosporium leaf spot Aechmea Daconil Domain
(bromeliad) fluazinam Terraguard


Benlate was routinely used on a number of crops to control Cylindrocladium diseases.
Previous work has shown that Terraguard gives better control than alternatives for Cylindrocladium
root and petiole rot of Spathiphyllum. The winter test also showed that under lower disease
pressure all the thiophanate methyl compounds tested (Cleary, Domain and Systec) as well as
fluazinam (experimental compound) can give good disease control.

hL~ I aIj %.. I.-.y L iI I 4 UI111

Excellent Some
Disease Plant control control No control

Cylindrocladium Azalea Chipco 26019 bromuconazole
cutting rot Domain cyperconazole
Topsin M
Cylindrocladium Miniature Chipco 26019 Fungo
cutting rot rose fluazinam mycolubutanil
Terraneb Terraguard
Cylindrocladium Spathiphyllum Terraguard Cleary
petiole and root rot Domain

Tests with Cylindrocladium cutting rot on azaleas and miniature roses showed that many
compounds can give some disease control, although none were excellent. The experimental

Toln ,

compounds bromuconazole, cyperconazole, and myclobutanil did not give any measurable control
in these trials. Terraguard gave some control in one trial on azaleas but no control in the
miniature rose trial.


Fusarium diseases have long been targets for control with Benlate. Three tests were
performed to evaluate fungicides for control of Fusarium leaf spot on red-edge dracaena. The only
compound which did not give a significant degree of control was Terraguard. The thiophanate
methyl compounds gave some to excellent control depending on disease severity. Zyban is a
combination of thiophanate methyl and mancozeb (Manzate).

Tohl, "

C~lnn~;~fr Cr 1~lraiicrimn 1Pif cnrnt A~n flriiFann

=L tLlALl .1. =LV It,, U* JaLa..lf LtL ~= Jr.J ULLSL.J LI *I L ttL&,
Excellent control Some control No control

Domain Cleary Terraguard
Fungo Domain
Systec Topsin
Topsin Zyban


Although there are several fungicides which give better control of powdery mildew diseases
Benlate was used on some crops for this disease. Our test identified a number of compounds were
identified which gave excellent control of powdery mildew on gerber daisies, although many of
them also caused phytotoxicity. Funginex caused the most severe phytotoxicity, while myclobutanil
(experimental compound) was apparently safe at low rates but caused problems at the highest rates
tested. Very slight phytotoxicity was seen on plants treated with either bromuconazole
(experimental compound) or Chipco 26019. The two thiophanate methyl compounds (Fungo or
Topsin M) gave a lesser degree of control.

Table 4.

Fungicides for powdery mildew on Gerber daisy.

Excellent control Some control No control

bromuconazole Fungo Topsin M
Chipco 26019


Some of the Rhizoctonia diseases were easier to control than others. The easiest disease
to control was aerial blight of Boston fern. All of the chemicals tested gave excellent disease

control including the two thiophanate methyl compounds (Domain and Fungo). Damping-off of
China Doll seedlings was also controlled by Domain and Topsin M, but Terraclor and Terraguard
gave only moderate control of this Rhizoctonia disease. Stem rot of Impatiens was controlled with
four fungicides but again Terraclor and Terraguard gave a lesser degree of control. The pothos
trials showed a reversal with the best control achieved when Terraclor or Terraguard were used
and a lesser degree of control with the thiophanate methyl compounds (Cleary, Domain, Fungo,
Systec, and Topsin M).

Table 5.

Fungicide trials for Rhizoctonia diseases.

Plant. Excellent control Some control No control
Boston fern Carbamate
China doll Domain Terraclor
Topsin M Terraguard
Impatiens Chipco 26019 Terraclor
Domain Terraguard
Topsin M
Pittosporum Domain Terraneb
Pothos Terraclor Cleary
Terraguard Domain
Topsin M

The final trial was performed on aerial blight of pittosporum which is caused by a binucleate
type of Rhizoctonia (not R. solani). In this trial, Terraneb did not give any disease control, although
it gave excellent control of aerial blight of Boston fern which is caused by R. solani. Domain gave
excellent control of aerial blight of pittosporum.


One trial was performed for control of Sclerotinia blight. Manzate gave the best control
with Chipco 26019, Daconil, fluazinam (experimental compound), and myclobutanil (experimental
compound), also giving some disease control. Both Sentinel and Terraguard failed to give any
disease control in this trial.

Fungicide trials for Sclerotinia blight on Platycodon.

Excellent control Some control No control
Manzate Chipco 26019 Sentinel
Daconil Terraguard


These tests have established alternative fungicides which should effectively replace the use
of Benlate for many diseases of ornamentals. Since none of these compounds is broadly labeled
for all ornamentals, growers must consult labels to determine legal crops, rates and intervals for
use. The widespread interest of the chemical companies which market products for ornamentals
indicates that fungicides will continue to be available for control of our most serious diseases of
these crops.

Regardless of the pesticide or mixture of pesticides used, it is strongly recommended
that the effects be evaluated on a few plants, under your particular conditions before treating
all plants.
Mention of a commercial or proprietary product or a pesticide in this paper does not
constitute a recommendation by the authors, nor does it imply registration under FIFRA as


1. Chase, A.R. 1990. Phvtotoxicity of bactericides and fungicides on some ornamentals.
CFREC-A Research Report, RH-92-5.

2. Simone, G.W. and A.R. Chase. 1989. Disease control pesticides for foliage production
(Revision #4). Foliage Digest 12(9):1-8]

Table 6.

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