Group Title: CFREC-Apopka research report
Title: Fungicides for control of leaf spots of foliage plants, 1988
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Permanent Link: http://ufdc.ufl.edu/UF00065322/00001
 Material Information
Title: Fungicides for control of leaf spots of foliage plants, 1988
Series Title: CFREC-Apopka research report
Physical Description: 6 p. : ; 28 cm.
Language: English
Creator: Chase, A. R ( Ann Renee )
Central Florida Research and Education Center--Apopka
Publisher: University of Florida, Central Florida Research and Education Center-Apopka
Place of Publication: Apopka FL
Publication Date: 1988
 Subjects
Subject: Fungicides -- Testing -- Florida   ( lcsh )
Leaf spots -- Control -- Florida   ( lcsh )
Foliage plants -- Diseases and pests -- Control -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references (p. 6).
Statement of Responsibility: A.R. Chase.
General Note: Caption title.
 Record Information
Bibliographic ID: UF00065322
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 70152889

Full Text



Fungicides for control of leaf spots of foliage plants 1988

A. R. Chase1
IFAS, University of Florida
Central Florida Research and Education Center Apopka
CFREC-Apopka Research Report, RH-88-14

Fungicide trials are conducted on a continuing basis at the
CFREC-Apopka. Trials include many types of fungal diseases as well as
bacterial diseases. The following report summarizes trials conducted
during 1988 on fungal leaf spot diseases. Other reports summarize trials
on fungal root diseases (1, 2).
ALTERNARIA LEAF SPOT OF SCHEFFLERAS
Seedlings of Brassaia actinophylla (schefflera) and Schefflera
o arboricola (dwarf schefflera) were obtained from commercial producers and
planted in Vergro potting medium. Plants were grown on a raised bench
receiving a maximum of 2500 ft-c with temperatures between 75 and 950F.
Twelve single pot replicates of each plant type were used for each
fungicide treatment and for noninoculated and inoculated controls.
._ Fungicides were applied to runoff with a hand sprayer on 4, 12 and 19
7 April, 1988. Fungicide treatments were as follows: triazol fungicide
(Spotless 25WP at 0.3, 0.6, and 1.2 g/l), iprodione (Chipco 26019 50WP at
1.2 g/l), mancozeb (Manzate 200 80WP at 1.8 g/l), and benomyl (Benlate 50WP
at 1.2 g/l). Plants were inoculated on 6 April 1?88 with a spore
suspension of Alternaria panax adjusted to 1 x 10 spores/ml. Plants were
misted on a 5 sec/30 min 12 hr per day schedule starting the day of
inoculation. Number of lesions per plant was recorded on 21 April, 1988.
Both Manzate 200 and Chipco 26019 provided excellent disease control (Table
1). The lowest rate of Spotless also provided good disease control
although higher rates appeared to cause some phytotoxicity resulting in no
control of Alternaria leaf spot (Table 1).

Table 1. Efficacy of fungicides for control of Alternaria leaf spot of
scheffleras caused by Alternaria panax.

Number of lesions/planta
Brassaia Schefflera
Treatment Rate/literb actinophylla arboricola

Noninoculated control 0 aC 0 a
Inoculated control 15.7 c 14.5 b
Spotless 25WP 0.3 g 5.0 ab 12.1 b
Spotless 25WP 0.6 g 12.1 c 13.6 b
Spotless 25WP "1.2 g 14.6 c 21.1 c
Chipco 26019 50WP 1.2 g 0 a 0 a
Manzate 200 80WP 1.8 g 0 a 0 a
Benlate 50WP 1.2 g 9.2 bc 10.1 b

Mean number of lesions for 12 plants on 21 April 1988.
b Fungicides were applied on 4, 12 and 19 April 1988.
CNumbers in the same column followed by the same letter were not
significantly different at the 5% level (DNMRT).


1Professor of Plant Pathology. These studies were supported in part
through grants from Chevron Chemical Company, Fermenta Plant Protection,
and UniRoyal Chemical.






UKLCAn.-=r.Aa LCALIT &'J1U Ur L-AULMPAmA ANU 1IAKANJCA
Rooted cuttings of Calathea argentea 'Silver Portrait' and Maranta
leuconeura var. erythroneura (red maranta) were potted in Vergro medium.
Plants were grown under the conditions described above. Treatments
included noninoculated and inoculated control plants. Twelve single pot
replicates were used for each treatment. Fungicides employed on red
maranta were two formulations of chlorothalonil (Daconil 500F at 2.4 ml/l
and Daconil 90DG at 1.4 g/l). Fungicides employed for Silver Portrait we
as follows: triazol fungicide (Spotless 25WP at 0.3, 0.6, and 1.2 g/l),
mancozeb (Manzate 200 80WP at 1.8 g/l), and benomyl (Benlate 50WP at 1.2
g/1). For Silver Portrait fungicides were applied on 15, 22 and 29 June
with inoculation on 17 June. For red maranta fungicides were applied on
13, and 19 July with inoculation on 8 July 1988. Plants were inoculated
with a spore suspension of Drechslera setariae (=Helminthosporium setariaE
adjusted to 1 x 104 spores/in. The number of lesions were recorded on 1
July for Silver Portrait and 21 July for red maranta. Both Manzate 200 a]
Spotless provided excellent control of Drechslera leaf spot of Silver
Portrait when used at rates of 1.2 g/l (Table 2). Lower rates of Spotles!
did not provide as high a degree of disease control and Benlate provided
only slight control. In the trial on red maranta both formulations of
Daconil provided excellent disease control (Table 3).

Table 2. Efficacy of fungicides for control of Drechslera leaf spot of
Calathea argentea 'Silver Portrait' caused by Drechslera setariae.

Treatment Rate/litera Number of lesions/plantb

Noninoculated control 0 ac
Inoculated control 42.9 d
Spotless 25WP 0.3 g 13.8 b
Spotless 25WP 0.6 g 9.2 ab
Spotless 25WP 1.2 g 1.2 a
Manzate 200 80WP 1.8 g 0.7 a
Benlate 50DF 1.2 g 29.7 c
a Fungicides were applied on 15, 22 and 29 June 1988.
Mean number of lesions for 12 plants on 1 July 1988.
CNumbers in the same column followed by the same letter were not
significantly different at the 5% level (DNMRT).







'raDle i. trricacy or uaconll zormuiatlons ror controiing urecnsiera ieai
spot of Maranta leuconeura var. erythroneura caused by Drechslera
setariae and Fusarium leaf spot of Dracaena marginata caused by Fusarii
moniliforme.

Number of lesions/planta
Drechslera Fusarium
Treatment Rate/literb leaf spot leaf spot

Noninoculated control 0 aC 0 a
Inoculated control 9.9 b 12.9 b
Daconil 500F 2.4 ml 0.5 a 1.1 a
Daconil 90DG 1.4 g 0.4 a 1.4 a
aMean number of lesions for 12 plants on 21 July (red maranta) and 18 Jul)
b (red-edge dracaena).
Fungicides were applied on 6, 13, and 19 July 1988 for red maranta and or
27 June and 5 and 11 July 1988 for red-edge dracaena.
CNumbers in the same column followed by the same letter were not
significantly different at the 5% level (DNMRT).

FUSARIUM LEAF SPOI OF DRACAENA
Dracaena marginata (red-edge dracaena) were obtained from commercial
producers, planted in Vergro potting medium and grown under the condition;
described above. Twelve plants for each of the following treatments were
used: noninoculated control, inoculated control, chlorthalonil (Daconil
500F at 2.4 ml/I) and chlorothalonil (Daconil 90DG at 1.4 g/l). Plants
were sprayed on 27 June, and 5 and 11 July and inoculated with 2 x 106
spores of Fusarium moniliforme introduced into the plant whorl on 29 June
1988. The number of lesions was recorded on 18 July. Both formulations (
Daconil provided excellent control of this disease on red-edge dracaena
(Table 3).
RHIZOCTO IA AERIAL BLICGT OF BOSTON FERN
Two trials were conducted on Rhizoctonia aerial blight of Nephrolepi,
exaltata 'Compacta' (Boston fern). Plants were obtained from commercial
producers, established in Vergro potting medium and grown under the
conditions described above. Ten single plant replicates were used for ea(
of the following treatments in the first trial: noninoculated control,
inoculated control, triazol fungicide (Spotless 25WP at 0.3, 0.6, and 1.2
g/l), chlorothalonil formulations (Daconil 500F at 2.4 g/l and Daconil 901
at 1.4 g/l), ipenconazole (Award 10WP at 1.5 and 3.0 g/l), and
propiconazole (Banner 1.1E at 1.2 and 2.4 ml/1). Treatments were applied
on 22 and 28 June and 12 July and plants were inoculated on 24 June 1988.


- 3








icwzle 4. rrricacy or rung,
Nephrolepis exaltata 'C


[oninoculated 0 ad 1.0 a
noculated -- 9.5 b 1.0 a
laconil 500F 2.4 ml 0 a 1.0 a
iaconil 90DG 1.4 g 1.0 a 1.0 a


4-


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Table 5. Efficacy of different fungicides and timing intervals for contr
of aerial blight of Nephrolepis exaltata 'Compacta' caused by
Rhizoctonia solani AG4.

Rate/ Applications Disease
Treatment liter" per 4 wk period severityb

Noninoculated 0.5 ac
Inoculated 15.7 d
Terraclor 75W 0.3 g 3 7.0 abc
Terraclor 75W 0.3 g 4 10.6 bcd
Terraclor 75W 0.6 g 2 12.0 cd
Terraclor 75W 1.2 g 2 2.4 ab
Vitavax 75W 0.3 g 3 2.7 ab
Vitavax 75W 0.6 g 2 1.1 ab
G696 4F 0.4 ml 2 1.4 ab
G696 4F 0.8 ml 2 0.5 a
Terraguard 50W 0.3 g 2 2.1 ab
C2338 10EC 1.2 ml 2 4.2 abc
Benlate 50W 1.2 g 4 1.5 ab
Carbamate 76W 1.2 g 4 4.2 abc
Carbamate 76IW 1.2 g 4 2.0 ab
"Fungicides were applied on 3, 10, 17 and 24 August as required by each
treatment. All treatments were applied on 3 and 24 August.
Disease severity is a mean for 10 plants rated on 29 August for the
percentage of the foliage with symptoms of aerial blight.
Numbers in the same column followed by the same letter were not
significantly different at the 5% level (DNMF-).
This treatment was applied as a drench at the rate of 1 pint/ft2 of
surface area.

CONCLUSIOS
1. Alternaria leaf spot of scheffleras can be controlled best with
Chipco 26019 or Manzate 200. Spotless also provides some control
when used at 0.3 g/l (=0.25 lb/100 gal), but should not be used ,
higher rates since phytotoxicity may occur.
2. Drechslera leaf spot of calatheas and marantas can be controlled
with a variety of chemicals including Spotless, Manzate and
Daconil.
3. Fusarium leaf spot control on red-edge dracaena can be achieved
with Daconil.
4. Spotless and Daconil provide excellent, safe control of
Rhizoctonia aerial blight of Boston fern. Terraclor 75W provide;
good control only when used at 1 lb/100 gal rates. Vitavax 75W
provides good control at 0.25 to 0.5 lb/100 gal when applied
either 2 or 4 times per month. Terraguard 50W provided good
disease control at 0.25 lb/100 gal. Award and Banner should not
be used on Boston fern since they cause severe necrosis and
stunting of the foliage.




5 -








ITERATUME CITED
. Chase, A. R. 1988. Some new chemicals for control of Cylindrocladium
root and petiole rot of Spathiphyllum. CFREC-Apopka Research Report,
RH-88-11.
Chase, A. R. 1988. Chemicals for control of Pythium root rot 1988.
CFREC-Apopka Research Report, RH-88-13.
* Chase, A. R. and C. A. Conover. 1987. Temperature and potting medium
effects on growth of Boston fern infected with Rhizoctonia solani.
HortScience 22(1):65-67.




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