Group Title: AREC-A research report - Agricultural Research and Education Center-Apopka ; RH-86-8
Title: Control of Cylindrocladium root and petiole rot with Benlate 50WP
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Permanent Link: http://ufdc.ufl.edu/UF00065905/00001
 Material Information
Title: Control of Cylindrocladium root and petiole rot with Benlate 50WP
Series Title: AREC-Apopka research report
Physical Description: 6 p. : ; 28 cm.
Language: English
Creator: Chase, A. R ( Ann Renee )
Agricultural Research and Education Center (Apopka, Fla.)
Publisher: University of Florida, IFAS, Agricultural Research and Education Center-Apopka
Place of Publication: Apopka FL
Publication Date: 1986
 Subjects
Subject: Cylindrocladium -- Control -- Florida   ( lcsh )
Spathiphyllum -- Diseases and pests -- Control -- Florida   ( lcsh )
Fungal diseases of plants -- Control -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: A.R. Chase.
General Note: Caption title.
 Record Information
Bibliographic ID: UF00065905
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 70666372

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HISTORIC NOTE


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not reflect current scientific knowledge
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record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
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site maintained by the Florida
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Copyright 2005, Board of Trustees, University
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Il/L

Control of Cylindrocladium Root and Petiole Rot withBenlate 50WP

A. R. Chase1 ,il"l.'i Scienced
University of Florida, IFAS Library
Agricultural Research and Education Center Apopka
AREC-Apopka Research Report RH-86-8 O[T 14 gy987


A research program studying control of Cylindrocladium root and eft 4a
rot of Spathiphyllum spp. has been underway since 1980. Chemical,iUiutrt-na---
and environmental factors have been investigated over the past 5 years to
determine their role in disease expression. Several numbered compounds
(fungicides) became available for testing in 1984. In addition, several other
factors relating to efficacy of benomyl, currently the most effective
fungicide for this disease, were tested during this period and that
information is provided in this report.

All tests were performed on spathiphyllum plants obtained from commercial
producers. Plants were established in steam-treated potting medium consisting
of Canadian peat and pine bark (1:1, by volume) which was amended with 10 Ibs
Osmocote 19:6:12, 7 Ibs dolomite and 1 lb Micromax per cubic yard of medium.
Plants were maintained in a greenhouse receiving about 1500 ft-c natural light
and temperatures ranging from 60 to 95"F. Each test included noninoculated
and inoculated control treatments. Treatments were applied weekly for a total
of 7 to 11 weeks, depending upon the test. Drench volume was adjusted to
approximately 1 pt/ft Plants were inoculated with Cylindrocladium
spathiphylli one to three days after the first treatment application. Disease
severity was rated on a scale from 1 (no disease) to 5 (severe disease,
dead) weekly starting as the first symptoms developed and continuing until the
completion of the test. The tests performed can be divided into two
categories: 1) efficacy of benomyl (Benlate 50WP) as affected by addition of
another compound: and 2) efficacy of benomyl as affected by rate and holding
time before use.

1. Efficacy of Benlate 50WP as affected by addition of another compound. The
compounds included in these trials were both surfactants and disinfestants.
The first two tests were performed with the surfactant Aqua-Gro which was
added to two rates of Benlate (8 or 16 oz/100 gallons). Aqua-Gro was added at
the rate of 1 oz/100 gallons. When Aqua-Gro was used alone in the first trial
it did not provide any disease control, but in the second trial it provided
slight disease control (Table 1). This was probably due to increased
retention of water by the potting medium which decreased water stress for
plants treated with Aqua-Gro. There was no interaction between Aqua-Gro and
Benlate in either trial.


1Associate Professor of Plant Pathology, Agricultural Research and Education
Center, 2807 Binion Road, Apopka, FL 32703.








Similar trials were performed with Prevent, a quaternary ammonium compound
used for algae control on greenhouse surfaces. In both trials, Prevent provid-
ed a limited amount of disease control which was comparable to that obtained
with Benlate used alone (Table 2). The combination treatment of Benlate and
Prevent resulted in the highest level of disease control for both trials.
Prevent has been shown to reduce growth of several plant pathogens in the
laboratory and may have an effect in disease control in the greenhouse.

The final trial was conducted using both of the compounds previously
tested plus Physan (another quaternary ammonium compound used as a
disinfestant) and Ivory liquid soap. In this trial, none of the additives
provided disease control comparable to Benlate used alone (Table 3).
Similarly, when these compounds were added to Benlate, the level of disease
control was not improved. It appears that addition of these products can
influence efficacy of Benlate under some conditions, but not others. The lack
of benefit in use of Prevent in this trial is probably due to the decreased
rate of the product in the second test (0.13 gal/100 gallons compared to 0.52
gal/100 gallons). Of the compounds included, Prevent did give the best
disease control for a single product following that for Benlate.

2. Efficacy of Benlate 50WP as affected by rate and holding time before use.
Benlate was prepared at the rate of 8 oz/100 gallons and held for various
periods of time prior to application (Table 4). Over a period of 8 weeks
Benlate was as effective after holding for up to 72 hours as it was when used
freshly prepared (Table 4). The pH of the Benlate solution was measured prior
to each use and was found to remain between 7.12 and 7.14 for the 3-day period
each week.

A trial was also conducted using higher rates of Benlate to determine
potential for phytotoxicity and possible eradication of the pathogen. Rates
of 1, 2, and 4 lbs/100 gallons were applied weekly for a total of 8 weeks
starting on 10-18-84. Disease severity was significantly affected by the
amount of Benlate added with ratings of 4.0, 1.9, 1.2, and 1.0 for 0, 1, 2,
and 4 Ibs Benlate per 100 gallons, respectively. However, severe
phytotoxicity resulted when Benlate was used at the 2-or 4-1b rate and was
expressed as marginal chlorosis and necrosis which initially appeared gray and
turned tan with age.

Conclusions

In general the following conclusions can be drawn from the tests
reported here.

1. Addition of Prevent at the rate of 0.52 gallons/100 gallons of
a Benlate 50WP drench solution gives improved disease control
compared to use of Benlate alone.

2. A solution of Benlate 50WP (8 oz/100 gallons) can be maintained
under greenhouse conditions (60 95"F) for 72 hours without a
decrease in efficacy.

3. Benlate should not be applied to spathiphyllum at rates of 2
lbs/100 gallons or higher since severe phytotoxicity develops on
treated plants and use at this rate is illegal.








Table 1. Effect of adding Aqua-Gro to Benlate 50WP for the control of
Cylindrocladium root and petiole rot of spathiphyllum.


Mean disease severity rating
Rate per
Treatmenta 100 gallons Test 1c Test 2

Noninoculated -- 1.0 ad 1.0 a

Inoculated -- 5.0 c 3.9 c

Benlate 0.5 lb 3.4 b 1.1 a

Benlate 1.0 lb 1.8 a 1.0 a

Benlate and 0.5 lb 3.0 b 1.5 a
Aqua-Gro 1.0 oz

Benlate and 1.0 lb 1.8 a 1.1 a
Aqua-Gro 1.0 oz

Aqua-Gro 1.0 oz 5.0 c 2.9 b
plants were drenched at the rate of 1 pt/ft2 weekly starting on
10-12-84 (Test 1) or 12-6-84 (Test 2) for a total of eight weeks.

bMean rating for ten replicates according to the following scale:
1 = no disease, 2 = 1-25% diseased, 3 = 26-50% diseased, 4 =
51-75% diseased, and 5 = 76-100% diseased, usually dead.
CTest 1 plants were inoculated on 10-15-84 and rated on 11-21-84 and
Test 2 plants were inoculated on 12-10-84 and rated on 1-31-85.
dNumbers in the same column followed by the same letter were not
significantly different at P=0.05 (Duncan's new multiple range test).








Table 2. Effect of Prevent and Benlate 50WP mixtures on severity of
Cylindrocladium root and petiole rot of spathiphyllum.


Trea tmen ta

Noninoculated

Inoculated

Prevent

Prevent

Benlate 50WP

Prevent and
Benlate 50WP

Prevent and
Benlate 50WP


Rate per
100 gallons
--


0.52

1.56

0.5

0.52
0.5

1.56
0.5


Mean disease severity ratingb

Test 1c Test 2

1.0 ad 1.0 a

3.7 d 3.6 c

3.0 c 2.4 b

3.2 cd 2.2 b

2.8 c 1.8 b

1.6 b 1.3 a


1.6 b


2.0 b


plants drenched at the rate of 1 pt/ft2 weekly starting on 10-8-84
(Test 1) or 12-6-84 (Test 2) for a total of 8 weeks.
bMean severity rating for 10 replicates based on the following scale:
1 = no disease, 2 = 1-25% diseased, 3 = 26-50% diseased, 4 = 51-75%
diseased, and 5 = 76-100% diseased, usually dead.
cTest 1 plants were inoculated on 10-9-84 and rated on 11-21-84 and
Test 2 plants were inoculated on 12-10-84 and rated on 2-20-85.
dNumbers in the same column followed by the same letter were not
significantly different at P=0.01 (Duncan's new multiple range test).









Table 3. Effect of spray additives on efficacy of Benlate 50WP in
controlling Cylindrocladium root and petiole rot of spathiphyllum.

Rate per
Treatment 100 gallons Mean disease severity rating


Noninoculated -- 1.1 ac
control

Inoculated -- 3.9 c
control

Benlate 50WP 0.5 lb 1.5 a

Aqua-Gro 1.06 pt 3.3 bc

Physan 1.06 pt 3.4 bc

Prevent 1.06 pt 2.7 b

Ivory soap 1.06 pt 3.6 c

Benlate 50WP and 0.5 lb 1.2 a
Aqua-Gro 1.06 pt

Benlate 50WP and '0.5 lb 1.1 a
Physan 1.06 pt

Benlate 50WP and 0.5 lb 1.0 a
Prevent 1.06 pt

Benlate 50WP and 0.5 lb 1.6 a
Ivory soap 1.06 pt


plants were drenched at the rate of 1 pt/ft weekly starting on 2-7-85
for a total of 10 applications.
bMean rating for ten replicates according to the following scale: 1 = no
disease, 2 = 1-25% diseased, 3 = 26-50% diseased, 4 = 51-75% diseased,
and 5 = 76-100% diseased, usually dead.
CPlants were inoculated on 2-8-85 and rated on 4-11-85. Numbers in the
same column followed by the same letter were not significantly different
at P=0.05 (Duncan's new multiple range test).









Table 4. Effect of storing a solution of Benlate 50WP on efficacy in
controlling Cylindrocladium root and petiole rot of spathiphyllum.


Mean disease severity rating
Treatmenta 4-11-85 4-18-85


Noninoculated control 1.0 ad 1.0 a

Inoculated control 3.1 b 3.2 c

Fresh solution 1.4 a 1.6 ab

Stored 1 hour 1.2 a 1.5 ab

Stored 2 hours 1.5 a 1.6 ab

Stored 4 hours 1.0 a 1.4 ab

Stored 8 hours 1.4 a 1.5 ab

Stored 24 hours 1.7 a 1.9 b

Stored 48 hours 1.5 a 1.8 ab

Stored 72 hours- 1.2 a 1.4 ab

plants were drenched at the rate of 1 pt/ft2 weekly starting on
2-19-85 for a total of 9 applications. Benlate was used at the rate
of 8 oz/100 gallons.
bMean rating for ten replicates according to the following scale: 1 =
no disease, 2 = 1-25% diseased, 3 = 26-50% diseased, 4 = 51-75%
diseased, and 5 = 76-100% diseased, usually dead.
CPlants were inoculated on 2-18-85 and rated as indicated.

dNumbers in the same column followed by the same letter were not
significantly different at P=0.05 (Duncan's new multiple range test).




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