Group Title: AREC-A research report - Agricultural Research and Education Center-Apopka ; RH-86-9
Title: Some new compounds for control of Cylindrocladium root and petiole rot of Spathiphyllum
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Permanent Link: http://ufdc.ufl.edu/UF00065906/00001
 Material Information
Title: Some new compounds for control of Cylindrocladium root and petiole rot of Spathiphyllum
Series Title: AREC-Apopka research report
Physical Description: 12 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: Fungal diseases of plants -- Control -- Florida   ( lcsh )
Cylindrocladium -- Control -- Florida   ( lcsh )
Spathiphyllum -- Diseases and pests -- 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: UF00065906
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 70666404

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i Some New Compounds for Control of Cylindrocladium Root
and Petiole Rot of Spathiphyllum
C Gntral Science
A. R. Chase Library
University of Florida, IFAS
Agricultural Research and Education Center ApopkTa 14 1987
AREC-Apopka Research Report, RH-86-9

S tI of Florida
One of the most serious diseases afflicting foliage-prlartss---
Cylindrocladium root and petiole rot of Spathiphyllum species and
cultivars. Many factors have been investigated for control of this disease
including potting medium type, soil temperature, cultivar resistance, and
chemical controls. To date, the most promising area of research has been
chemical control. During the first four years of this project, many older
established chemicals were evaluated for control of this disease, with the
result that only benomyl gave a sufficient level of control in most
instances. Under conditions of high disease pressure, even weekly
applications of benomyl drenches may fail to provide control of
Cylindrocladium root and petiole rot.

In 1984, several new fungicides were made available for testing at the
AREC-Apopka. Each was tested against Cylindro.cladium and several have
proven quite effective in controlling this disease on a wide number of
Spathiphyllum cultivars. The following report summarizes these tests.

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 a
maximum of 1500 ft-c natural light and temperatures ranging from 60 to
95F. Each test included noninoculated and inoculated control treatments.
Treatments were applied weekly for a total of 7 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 evaluated weekly
starting when the inoculated controls began to show symptoms. The rating
consisted of a visual grading scale evaluating the percentage of the plant
foliage showing symptoms of Cylindrocladium root and petiole rot. The
first three tests used 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.

1984 to 1986 trials comparing efficacy of various rates of new compounds

Tests were performed with dithianon (MF-711), triflumizole, and
prochloraz. All compounds were tested at the rate of 16 oz/100 gallons.
In the first test, prochloraz provided a high degree of control comparable
to that achieved with benomyl (Table 1). In the second test, prochloraz


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









and triflumizole both provided better disease control than did benomyl.
Dithianon failed to provide good disease control in either trial.

Four rates of benomyl or prochloraz were compared next. In this case,
the compounds provided a similar level of control when used at the same
rate with the exception of the 16 oz/100 gallon rate (Table 2). By the end
of the test, benomyl was slightly more effective than prochloraz. However,
rates of benomyl above 16 oz/100 gallons caused severe phytotoxicity on
treated plants.

Single and combination treatments of benomyl, prochloraz, and
triflumizole were compared in the next test. After 6 weekly applications,
only the benomyl treatment failed to provide adequate control of
Cylindrocladium root rot (Table 3).

Since benomyl was found phytotoxic at rates above 16 oz/100 gallons, a
trial was performed to evaluate potential phytotoxicity of triflumizole and
prochloraz at very high rates. In this case, no phytotoxicity occurred
even when plants were treated with up to 64 oz/100 gallons on a weekly
basis for 8 weeks (Table 4). In addition, all treatments gave good control
of Cylindrocladium root rot with the lowest rate of triflumizole slightly
less effective than other fungicide treatments.

Several tests were also run to evaluate a new compound which became
available late in 1985, PP 969. In these tests, PP 969, triflumizole, and
prochloraz were all compared at 1.5 and 3 oz/100 gallons. Although all
compounds provided some control, the PP 969 was most effective at these
very low rates (Table 5).

The final test comparing compounds for efficacy was performed in 1986
when SN 596 became available. In this trial, various rates and
combinations of SN 596 and prochloraz were compared to 16 oz/100 gallons of
benomyl. SN 596 was found ineffective in controlling Cylindrocladium while
prochloraz was effective even when used at 8 oz/100 gallons every other
week (Table 6).

1986 trials comparing timing and application intervals of triflumizole

Two tests were performed to determine the length of time between
applications of triflumizole which could provide control of Cylindrocladium
root rot. The first test utilized either 2 or 4 oz/100 gallons of
triflumizole applied 1, 2, or 4 times every 4 weeks. Although all
triflumizole treatments provided better control than benomyl used weekly,
only the higher rate applied 2 or 4 times or the lower rate applied weekly
gave adequate control in this test (Table 7). In the second test, rates of
either 8 or 16 oz/100 gallons were tested at the same intervals. In this
test, all application rates and intervals of triflumizole provided
excellent control of Cylindrocladium root rot (Table 8). Benomyl applied
weekly provided some control, but was less effective than triflumizole even
when triflumizole was applied at half the benomyl rate and only once every
four weeks.








The final test was performed to determine whether or not triflumizole
could act as a curative. In this case, plants were treated with either 2
or 4 oz of triflumizole/100 gallons before or after inoculation with the
pathogen at various times. Benomyl was applied at 8 oz/100 gallons at
similar times. Although benomyl provided slight disease control when
applied before or within 5 days of inoculation, it did not provide any
control when applied 18 days after inoculation (Table 9). Symptoms of
Cylindrocladium root rot did not appear within this 18 day period and
treatment of symptomatic Spathiphyllum would appear to be very ineffective.
In contrast, applications with triflumizole prior to inoculation provided
excellent disease control (Table 9). Since a significant degree of damage
occurred on plants treated with either rate of triflumizole after
inoculation, it seems apparent that the compound is not a curative.

Conclusions

1. The best new compounds for Cylindrocladium control on Spathiphyllum are
triflumizole and prochloraz.

2. These compounds are effective to a very similar level and can be used
at rates below that which is effective for benomyl.

3. Prochloraz is effective when used at 16 oz or more every 3 weeks or
less.

4. Triflumizole is effective when used at 8 to 16 oz every 2 to 4 weeks,
depending upon disease pressure.

5. Triflumizole, prochloraz and benomyl are not curatives.

6. Benomyl is labeled for use on foliage plants as Benlate 50WP.
Triflumizole has been proposed as a section 18 for this use and should
be available at the end of 1986 if clearance is granted. Efficacy of
prochloraz on several other diseases is currently being tested with
date of availablility on foliage plants uncertain.








0


Table 1. Efficacy of some fungicides for control of Cylindrocladium
root and petiole rot of Spathiphyllum.

Mean disease
severity rating
Rate oz/
Treatment 100 gal Test 1 Test 2

Noninoculated -- 1.0 ac 1.0 a
Inoculated -- 4. c 5.0 c
Triflumizole 16 NT 1.0 a
MF-711 16 2.8 b 2.6 b
Prochloraz 16 1.0 a 1.0 a
Benomyl 16 1.0 a 3.7 bc


plants were drenched at the rate of 1
10-5-84 (Test 1) or 10-26-84 (Test 2)
10 weeks.


pt/ft2 starting on
weekly for a total of


bMean disease severity for 10 replicates rated as follows: 1
no disease, 2 = 1-25% diseased, 3 = 26-50% diseased, 4 =
51-75% diseased, and 5 = 76-100% diseased, usually dead.
CNumbers in the same column followed by the same letter were
not significantly different using Duncan's new multiple
range test (5% level).
NT = Not tested.








Table 2. Effect of use of benomyl or prochloraz on efficacy
and phytotoxicity for Cylindrocladium root and petiole rot
of Spathiphyllum.

Rate oz/ Mean disease % plants with
Treatment 100 gal severity rating marginal necrosis


Noninoculated -- 1.2 ac 0 -
Inoculated -- 3.2 d 0
Benomyl 8 1.8 bc 0
Benomyl 16 1.2 a 10
Benomyl 24 1.1 a 80
Benomyl 32 1.3 ab 70
Prochloraz 8 1.9 c 0
Prochloraz 16 1.8 bc 0
Prochloraz 24 1.3 ab 0
Prochloraz 32 1.3 ab 0


plants were drenched at the rate
2-7-85 for a total of 8 weeks.


of 1 pt/ft2 weekly starting on


bMean disease severity rating for 10 replicates rated as follows:
1 = no disease, 2 = 1-25% diseased, 3 = 26-50% diseased, 4 =
51-75% diseased, and 5 = 76-100% diseased, usually dead.
CNumbers in the same column followed by the same letter were not
significantly different using Duncan's new multiple range test,
(5% level).








Table 3. Efficacy of benomyl, prochloraz, and triflumizole used
singly and in combination for control of Cylindrocladium root
and petiole rot of Spathiphyllum.


Rate oz/ Mean disease severity rating
Treatment 100 gal 5-16-85


Noninoculated -- 1.2 ac
Inoculated -- 4.0 c
Triflumizole 4 1.9 b
Triflumizole 8 2.1 b
Triflumizole and 4+
Benomyl 4 1.6 ab
Triflumizole and 4
Prochloraz 4+ 1.9 b
Prochloraz 4 1.6 ab
Prochloraz 8 1.5 ab
Prochloraz and 4+
Benomyl 4 1.2 a
Benomyl 8 3.8 c


plants were drenched at
4-1-85 for a total of 6


the rate of 1 pt/ft2
applications.


weekly starting on


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.
CNumbers in the same column followed by the same letter were not
significantly different using Duncan's new multiple range (5%
level).








Table 4. Effect of high rates of triflumizole and prochloraz
on phytotoxicity and efficacy for Cylindrocladium root
and petiole rot of Spathiphyllum.

Rate Mean percentage
Treatment oz/100 gal infection


Noninoculated --- 0 ac
Inoculated --- 35.4 c
Triflumizole 8.0 9.3 b
Triflumizole 16.0 0.5 a
Triflumizole 32.0 2.9 ab
Triflumizole 64.0 0.2 a
Prochloraz 8.0 0.8 a
Prochloraz 16.0 0.1 a
Prochloraz 32.0 0.1 a
Prochloraz. 64.0 0.1 a


aTreatments were applied weekly for a
soil drench (1 pt/ft surface area).


total of 8 weeks as a


percentage infection was rated for 10 plants approximately
9 weeks after treatments were initiated.
cMeans in the same column followed by the same letter were
not statistically different using Duncan's new multiple
range test (5% level).








Table 5. Effect of low rates of triflumizole, prochloraz,
and PP 969 on severity of Cylindrocladium root and
petiole rot of Spathiphyllum.
b Rate
Treatmentb oz/100 gal Percentage plant infection


Noninoculated --- 0 ac
Inoculated --- 96.2 e
Triflumizole 1.5 22.3 d
Triflumizole 3.0 12.1 d
Prochloraz 1.5 12.6 d
Prochloraz 3.0 10.1 cd
PP 969 1.5 4.7 bc
PP 969 3.0 1.8 ab


percentage infection was
9 weeks after treatments


rated for 10 plants approximately
were initiated.


bTreatments were applied weekly for a total of 8 weeks as a
soil drench (1 pt/ft surface area).
CMeans in the same column followed by the same letter were
not statistically different using Duncan's new multiple
range test (5% level).








Table 6. Effect of treatment interval and rate on efficacy of
benomyl, prochloraz, and SN 596 for Cylindrocladium root and
petiole rot of Spathiphyllum.

Number of
Rate applications Mean percentage
Treatment oz/100 gal per 4 weeks infection


Noninoculated -4 0 ac
Inoculated --- 4 21.1 a
Benomyl 16.0 4 7.4 bc
Prochloraz 8.0 4 1.6 ab
Prochloraz 16.0 4 0.3 ab
Prochloraz 26.7 4 0.5 ab
Prochloraz 16.0 2 3.2 ab
ProchToraz 26.7 2 0.2 ab
SN 596 0.2 1.3 44.4 d
Prochloraz and 26.7+
SN 596 0.2 1.3 0.8 ab


aTreatments were applied for a
soil drench (1 pt/ft surface


total of 8 weeks as a
area).


Percentage infection was rated for 10 plants approximately
9 weeks after treatments were initiated.
CMeans in the same column followed by the same letter were
not statistically different using Duncan's new multiple
range test (5% level).








Table 7. Effect of treatment interval and rates on efficacy
of benomyl and triflumizole for Cylindrocladium root and
petiole rot of Spathiphyllum.

Number of
Rate applications Mean percentage
Treatment oz/100 gal per 4 weeks infection


Noninoculated --- 4 0 ac
Inoculated --- 4 100.0 d
Triflumizole 4.0 4 17.7 b
Triflumizole 4.0 2 24.4 b
Triflumizole 4.0 1 62.6 c
Triflumizole 2.0 4 21.5 b
Triflumizole 2.0 2 56.0 c
Triflumizole 2.0 1 78.0 c
Benomyl 8.0 4 96.9 d

aTreatments were applied for a total of 8 weeks as a
soil drench (1 pt/ft surface area).
percentage infection was rated for 10 plants approximately
9 weeks after treatments were initiated.
CMeans in the same column followed by the same letter were
not statistically different using Duncan's new multiple
range test (5% level).








Table 8. Effect of treatment interval and rate on efficacy
of benomyl and triflumizole for Cylindrocladium root and
petiole rot of Spathiphyllum.

Number of
Rate applications Mean percentage
Treatment oz/100 gal per 4 weeks infection


Noninoculated --- 4 0 ac
Inoculated --- 4 98.7 d
Triflumizole 8.0 4 2.9 ab
Triflumizole 8.0 2 1.7 ab
Triflumizole 8.0 1 4.9 ab
Triflumizole 16.0 4 7.5 b
Triflumizole 16.0 2 2.9 ab
Triflumizole 16.0 1 4.0 ab
Benomyl 16.0 4 28.8 c


aTreatments were applied for a total
drench (1 pint/ft surface area).


of 8 weeks as a soil


percentage infection was rated for 10 plants approximately
9 weeks after treatments were initiated.
CMeans in the same column followed by the same letter were
not statistically different using Duncan's new multiple
range Test (5% level).








Table 9. Effect of treatment timing on efficacy of benomyl
and triflumizole on Cylindrocladium root and petiole rot
of Spathiphyllum.

a Rate Date of first Mean percentage
Treatment oz/100 gal treatment infection


Noninoculated --- 10 days before 0 ac
Inoculated --- 10 days before 87.9 f
Benomyl 8.0 10 days before 36.9 cd
Benomyl 8.0 5 days after 43.9 cd
Benomyl 8.0 18 days after 91.0 f
Triflumizole 4.0 10 days before 3.9 ab
Triflumizole 4.0 5 days after 13.8 bc
Triflumizole 4.0 18 days after 53.8 de
Triflumizole 2.0 10 days before 12.0 b
Triflumizole 2.0 5 days after 19.4 bc
Triflumizole 2.0 18 days after 67.3 ef


aTreatments were applied weekly for a
soil drench (1 pt/ft surface area).


total of 8 weeks as a


Percentage infection was rated for 10 plants approximately
9 weeks after treatments were initiated.

CMeans in the same column followed by the same letter were
not statistically different using Duncan's new multiple
range test (5% level).




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