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Group Title: ARC-A research report - Agricultural Research and Education Center - RH-82-21
Title: Potting medium compaction and Pythium root rot of Peperomia and Pothos
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Permanent Link: http://ufdc.ufl.edu/UF00066505/00001
 Material Information
Title: Potting medium compaction and Pythium root rot of Peperomia and Pothos
Series Title: ARC-A research report
Physical Description: 7 p. : ; 28 cm.
Language: English
Creator: Chase, A. R ( Ann Renee )
Conover, Charles Albert, 1934-
Agricultural Research Center (Apopka, Fla.)
Publisher: University of Florida, IFAS, Agricultural Research Center-Apopka
Place of Publication: Apopka FL
Publication Date: 1982
 Subjects
Subject: Plants -- Effect of soil compaction on -- Florida   ( lcsh )
Roots (Botany) -- Diseases and pests -- Control -- Florida   ( lcsh )
Peperomia -- Diseases and pests -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references (p. 3).
Statement of Responsibility: A.R. Chase and C.A. Conover.
General Note: Caption title.
Funding: Florida Historical Agriculture and Rural Life
 Record Information
Bibliographic ID: UF00066505
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: oclc - 71231546

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HISTORIC NOTE


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Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
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Copyright 2005, Board of Trustees, University
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\POTTING MEDIUM COMPACTION AND PYTHIUM ROOT ROT OF PEPEROMIA AND POTHOS

0 A. R. Chase and C. A. Conover
IFAS, University of Florida ---.
Agricultural Research Center-Apopka
Research Report, RH-1982-21 !

Research concerning effects of soil compaction on severity of fungat J
root rot diseases has received considerable attention during -the past few
years (1,3). In these experiments, disease severity was reduced by '
increasing soil aeration and decreasing compaction, resulting in better
root growth. Soil compaction increases the water:air ratio which favors
development of some fungal root rot diseases. Conover and Poole (2)
reported that top growth of Pilea pubescens (Silver tree) was not reduced,
while root growth was restricted when media were compacted up to 0.3 kg/cm-,
but no disease involvement was observed. The effect of medium compaction
on Pythium root rot and growth of two foliage plants was tested and is
reported here.
Peperomia obtusifolia and Epipremnum aureum (pothos) were propagated
from pathogen-free cuttings and rooted in steam-sterilized potting medium
consisting of Canadian peat and pine bark (3:1 by volume) amended with
10 lb Osmocote (14:14:14), 7 1b- dolomite, and 1 b Micromax (micro-
3
nutrient source) per yd Cuttings were planted in 4" pots (two per pot
for pothos and one per pot for peperomia). Treatments included compaction
levels of 0, 2 and 4 psi on both inoculated and noninoculated plants
(total of 6 treatments replicated 10 times). A compaction level of 0 was
equivalent to gravity plus settling due to irrigation. Three experiments
were performed between 6-23-81 and 5-1-82. At the completion of each
experiment, quality (height, color and overall appearance) and disease
ratings were recorded.
In Experiment 1, an increase in compaction resulted in decreased plant
quality of peperomia but not pothos (Tables 1 and 2). Inoculation with
Pythium sp. reduced quality and height or vine length of both plants.
There was an interaction between compaction and Pythium sp. infection of
pothos (Table 2), resulting in poorest quality plants produced with Pythium
sp. infection and the lowest degree of compaction.
The influence of medium compaction and Pythium sp. infection in
Experiment 2 were not consistent with the results of Experiment 1. In this







experiment, increased compaction rates resulted in increased vine length
but did not significantly influence quality of foliage or roots of pothos
(Table 3). Increased compactions also resulted in increased heights of
peperomias but had no other significant effect on foliar or root quality
(Table 4). As in the first test, presence of Pythium sp. in the potting
medium reduced quality ratings of both plants. The only interaction
between the two factors occurred with peperomia height where the shortest
plants were produced with the least compaction and Pythium sp. present,
which was the same trend as the pothos in Experiment 1.
In Experiment 3, results differed again. Pothos were not significantly
influenced by any treatment. However, peperomia root and quality grades
were both reduced as medium compaction increased. In addition, Pythium sp.
infections caused lower quality ratings and plant stunting. An inter-
action between Pythium sp. and compaction produced poorest quality plants
when infected with Pythium sp. and grown at the highest compaction level,
which was the opposite of the earlier trends.
Results of these tests are variable with respect to the influence
of compaction on plant growth and quality, Pythium root rot consistently
reduced quality of both pothos and peperomia. Increasing compaction level
generally had negative effects on root development of both plants, and
negative to positive effects on foliage quality. Peperomia appeared to
be more sensitive to medium compaction than pothos in these tests. Although
interactions between Pythium root rot and compaction were not consistent,
they did occur. The variability in results from one experiment to the next
may be due to the variability in water applied to these plants due to time
of year. Experiment 3 plants required the highest water levels since
they were grown in the summer. It is possible that insufficient water was
supplied, resulting in variable effects. This would explain the lack of
root rot found on pothos since a certain level of soil moisture must be
present for disease development. In Experiments 1 and 2, the low
compaction levels resulted in the most severe root rot while in the third
experiment the high compaction rate resulted in the most severe root rot
ratings. A compaction degree of about 2 psi may be the most beneficial
for production of good plants and minimization of root rot damage and is
in agreement with results noted by Conover and Poole on pilea without the
presence of disease. The influence of compaction on top growth appears to


-2-








be less consistent than that on root growth and may be dependent upon
plant species.

References:
1. Burke, D. W., D. E. Miller, L. D. Holmes and A. W. Barker. 1972.
Counteracting bean root rot by loosening the soil. Phytopathology
62:306-309.
2. Conover, C. A. and R. T. Poole. 1981. Effect of soil compaction on
physical properties of potting media and growth of Pilea pubescens
Liebm. 'Silver tree'. HortScience 106:604-607,
3. Miller, D. E., and D. W. Burke. 1975. Effect of soil aeration on
Fusarium root rot of beans. Phytopathology 65:519-523.


Table 1. Effect of medium compaction and Pythium
quality of Peperomia obtusifolia (Experiment 1,


root rot on growth and
6-23-81 to 11-10-81).


Plant height (in) Plant quality a
Compaction level (psi) 9-24-81 11-10-81 9-24-81 11-10-81

0 4.0 7.3 3.1 3.9
2 4.3 7.4 3.0 3.5.
4 3.8 6.7 2.4 3.3

Inoculation

Pythium sp. 3.1 5.7 1.6 2.4

Control 5.0 8.6 4.2 4.8

Significant effects

Compaction (c) linear NSb .05 .05 .01
quadratic NS NS NS NS

Inoculation (I) linear .01 .01 .01 .01


aQuality rating was made
given.


on a scale from 1 (dead) to 5 (good) on the dates


b05 significant at the 5% level.
.01 significant at the 1% level.
NS not significant.






Table 2. Effect of medium compaction and Pythium root rot on growth and
quality of Epipremnum aureum (Pothos) (Experiment 1, 6-23-81 to 11-10-81).

Vine length (in) Plant quality
Compaction level (psi) 9-24-81 9-24-21 11-10-81

0 11.8 3.2 3.4
2 16.6 4.0 3.6
4 15.4 3.9 3.6

Inoculation

Pythium sp. 12.4 3.0 2.8

Control 16.8 4.5 4.3

Significant Effects

Compaction (C) linear .05b .01 NS
quadratic NS .01 NS

Inoculation (I) linear .01 .01 .01
(C x I) interaction NS .05 .01


quality rating was made
given:


on a scale from 1 (dead) to 5 (good) on the dates


b05 significant at the 5% level.
.05 significant at the 1% level.
.01 significant at the % level.
NS not significant.








Table 3. Effect of medium compaction and Pythium root rot on growth and
quality of Epipremnum aureum (Pothos) (Experiment 2, 11-30-81 to 2-18-82).

Quality
Compaction level (psi) Vine length (in) Foliage Roots

0 9.6 2.8 3.0
2 11.2 3.1 2.8
4 12.9 3.1 2.7

Inoculation

Pythium sp. 6.0 1.7 1.2

Control 16.4 4.3 4.6

Significant Effects

Compaction (C) linear .01b NS NS
quadratic NS NS

Inoculation (I) linear .01 .01 .01

aQuality rating was made on a scale from 1 (dead) to 5 (good).
b.05 significant at the 5% level.
.01 significant at the 1% level.
NS not significant.







Table 4.
quality


Effect of medium compaction and Pythium root rot on growth and
of Peperomia obtusifolia (Experiment 2, 11-30-81 to 2-18-82).


Qualitya
Compaction level (psi) Vine length (in) Foliage Roots

0 5.8 3.4 3.1
2 5.8 3.6 3.0
4 6.3 3.8 3.2

Inoculation

Pythium sp. 5.2 2.8 1
4.6
Control 6.9 4.4 4

Significant Effects
b
Compaction (C) linear .01 NS NS
quadratic .01 NS NS

Inoculation (I) linear .01 .01 ,01
C x .01 NS NS


aQuality rating was made on a scale of 1 (dead) to 5 (good).
.05 significant at the 5% level.
.01 significant at the 1% level.
NS not significant.


-6-







Table 5. Effect of medium compaction and Pythium root rot on growth and
quality of Peperomia obtusifolia (Experiment 3, 5-20-82 to 7-19-82).

Qualitya
Compaction level (psi) Plant height (in) Foliage Roots

0 6.5 3.8 3.8
2 5.9 3.4 2.7
4 5.6 3.6 2.9

Inoculation

Pythium sp. 4.9 2.7 1.7

Control 7.1 4.5 4.5

Significant Effects
Compaction (C) linear NSb .05 .01
quadratic NS

Inoculation (I) linear .01 .01 ,01
C x I NS .01 .. NS


aQuality rating was made on

b.05 significant at the 5%
.01 significant at the 1%
NS not significant.


a scale of 1 Cdead) to 5 (good),

level.
level.


-7-


!*




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