| Material Information
||Influence of fertilization on severity of Erwinia blight and growth of Dieffenbachia
||ARC-A research report
||4 p. : ; 28 cm.
||Chase, A. R ( Ann Renee )
Poole, R. T ( Richard Turk )
Agricultural Research Center (Apopka, Fla.)
||University of Florida, IFAS, Agricultural Research Center-Apopka
||Place of Publication:
||Dieffenbachia -- Diseases and pests -- Florida ( lcsh )
Dieffenbachia -- Fertilizers -- Florida ( lcsh )
Erwinia -- Control -- Florida ( lcsh )
||government publication (state, provincial, terriorial, dependent) ( marcgt )
bibliography ( marcgt )
non-fiction ( marcgt )
||Includes bibliographical references (p. 4).
||Statement of Responsibility:
||A.R. Chase and R.T. Poole.
||Florida Historical Agriculture and Rural Life
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not reflect current scientific knowledge
or recommendations. These texts
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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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site maintained by the Florida
Cooperative Extension Service.
Copyright 2005, Board of Trustees, University
INFLUENCE OF FERTILIZATION ON SEVERITY OF ERWINIA
BLIGHT AND GROWTH OF DIFFENBACHIA HI ji L A
A. R. Chase and R. T. Poole
IFAS, University of Florida '
Agricultural Research Center -Apopka
ARC-A Research Report RH-82-6 .F S. o
One of the most serious diseases of dieffenbachias in Florida is Erwinia
blight caused by the bacteria Erwinia chrysanthemi and E. carotovora. Erwinia
blight was first described in 1960 in California (6) and in 1961 in Florida (5),
and is characterized by dark, water soaked leaf spots and mushy, slimy stem
lesions at the soil line. Lower leaves also wilt and turn chlorotic under severe
infections. The bacteria inhabit the interior of the stem and since none of the
chemicals presently available for bacterial disease control are highly systemic,
the disease is very difficult to control. Alternative means of decreasing
disease losses are therefore important. The ability of a host plant to resist
disease can be influenced by the nutritional status of that host. The following
study was conducted to determine the relationship of Erwinia blight and nutrition
The first experiment was conducted between October 1980 and April 1981 on
D. maculata 'Perfection' and 'Rudolph Roehrs' obtained from pathogen-free tissue
cultured plants. Ten cuttings of each cultivar were rooted and grown in steam
sterilized potting medium without fertilizer for 4 weeks. N, P, and K was
obtained from NH4NO3, KNO3, and H3PO4 with a N:P:K ratio of 2:1:2. Dolomite and
Micro Max were incorporated at 7 and 1l pounds per yard prior to potting into
6 inch pots. The recommended rate is 1,200 pounds/acre/year of nitrogen (1).
Fertilizer treatments initiated on November 24, 1980 consisted of the following
rates applied as a liquid on a weekly basis: 1000, 2000, 3000, 4000, 5000, and
6000 Ibs N/acre/year. On April 2, 1981 plant height was recorded and leaves
were inoculated with Erwinia chrysanthemi by injecting a suspension of the
bacterium into them in 15 locations/plant. After 2 weeks the number of
lesions (leaf spots) and their sizes per plant were recorded (Tables 1 and 2).
The middle fertilizer rates produced the tallest plants and lowest disease
The second experiment was performed between May 1981 and September 1981,
using D. maculata 'Perfection' plants. Fifteen plants established as described
earlier were used for each of the following treatments: 1) 1000, 2) 2000,
3) 3000, 4) 4000, 5) 5000, 6) 6000, 7) 7000, and 8) 8000 Ibs N/acre/year applied
as 14:14:14 Osmocote, 4 grams per 6 inch pot is equivalent to 1000 bs N/acre/year
when applied 4 times annually. The remainder of this experiment was performed
as described earlier. Plant height and disease severity were both affected by
fertilizer treatments (Table 3). The same trend in optimum plant growth and
minimum disease for the intermediate treatments was seen in this experiment.
Treatments 3 and 4 gave best plant growth combined with lowest disease severity.
Little research has been conducted to investigate the role of host plant
nutrition on disease severity in foliage plants. High levels of nitrogen
resulted in low levels of Phytophthora leafspot of philodendron while lower
levels supported the best plant growth (3). Similar results were found for
Xanthomonas disease of the same plant with high nitrogen decreasing disease
severity (2). Results from Erwinia studies with Philodendron selloum indicated
that high levels of nitrogen again decreased the disease severity (4), while also
reducing plant growth. Our studies indicate that excessive fertilizer can have
a different effect on disease severity. Plants produced under middle nutrition
levels (3000-4000 Ibs N/acre/yr, 1200 Ibs recommended rate) (1) would be more
resistant to Erwinia leafspot than those produced under stress conditions
resulting from either insufficient or excessive fertilizer regimes. Since our
conclusions differ from those of research from the past on other plants, it
seems likely that the influence of nutrition on disease resistance cannot be
stated as a single rule for all diseases and plants. The influence of nutrition
on disease should be investigated in each situation to determine optimum levels
for plant growth and disease reduction,especially in situations where disease is
poorly controlled with chemicals.
Table 1. Effect of fertilization on height and Erwinia
leaf spot severity of Dieffenbachia maculata 'Perfection'
Treatment Plant ht Mean No.
Ibs NPK/acre/yr (cm) leaf spots/plant
1000 56.3 5.0
2000 56.7 2.4
3000 56.7 1.6
4000 54.3 1.6
5000 51.6 1.0
6000 49.1 3.6
Table 2. Effect of fertilization on height and Erwinia
leaf spot severity of Dieffenbachia maculata 'Rudolph
Roehrs' (Expt. 1).
Treatment Plant ht Mean No.
Ibs NPK/acre/yr (cm) leaf.spots/plant
1000 57.3 2.0
2000 65.2 3.0
3000 68.4 1.6
4000 63.6 1.6
5000 63.7 2.0
6000 58.7 3.4
Table 3. Effect of Osmocote fertilization on height and
Erwinia leaf spot severity of Dieffenbachia maculata
'Perfection' (Expt. 2).
Treatment Plant ht Mean leaf spot
Ibs NPK/acre/yr (cm) size (mm)
1000 40.9 9.25
2000 44.6 8.10
3000 44.3 6.45
4000 45.2 6.20
5000 44.6 6.88
6000 41.2 7.52
7000 42.3 7.32
8000 41.1 7.85
1. Conover, C. A. and R. T. Poole. 1981. Guide for fertilizing tropical
foliage plant crops. ARC-A Research Report RH-81-1.
2. Harkness,R. W. and R. B. Marlatt. 1970. Effect of nitrogen, phosphorus
and potassium on growth and Xanthomonas disease of Philodendron oxycardium.
J. Amer. Soc. Hort. Sci. 95(1):37-41.
3. Harkness, R. W. and J. E. Reynolds. 1964. Effect of nitrogen and
potassium nutrition on the phytophthora leaf spot of Philodendron
oxycardium. Proc. Fla. State Hort. Soc. 77:475-480.
4. Haygood, R. A. and D. L. Strider. 1982. Influence of nitrogen and
potassium on growth'and bacterial leaf blight of Philodendron selloum.
Plant Disease 66: (In press).
5. McFadden, L. A. 1961. Bacterial stem and leaf rot of dieffenbachia in
Florida. Phytopathology 51:663-668.
6. Munnecke, D. E. 1960. Bacterial stem rot of dieffenbachia. Phytopathology