Group Title: CFREC-Apopka research report - Central Florida Research and Education Center-Apopka ; RH-90-3
Title: Effect of nitrogen and potassium on growth of Ficus benjamina and severity of Xanthomonas leaf spot
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00065871/00001
 Material Information
Title: Effect of nitrogen and potassium on growth of Ficus benjamina and severity of Xanthomonas leaf spot
Series Title: CFREC-Apopka research report
Physical Description: 5 p. : ill. ; 28 cm.
Language: English
Creator: Chase, A. R ( Ann Renee )
Central Florida Research and Education Center--Apopka
Publisher: IFAS, University of Florida, Central Florida Research and Education Center-Apopka
Place of Publication: Apopka FL
Publication Date: 1990
 Subjects
Subject: Ficus (Plants) -- Growth -- Florida   ( lcsh )
Ficus (Plants) -- Diseases and pests -- Control -- Florida   ( lcsh )
Plants -- Effect of nitrogen on -- Florida   ( lcsh )
Plants -- Effect of potassium on -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references (p. 2).
Statement of Responsibility: A.R. Chase.
General Note: Caption title.
 Record Information
Bibliographic ID: UF00065871
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 70551139

Full Text





HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
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
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida





]0o



fQL Effect of nitrogen and potassium on growth of Ficus benjamin
W a and severity of Xanthomonas leaf spot
'- A. R. Chase' Library
IFAS, University of Florida
Central Florida Research and Education Center /- Apopkar'? 21 9
CFREC-Apopka Research Report, RH-90-3
/ cf. or'v-^
A major project studying the role of fertilizer in bacterial disease -
severity has been conducted at the Central Florida Research and Education
Center in Apopka over the past ten years. Many diseases of foliage plants,
caused by Xanthomonas campestris pathovars, are less severe when plants
receive higher than recommended rates of a balanced fertilizer whether in a
slow-release or liquid form. Additional research on some plants showed that
nitrogen was the most important nutrient, although potassium and phosphorus
also can affect disease severity. The following research was conducted to
determine effects of nitrogen and potassium on severity of Xanthomonas leaf
spot of Ficus benjamin caused by X. campestris pv. fici.

Ficus benjamin cuttings were established in steam-treated potting medium
consisting of Canadian peat and pine bark (1:1 by volume). The medium was
amended with 7 Ibs dolomitic lime and 1 lb of Micromax per cubic yard. Single
superphosphate was added as a top dressing, prior to testing, at about 1 g/6
inch pot. Three experiments were performed between May and December 1989. In
each experiment, ten plants in 6 inch pots were used per treatment.
* Treatments included three rates of a slow-release nitrogen (39:0:0 3, 6, or
9 g/pot) in combination with three rates of potassium (0:0:46 2.5, 5.0, and
7.5 g/pot). Plants were irrigated by hand two or three times a week as
needed. Maximum light levels were 3000, 2500, and 2200 ft-c for experiments
1, 2, and 3, respectively. Minimum and maximum temperatures were about 60 to
950F depending upon time of year. Leachate for electrical conductivity and pH
measurements was obtained monthly by adding water to the surface of each pot
until about 4 oz of leachate collected in a beaker beneath the pot. Plants
were grown for two months following the fertilizer application. Plant height
was recorded at test initiation and completion. In experiments 2 and 3, top
quality was rated also on the following scale: 1 dead; 2 poor, unsalable;
3 = moderate, salable; 4 good, salable; and 5 excellent, salable.

One day prior to inoculation, intermittent misting was initiated and
continued until test completion. Plants were inoculated with a suspension of
Xanthomonas campestris pv. fici adjusted to 1 x 10 bacteria/ml. The
suspension was sprayed onto leaves and plants were covered with a plastic bag
for one day. The number of lesions per plant was recorded 7 to 14 days after
inoculation.

Leachate electrical conductivity increased as nitrogen level increased,
but was not consistently affected by increases in potassium level (Table 1).
Leachate pH was affected by nitrogen level but results were inconsistent
(Table 1). Increasing nitrogen level decreased plant height in the first
experiment but had no effect on height in experiments 2 and 3 (Figure 1).

* IProfessor of Plant Pathology, Central Florida Research and Education Center,
2807 Binion Rd., Apopka, FL 32703.









Top quality slightly increased as potassium level increased in experiment 2
and increased as nitrogen level increased in experiment 3 (Figure 2).

The number of lesions per plant decreased as nitrogen level increased in
each of the three experiments (Figure 3). Potassium level affected disease
severity in experiment 1 only with increased potassium levels decreasing
number of lesions. Disease severity was reduced significantly when nitrogen
level was increased. Intermediate rates of nitrogen should reduce disease
severity significantly without damaging the host. Although the highest rate
of nitrogen did not appear to reduce top quality very much in these
experiments, lower rates should be employed to minimize fertilizer cost,
potential for ground water contamination and damage to the crop under other
growing conditions. Additional information on the role of fertilizer in
severity of Xanthomonas leaf spot of Ficus can be found in the paper listed
below.

Reference

1. Chase, A. R. 1988. Effect of fertilizer rate on susceptibility of Ficus
benjamin to Xanthomonas campestris pv. fici. Proc. Fl. State Hort. Soc.
101:339-340.


-2-









Table 1. The effect of nitrogen and potassium levels on
conductivity and pH of leachate for Ficus benjamin.


electrical


Leachate
Nitrogen Potassium electrical conductivity
g 39:0:0 g 0:0:46 pnmhos/cm Leachate pH
per 6 inch pot per 6 inch pot Test 1 Test 2 Test 3 Test 1 Test 2 Test 3

3 2.5 680 460 1080 6.2 5.0 6.3
3 5.0 910 1100 1720 6.4 6.0 6.6
3 7.5 1620 1140 2160 6.5 5.9 6.6
6 2.5 1870 1570 5110 6.0 6.1 4.5
6 5.0 2700 1430 7020 6.0 5.7 4.5
6 7.5 2720 4830 8870 6.0 5.7 4.6
9 2.5 2920 4200 5990 5.5 5.2 4.0
9 5.0 2390 1780 6890 6.0 4.9 4.3
9 7.5 3240 3550 8420 6.0 5.2 4.3

Significance"
Nitrogen rate (N) ** ** ** ns **
Potassium rate (K) ns ns ** ** ns ns
N x K interaction ns ns ns ns ns ns

"Significant effects were evaluated using analysis of variance and denoted as
significant at the 5% (*) or 1% (**) level or not significant (ns).


-3-







Figure 1. The effect of nitrogen and potassium levels on
height of Ficus benjamin 2 months after fertilizer
application.


0


N-3 N-3
K-2.5 K-S


N-3 N-6 N-6
K-7.5 K-2.5 K-5


N-6 N-9
K-7.5 K-2.5


FERTILIZER TREATMENT

Figure 2. The effect of nitrogen and potassium levels on top
quality of Ficus benjamin 2 months after fertilizer application.
Top quality was rated on the following scale: 1 = dead; 2 = poor,
unsalable; 3 = moderate, salable; 4 = good, salable, and 5 =
excellent, salable.


N-3 N-3 N-3 N-6 N-6 N-6 N-9 N-9 N-9
K-2.5 K-5 K-7.5 K-2.5 K-5 K-7.5 K-2.5 K-5 K-7.5
FERTILIZER TREATMENT


-4-


N-9
K-7.5









Figure 3. The effect of nitrogen and potassium levels on
number of lesions on Ficus benjamin caused by
Xanthomonas campestris pv. fici.


N-3 N-3 N-3 N-6 N-6 N-6 N-9 N-9 N-9
K-2.5 K-5 K-7.5 K-2.5 K-5 K-7.5 K-2.5 K-5 K-7.5

FERTILIZER TREATMENT


-5-







University of Florida Home Page
© 2004 - 2010 University of Florida George A. Smathers Libraries.
All rights reserved.

Acceptable Use, Copyright, and Disclaimer Statement
Last updated October 10, 2010 - - mvs