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SUNI ITY OF Central Florida Research
SFLORIDA and Education Center
Institute of Food and Agricultural Sciences Research Report
Are Your Syngoniums Resistant to Disease? ib
SEP 3 0 1994
A. R. Chase1,2
CFREC-Apopka Research Report RH-93-19 University of Florida
One of the most devastating diseases of foliage plants is caused by the bacterial pathogen,
Xanthomonas campestris pv. dieffenbachiae. This disease was first found in 1986 causing severe
necrosis of the foliage primarily on 'White Butterfly' which has been the most widely grown
cultivar for the past decade. At the time, many of the currently produced syngoniums were
tested and found susceptible. No attempts were made to determine levels of resistance since
none of the cultivars appeared sufficiently resistant to the pathogen. In addition, bactericides
have proven ineffective in controlling the disease partially due to its systemic nature.
One method of combating this serious disease was breeding and selection of new
syngoniums for resistance to Xanthomonas blight. In the early 1990's, a commercial grower
selected 17 lines of Syngonium podophyllum (and other species of syngonium) for resistance to
Xanthomonas campestris pv. dieffenbachiae as well as other desirable characteristics. These
lines were tested at the CFREC-Apopka initially in December 1990 with two standing out as
significantly more resistant to Xanthomonas than 'White Butterfly'. These two selections were
propagated and three additional tests compared them to commercially available 'White Butterfly'
in January 1991, November 1992 and May 1993. In each test, the two "resistant" lines showed
significantly lower disease levels than 'White Butterfly' (Figure 1).
Another project was started in the late spring of 1993 to evaluate 36 lines of
commercially available syngoniums for resistance to Xanthomonas. 'White Butterfly', 'Robusta'
and 'Pixie' were represented by more than one source and were denoted as I, II or III. Plants
were tested in August 1993. During this first test, plants became naturally infected with
Myrothecium roridum, the cause of Myrothecium leaf and petiole rot, another troublesome
disease on Syngonium. Both Xanthomonas blight and Myrothecium leaf spot were rated in this
'Professor of Plant Pathology, University of Florida, IFAS, Central Florida Research and
Education Center, 2807 Binion Rd., Apopka, FL 32703.
2Special thanks to R. W. Henley for use of his syngonium stock plants and to Jeanne Yuen for
her invaluable assistance in interpreting these tests.
The Institute of Food and Agricultural Sciences is an Equal Employment Opportunity Affirmative Action Employer authorized to provide research, educational
information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap or national origin.
COOPERATIVE EXTENSION WORK IN AGRICULTURE, HOME ECONOMICS, STATE OF FLORIDA, IFAS, UNIVERSITY OF FLORIDA,
U.S. DEPARTMENT OF AGRICULTURE, AND BOARDS OF COUNTY COMMISSIONERS COOPERATING.
and again plants became naturally infected with M. roridum and developed Myrothecium leaf
spot. Table 1 lists the cultivars by their level of resistance to Xanthomonas and Myrothecium.
Many of the cultivars showed different resistance levels to one or both of the pathogens
when compared to the other cultivars. 'Pride' showed low resistance to both Xanthomonas and
Myrothecium while 'Emerald Green' (originally from seeds) had very high resistance to both
pathogens (Table 1). Other cultivars showed intermediate and sometimes different levels of
resistance to the two pathogens.
Observations regarding the tendency of each selection to vine and their overall visual
grade which reflected salability and consistency of the final product were also made. Nearly all
of the Allusion cultivars had good to excellent visual grades and slight vining if any (Table 2).
The three 'White Butterfly' selections had the highest degree of vining in addition to 'Maya Red'
and 'Freckles'. Only 'Picasso' performed poorly in overall visual grade in these tests. This
information should assit in development of superior plants by allowing breeders to choose
cultivars with more desirable characteristics for breeding stock.
Relative resistance of Syngonium cultivars to Xanthomonas campestris pv.
dieffenbachiae and Myrothecium roridum.
Degree of Cultivar resistance to Xanthomonas Cultivar resistance to Myrothecium
Very low Bold Allusion Pixie II, Robust Allusion
Low Bold, Cream Allusion, Cream Tetra, Gold Allusion, Lemon Lime, Silver
Gold Allusion, Pride Robusta
Some Bob Allusion, Flutterby, Gold, Bold Allusion, Cream Allusion,
Lemon Lime, Matisse, Pink Cream Tetra, Degas, Flutterby,
Allusion, Pixie I, Robust Allusion, Freckles, Maya Red, Renior,
Silver Robusta, Wenlandii Robusta II, Roxanne, Wenlandii,
White Butterfly I
Good DaVinci, Goya, Monet, Renoir, Gold Allusion, Monet, Patricia,
Robusta I, White Butterfly I and II Pink Allusion, Pixie I, Pride,
High Freckles, Holly, Patricia, Robusta Bob Allusion, Bold, Dali, Holly,
II, White Butterfly III White Butterfly II and III
Very high Dali, Degas, Maya Red, Picasso,
Nearly Emerald Green (seeds), Roxanne Emerald Green (seeds), DaVinci,
immune Gold, Goya, Matisse, Picasso
Relative rating of Syngonium cultivars according to vining and overall visual
Degree of Cultivar Visual Cultivar
None Bold, Bold Allusion, Excellent Bob Allusion, Bold, Cream
Flutterby, Gold Allusion, Allusion, Flutterby, Gold
Holly, Lemon Lime, Allusion, Goya, Holly,
Patricia, Pixie I, Pride, Lemon Lime, Matisse, Pink
Robust Allusion, Robusta I, Allusion, Pixie I and II,
Robusta II Pride, Robust Allusion,
Slight Bob Allusion, Cream Good Bold Allusion, Freckles,
Allusion, Dali, DaVinci, Gold, Maya Red, Monet,
Degas, Emerald Green (from Patricia, Renoir, Silver
seeds), Gold, Matisse, Robusta, White Butterfly I,
Monet, Picasso, Pixie II, II, and III
Silver Robusta, Wilsonii,
Moderate Cream Tetra, Goya, Pink Moderate Cream Tetra, Dali, Degas,
Allusion, Renoir, Roxanne, Emerald Green (from seeds),
Wenlandii Matisse, Maya Red,
High Freckles, Maya Red, White Poor Picasso
Butterfly I, II and III
Figure 1. Severity of Xanthomonas leaf spot on two "resistant" lines of Syngonium
compared to 'White Butterfly'.
= Jan 90 E Dec 92 I May 93 = July 93