Using temperature information to aid in controlling diseases of ornamentals

Material Information

Using temperature information to aid in controlling diseases of ornamentals
Series Title:
CFREC-Apopka research report
Chase, A. R ( Ann Renee )
Conover, Charles Albert, 1934-
Central Florida Research and Education Center--Apopka
Place of Publication:
Apopka FL
University of Florida, Central Florida Research and Education Center-Apopka
Publication Date:
Physical Description:
5 p. : ; 28 cm.


Subjects / Keywords:
Plants, Ornamental -- Diseases and pests -- Control -- Florida ( lcsh )
Plants, Ornamental -- Effect of temperature on -- Florida ( lcsh )
Diseases ( jstor )
Xanthomonas campestris ( jstor )
Plants ( jstor )
government publication (state, provincial, terriorial, dependent) ( marcgt )
non-fiction ( marcgt )


General Note:
Caption title.
Statement of Responsibility:
A.R. Chase and C.A. Conover.

Record Information

Source Institution:
University of Florida
Holding Location:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
70109797 ( OCLC )


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/- A. R. Chase and C. A. Conover P 0 S99

University of Florida, IFAS Univers,
Central Florida Research and Education Center Alph O rida
CFREC-Apopka Research Report, RH-91-8

Most plant diseases exhibit a characteristic range of temperatures for optimal
development. Often this range is the same as that for optimal production of the host plant, but
in other cases, plants can be produced with a temperature range which is not favorable for a
particular plant pathogen. For example, Myrothecium leaf spot of foliage plants is most severe
when temperatures are in the range of 70 to 810F (Table 1). Since many foliage plants can be
produced at temperatures above 81"F, Myrothecium leaf spot can be avoided during times when
temperatures regularly exceed 81 F. In contrast, Rhizoctonia aerial blight can develop over a
relatively wide range of temperature from as low as 59 F, but cease development if the potting
medium temperature exceeds 90*F or the air temperature exceeds 95*F. Such conditions are
not unusual during summer months in Florida and Texas but would not be common in many
other foliage growing areas such as Hawaii and California. The relatively narrow range of
optimum temperatures for development of Botrytis blight (64 72*F) explains why this disease
is not as common in subtropical climates as in temperate climates even when susceptible plants
are produced.

Knowing the optimal temperatures for development of a given disease is best used for
timing control measures rather than altering the growing environment. This information is also
helpful to disease diagnosticians since they can make special effort to look for target pathogens
at certain times of the year. Hibiscus produced in Florida are subject to three bacterial leaf spot
diseases which have different temperature optima. During winter months, Pseudomonas
syringae pv. hibisci occurs with Pseudomonas cichorii common during the spring and fall. In
general, only Xanthomonas campestris pv. malvacearwn is active on this plant during summer
months. Although certain diseases tend to occur during the winter and others only during the
summer, growers should be prepared for exceptions. Production innovations such as under
bench heating have affected more than plant production and fuel costs during winter months.
Diseases such as Cylindrocladium root rot of Spathiphyllum spp. which usually do not develop
during the cooler winter months, now occur year round when plants are produced with under
bench heating.

Scouting for diseases only at times when temperatures are favorable allows for better
management of personnel resources. In addition, when preventive pesticides are recommended
they can be applied only when disease development is possible and not on a year round basis,
which is costly and potentially hazardous to plants and workers, and could also lead to

~ G ~~ f"

Tables 1 and 2 give the optimum air temperature ranges for some ornamental diseases.
This information was obtained from a variety of references as well as new research. Table 1
:an best be used if the disease in question has been correctly diagnosed. If the disease is not
cnown, Table 2 may be more useful since it is arranged by plant rather than by pathogen.
Although these tables represent the majority of the information available on temperature ranges
)f ornamental diseases they fall short of covering all ornamental diseases. If a specific disease
s not listed for the plant you are interested in checking, it is likely that the same disease will
ict similarly on another host. This can readily be seen by examining the information on
Rhizoctonia diseases which are all most severe with temperatures between about 70 and 90*F.
3e sure to obtain a reliable diagnosis whenever you encounter a new problem or one that seems
o occur at an unusual time of year or under suboptimal temperature conditions. Many diseases
producee similar symptoms and laboratory culturing is necessary for an accurate diagnosis.

Table 1. Optimal temperatures for some diseases of ornamentals arranged by pathogen.
Optimal air
Pathogen Plant (common name) range (*F)
Alternaria panax Brassaia actinophylla (schefflera) 59 75
Botrytis spp. various 64-72
Corynespora cassiicola Aeschynanthus pulcher (lipstick vine)

Table 1. Optimal temperatures for some diseases of ornamentals arranged by pathogen.

Optimal air
Pathogen Plant (common name) range (*F)
Pseudomonas cichorii Pelargonium x horrorum (geranium) 68 82
Pseudomonas solanacearum Pelargonium spp. 72 95
Pseudomonas syringae Impatiens Wallerana 70 86
Pseudomonas syringae pv. Hibiscus rosa-sinensis 59 64
Rhizoctonia solani Begonia (wax begonia) 70 91
Rhizoctonia solani Epipremnum aureum (pothos) 68 86
Rhizoctonia solani Impatiens Wallerana 68 95
Rhizoctonia solani Nephrolepis exaltata (Boston fern) air less than 95
soil less than 90
Xanthomonas campestris pv. Dieffenbachia maculata 86 91
Xanthomonas campestris pv. Syngonium podophyllum nephthytiss) 79 86
Xanthomonas campestris pv. Hedera helix (English ivy) 68 86
Xanthomonas campestris pv. Hibiscus rosa-sinensis 75 91
Xanthomonas campestris pv. Pelargonium spp. 77 86
Xanthomonas campestris pv. Strelitzia reginae (bird-of-paradise) 70 81
Xanthomonas campestris pv. Zinnia elegans 70 84


Table 2. Optimal temperatures for some diseases of ornamentals arranged by plant.
Optimal air
Plant Pathogen range ("F)
Aeschynanthus Corynespora cassiicola
Aphelandra Phytophthora parasitica 81 91
Begonia Rhizoctonia solani 70 91
Bougainvillea Pseudomonas andropogonis 75 91
Brassaia Alternaria panax 59 75
Calathea Drechslera setariae 59 70
Chrysanthemum Fusarium oxysporum 81 90
Pseudomonas cichorii
Dianthus Gibberella zeae 70 75
Dieffenbachia Myrothecium roridum 70- 81

Xanthomonas campestris
pv. dieffenbachia
Dracaena Fusarium moniliforme 70 81
Epipremnum Rhizoctonia solani 68 86
Hedera Xanthomonas campestris pv. 68 86
Hibiscus Pseudomonas cichorii 59 74

Pseudomonas syringae pv.
Xanthomonas campestris pv. 75 91
Impatiens Pseudomonas syringae 70- 86

Rhizoctonia solani 68 95
Nephrolepis Rhizoctonia solani air less than 95
soil less than 90

iamoe L. upumai temperatures ior some uaseases 0 o rnameniais arranged oy plant.
Optimal air
Plant Pathogen range (*F)
Pelargonium Pseudomonas cichorii 68 82

Pseudomonas solanacearum 72 95

Xanthomonas campestris pv. 77 86
Philodendron Erwinia chrysanthemi 82 93
Schlumbergera Drechslera cactivora 75 91
Spathiphyllum Cylindrocladium spathiphylli 70 81
Strelitzia Xanthomonas campestris 70 81
Syngonium Myrothecium roridum 59 81

Xanthomonas campestris 79 86
pv. dieffenbachiae
Zinnia Xanthomonas campestris 70 84
pv. zinniae