ACES Publications

Author:
PubID: ANR-0401
Title: Disease & Insect Control For Roses
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ANR-401 Disease And Insect Control For Roses

ANR-401, Reprinted Oct. 1996. Patricia P. Cobb, Extension Entomologist, Professor, Entomology, and Austin K. Hagan, Extension Plant Pathologist, Professor, Plant Pathology, both at Auburn University


Disease And Insect Control For Roses
Disease control is an important part of maintaining beautiful and healthy roses. Homeowners will have to contend with black spot and powdery mildew on their roses almost every year. Regular fungicide applications are needed to control both of these diseases. These treatments should also control Botrytis blight and other foliage diseases.

Protecting the foliage from early spring infections is the key to season-long black spot and powdery mildew control. To accomplish this goal, begin fungicide spray programs shortly after budbreak and continue at regular intervals until the first hard frost.

Generally, you should make fungicide applications at 10- to 14-day intervals during dry weather, depending on the fungicide used. During rainy weather, a 5- to 7-day interval between applications may be needed to maintain disease control. See Table 1 for specific spray intervals for recommended fungicides.

Table 1. Disease Control For Roses.

Disease / Chemical Rate Of Application Comments
Per Gal. Per 100 Gal.
Blackspot 1 T.
1 T.
1 lb.
1 lb.
Apply at budbreak. Repeat at 7- to 14-day intervals until frost. For best results, stay on 7-day spray intervals. Shorten spray intervals during wet weather. Chlorothalonil and folpet may scorch foliage during summer.
benomyl
BENLATE 50W
TERSN 1991 50W
chlorothalonil
BRAVO 4.17F
DACONIL 2787
DACONIL 2787 75W
DACONIL MULTIPURPOSE
FUNGICIDE 29.6F
2 t.
2 t.
2-1/2 t.

2-1/4 t.
2 pt.
2 pt.
1-1/2 lb.
folpet
PHALTAN 75W
FOLPET 50W
1 T.
1-2 T.

1-2 lb.
mancozeb
DITHANE M-45, 80W
FORE 80W
2 t.
2 t.
1-1/2 lb.
1-1/2 lb.
triforine
FUNGINEX ROSE
DISEASE CONTROL 6.5 E
TRIFORINE 18.2E
 1 T. 12-18 fl. oz.
Botrytis Blight 1/2 T.
1/2 T.
1/2 lb.
1/2 lb.
Regular blackspot sprays should control botrytis blight. Shorten spray intervals to 7 days for best protection. Remove blighted blooms and shoots. Problems occur during wet, overcast weather.
benomyl
BENLATE 50W
TERSAN 1991 50W
chlorothalonil
BRAVO 4.17F
DACONIL 2787 4.17F
DACONIL 2787 75W
2 t.
2 t.
2-1/2 t.
2 pt.
2 pt.
1-1/2 lb.
iprodione
CHIPCO 26019 50W
  1-2 lb.
DCNA
BOTRAN 75W
  1/2 - 3/4 lb.
thiophanate-methyl + mancozeb
ZYBAN 75W
DUOSAN 75W
2-1/2 t.
2-1/2 t.
1-1/2 lb.
1-1/2 lb.
Powdery Mildew 1/2 T.
1/2 T.
  1/2 lb.
1/2 lb.
Regular blackspot sprays should control powdery mildew. Otherwise, apply at first sign of disease and repeat at 5- to 14-day intervals.








Milban is a RESTRICTED USE pesticide.


Rubigan may affect leaf growth during cool, overcast weather.
benomyl
BENLATE 50W
TERSAN 1991 50W
copper oleate
POWDERY MILDEW CONTROL 15S
1 T.
dinocap
KARATHANE WD 19.5W
2/3 T. 6-8 oz.
dodemorph
MILBAN 39E
1 qt.  
fenarimol
RUBIGAN A.S. 1.0E
  4-12 fl. oz.
triadimefon
BAYLETON 25W
1/10-1/5 t. 2-4 oz.
triforine
FUNGINEX ROSE
DISEASE CONTROL 6.5E
TRIFORINE 18.2E
1 T. 1-1/2 pt.
12-18 fl. oz.
Canker     Maintain good plant vigor. Prune out diseased canes. Use dormant spray of lime-sulfur.
None labeled
Crown Gall     Refer to label for directions. Root-dip for bare-root stock. Effectiveness my be limited. Destroy infected plants. Replace with crown gall-resistant ornamentals.
Agrobacterium radiobactor Strain 84. See comments
NORBAC 84
GALLTROL

To ensure complete coverage of the foliage, spray roses until the fungicide drips off the leaves. Fungicide performance may be improved by adding a commercially available spreader-sticker or liquid detergent (1/2 tablespoon per gallon).

Chlorothalonil and folpet may burn the leaves of some rose varieties, especially at temperatures above 90 degrees F. To avoid this problem, use either of these fungicides at half the label rate and mix them with Benlate at 1/2 tablespoon per gallon. There are no controls for existing crown gall infections. Fumigate infested areas before replanting with roses or other woody ornamentals. Root dips of Galltrol or a similar product may be used at planting to protect roses for short periods of time.

Good sanitation practices can reduce disease problems. When buying new roses, select only disease-free bushes. Remove and destroy any plants damaged by crown gall. Carefully prune out any stem cankers on roses in late winter and place fresh mulch around the plants.

Lime sulfur (1:15 dilution) applied in late winter when the roses are dormant will also help reduce early season powdery mildew problems. Always surface irrigate roses to avoid spreading black spot and other diseases.


Mite And Insect Control

The recommendations in Table 2 are for controlling some common pests that feed on roses. Well-kept, healthy plants may not be less susceptible to insect attack, but they may recover more quickly from insect damage. Regular and thorough inspection of plants is essential if pests are to be controlled at a low infestation level.

Table 2. Insect Control For Roses.

Pest Pesticide Amount To Use Per
Gallon Or As Stated
Comments
Aphids acephate
ORTHENE Turf, Tree
and Ornamental Spray
2 t. Begin treatment when aphids first attack plants early in the spring. Repeat as needed.
diazinon
25EC
2 t.  
dimethoate
CYGON 2E
2 t.  
malathon
57EC
1 T.  
Caterpillars


(Bacillus thuringiensis)
carbaryl*
SEVIN 50WP
SEVIN 5D

DIPEL THURICIDE
2 T.
See comments

See Comments
Treat when young larvae are present.

Dust lightly but thoroughly

See label.
Bud, blossom, and leaf-feeding beetles carbaryl*
SEVIN 50WP
SEVIN 5D
2 T.
See Comments
Treat as needed.

Dust lightly but thoroughly.
malathion
57EC1
T.  
Spider Mites insecticidal soap 50.5EC 4 oz. Follow label directions
dicofol
KELTHANE 18.5EC
2 t. Keep area free of weeds. Direct spray to underside of leaves. Repeat treatment every two weeks as needed. Alternate chemicals once or twice during the season.
insecticidal oil,
such as
SunSpray ULTRA Fine
  Use oils only under conditions listed on the label.
dienochlor
PENTAC 50W
PENTAC AQUAFLOW
2 t.
2/3 t.
Repeat treatment every 28 days as needed.
Thrips acephate
ORTHENE Turf, Tree
and Ornamental Spray
1 T. Destroy old rose blossoms. Treat every 3 to 5 days as needed.
diazinon
25EC
2 t.  
dimethoate
CYGON 2E
2 t.  
* Watch for buildup of spider mites if carbaryl is used when mites are present.
T. = tablespoon
t. = teaspoon

Proper pest identification is necessary to know which chemical to apply as well as the proper application time. When spraying, thorough coverage is important in controlling rose pests. Apply pesticides only according to label directions and only when pests are present. Read the entire label.


Use pesticides only according to the directions on the label. Follow all directions, precautions, and restrictions that are listed. Do not use pesticides on plants that are not listed on the label.
The pesticide rates in this publication are recommended only if they are registered with the Environmental Protection Agency and the Alabama Department of Agriculture and Industries. If a registration is changed or cancelled, the rate listed here is no longer recommended. Before you apply any pesticide, check with your county Extension agent for the latest information.

Trade names are used only to give specific information. The Alabama Cooperative Extension System does not endorse or guarantee any product and does not recommend one product instead of another that might be similar.
For more information, contact your county Extension office. Look in your telephone directory under your county's name to find the number.

For more information, contact your county Extension office. Visit http://www.aces.edu/counties or look in your telephone directory under your county's name to find contact information.


Published by the Alabama Cooperative Extension System (Alabama A&M University and Auburn University), an equal opportunity educator and employer.


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