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

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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.