How to Manage Pests

UC Pest Management Guidelines

Chlorothalonil (Daconil) is effective for the control of Botrytis spp., Alternaria spp., Rhizoctonia spp., as well as other leaf-spotting fungi on many ornamentals.

Fenarimol (Rubigan) is a systemic fungicide used for prevention or eradication of powdery mildew on roses and field and container-grown ornamentals.

Fenhexamide (Decree) applied as a foliar or floral spray is very effective against Botrytis.

Fixed copper (Kocide, BlueShield, Champ) is a general purpose fungicide and bactericide most often used as protectant against various leaf-spot pathogens, Botrytis spp., and anthracnose. Overall growth of some plants may be reduced by this material; follow label directions carefully to reduce the risk of phytotoxicity.

Fosetyl-Al (Aliette) is active against Phytophthora species and some Pythium species. It is most effective when applied as a foliar spray because of its reverse systemic action: when sprayed on foliage it moves into the plant and is transported to the roots, providing better control than a soil application.

Lime sulfur is a powdery mildew eradicant. Apply this material with caution when temperatures exceed 85° F. Because it is toxic to green plants, it is best used as a dormant spray.

Mancozeb (Dithane) is a dithiocarbamate fungicide used to protect against leaf spots, Botrytis, rusts, and blight. It is not systemic so thorough coverage is important for control.

Myclobutanil (Systhane) is a systemic fungicide applied as a foliar spray that is both a protectant and eradicant of rusts or powdery mildew on carnations, crepe myrtle, gerbera, roses, and snapdragons. It also controls Cercospora leaf spot. It is an important tool in the eradication program for chrysanthemum white rust.

Neem oil (Triact) is a broad-spectrum botanical pesticide derived from the neem tree that is effective against various fungal diseases including black spot on roses, powdery mildew, downy mildew, anthracnose, and leaf spot.

Piperalin (Pipron) is a foliar spray that eradicates powdery mildew on rose, lilac, dahlia, phlox, zinnia, chrysanthemum, and catalpa.

Potassium bicarbonate (Kaligreen) can be used to protect against powdery mildew infections on roses. Because it is a contact-type fungicide, thorough coverage is essential for good protection.

Propiconazole (Banner Maxx) is a preventative fungicide against powdery mildews, rusts, leaf spots, and blights.

Stylet oil (JMS Stylet Oil) is available to control black spot and powdery mildew on roses, poinsettia, chrysanthemum, diffenbachia, and philodendron. There have been some phytotoxicity problems with this material, especially on greenhouse roses.

Thiophanate methyl (FungoFlo, Cleary's 3336F, etc.) is a systemic fungicide that is used to control many leaf-infecting fungi and some soilborne fungi.

Triadimefon (Strike) is a long-lasting systemic fungicide used for general control of some powdery mildews, some rusts, and leaf blight and spots in greenhouses and commercial nurseries.

Wettable sulfur can be used as a spray to protect ornamentals against powdery mildew. It has no eradication action and it leaves a residue on plants that could cause plant injury. Apply this material with caution when temperatures exceed 85° F.

PUBLICATION

UC IPM Pest Management Guidelines: Floriculture and Ornamental Nurseries
UC ANR Publication 3392
Diseases
R. D. Raabe (emeritus), Environmental Science, Policy, and Management (ESPM), UC Berkeley
M. E. Grebus, Plant Pathology, UC Riverside
C. A. Wilen, UC IPM Program, UC Cooperative Extension, San Diego Co.
A. H. McCain (emeritus), Environmental Science, Policy, and Management (ESPM), UC Berkeley

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