Ornamental crops, which include floriculture and nursery products, have been the fastest growing agricultural sector in North Carolina over the last decade. However, nurseries and greenhouses are not isolated geographically, and the movement of both propagation and finished stock occurs across the globe. Due to this movement of plant material, North Carolina is faced with the constant threat regarding the introduction of exotic or regulated pathogens into our state on infested plant material or in potting substrates.

The foundation of all disease management programs in commercial floriculture and nursery crops is integrated pest management, better known as IPM. For ornamentals, IPM starts with good sanitation practices that eradicate and prevent movement of pathogen inoculum in the crop production system. Inspecting buy-ins for symptoms of plant disease is a key step in an established IPM program. Maintaining stock plants for propagation that are pathogen free ensures the perfect start to an IPM plan. Removing crop debris after sales and disinfesting surfaces in production areas are two examples of sanitation in practice. Sanitation is one of the most critical steps in IPM because it eliminates pathogen inoculum. Cultural practices that avoid moving plant pathogens through the production system, such as treatment of irrigation water, is another good IPM practice. Avoiding the re-use of untreated propagation trays, flats and pots that are proven carriers of pathogens like Rhizoctonia, Phytophthora, and Thielaviopsis from previous crops can eliminate sources of pathogen inoculum. Some plant viruses are systemic in their host so any hand planting, trimming, or just picking up a plant to move it can result in the worker or tool moving the virus to a healthy crop. Finally, many fungal and bacterial plant diseases can be prevented in ornamental crops by following good IPM practices and combining them with the use of preventative fungicide and bactericide applications. Many products are commercially available; please refer to the Ornamental Chemical Control for NC below.

Boxwood Blight Management:

Boxwood Blight Research:

Commercial Nursery Information:

Christmas, Forest, and Landscape Tree Information:

Floriculture Information:

Landscape Information:

Nursery Crops Information:

Questions regarding disease problems in commercial floriculture, nursery crops and Christmas trees should be directed to the Plant Disease and Insect Clinic, NC State University: http://www.cals.ncsu.edu/plantpath/extension/clinic/index.html

Disease Factsheets

Phytophthora root rot on Fraser fir NCSU Factsheet

Rose diseases and their control in the home garden NCSU Factsheet

Powdery mildew of ornamentals and shade trees NCSU Factsheet

Nematodes and their control in woody ornamentals in the nursery NCSU Factsheet

Nematodes and their control in woody ornamentals in the landscape NCSU Factsheet

Pine wood nematode NCSU Factsheet

Holly diseases and their control in the landscape NCSU Factsheet

Slime flux/wet wood NCSU Factsheet

Southern bacterial wilt on marigolds NCSU Factsheet

Scorch diseases on shade trees NCSU Factsheet

Entomosporium leaf spot on red tip NCSU Factsheet

Rhododendron diseases NCSU Factsheet

Phytophthora root rot and its control on woody ornamentals NCSU Factsheet

Damping-off in flower seedbeds NCSU Factsheet

Juniper diseases and their control in the landscape NCSU Factsheet

Azalea diseases and their control NCSU Factsheet

Diseases of Leyland Cypress NCSU Factsheet

Dutch elm disease NCSU Factsheet

Common pine diseases and their control NCSU Factsheet

Common diseases of gold-dust plant NCSU Factsheet

Dogwood diseases NCSU Factsheet

Root and butt rot of oaks NCSU Factsheet

Nematode management in bedding plants NCSU Factsheet

Phytophthora crown and root rot in landscape ornamentals NCSU Factsheet

Sanitizers recommended for ornamental plant production NCSU Factsheet

Written By

Dr. Mike BensonProfessor Emeritus (919) 515-2730 (Office) mike_benson@ncsu.eduEntomology and Plant Pathology - NC State University

Contributing Specialist

Photo of Dr. Kelly IvorsDr. Kelly IvorsAssociate Professor and Extension Specialist (828) 684-3562 kelly_ivors@ncsu.eduEntomology and Plant Pathology - NC State University
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