College of Agriculture and Life Sciences
Department of Plant Pathology


Ornamental crops, which include floriculture and nursery products, have been the fastest growing agricultural sector in North Carolina over the last decade. This colorful and diverse industry accounts for the highest percentage of total crop sales in the state surpassing traditional crops such as tobacco and cotton. North Carolina produced $841million worth of nursery and greenhouse crops in 2002 making it the eighth largest producer of floriculture crops and fifth largest producer of nursery crops in the United States. Floriculture crops include bedding/garden plants, perennials, cut flowers, potted flowering plants, and indoor foliage plants. Nursery crops include shrubs and trees, including broadleaf and coniferous evergreens, deciduous shade and flowering trees, and Christmas trees.

Because the value of ornamental horticulture products is derived from their appearance and size, market expectations for plant quality are very high and tolerances for pest damage are very low. Disease management in ornamental crop production can be extremely difficult. It is not uncommon to have 300 different plant species growing in one nursery. And to a large extent, crop production practices encourage the development and rapid spread of plant diseases. In both nursery and greenhouse production, plants tend to be tightly spaced to maximize the available growing space. Overhead irrigation is also a common practice. Both of these conditions contribute to creating an environment (high humidity, prolonged leaf wetness, poor light penetration) that is highly conducive to disease development of plant pathogens. Because disease development can be swift under these conditions, rapid diagnosis of plant problems is critical.

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, ornamental crop production in North Carolina is faced with the constant threat of introducing exotic or regulated pathogens into our state on infested plant material or in potting substrates.

Some additional web sites:

More information about disease in ornamentals is availble from the Plant Disease and Insect Clinic.