Plant Nursery Diseases
Nurseries are used to grow and propagate plants. While some nurseries specialize in only flowers and plants, others grow trees and shrubs. Nursery plants are often grown in greenhouses, which are glass or plastic buildings designed to protect young plants from adverse weather conditions. One of the greatest challenges of nursery or greenhouse caretakers is fighting the many types of diseases that can afflict plants.
Crown and Root Rot
Plants most susceptible to crown and root rot include gerbera daisies, pansies and gloxinias. Although the disease can occur at any stage of growth, it typically attacks after flowering begins. Symptoms are stunted growth and off-color foliage. The disease causes a plant to wilt rapidly where a plant appears healthy one day, but then suddenly wilts and declines. Crown and root rot can be spread by overhead watering which splashes the pathogen to other plants.
Southern wilt, which particularly attacks geranium producers, is most common in the southeastern region of the United States. Symptoms of the disease include the lower leaves wilting which improve overnight only to reoccur the following day. The wilt spreads up the plant, leading to its eventual death. Other symptoms are brown vascular discoloration that’s visible on stems.
Black Root Rot
Black root rot causes considerable loss in greenhouse plants, with pansies and vincas being the most vulnerable for the disease. Because the fungus of black root disease damages a plant’s root, it hinders the root from absorbing nutrients. This root injury causes plants to show symptoms of nutritional stress, such as the yellowing of younger growth. Rather than a healthy white color, the roots of infected plants range from off-white or gray to black, depending on the severity and stage of the disease.
Aerial blight, which causes intense damage to a plant’s aerial portion, is a serious disease which mainly afflicts vincas. The first signs of aerial blight occur on leaves which begin to rapidly collapse. Next the infection hits the leaf petiole in the area where it’s attached to the plant stem. The fungus continues growing to the plant’s base, resulting in death if wet conditions continue.
Bacterial blight can wipe out an entire crop of plants with the most endangered ones including begonias, geraniums and zinnias. Water-soaked leaf spotting, along with the browning of leaf margins, is an initial symptom. Other symptoms are inverted “V” patterns developing. The next symptom is lesions turning copper in color as the disease progresses. Leaf collapse, followed by plant wilting and more plant decline, are continuing symptoms.
Impatiens Necrotic Spot Virus
Impatiens necrotic spot virus, known as INSV, is one of the more severe diseases affecting nursery crops. Chrysanthemums, begonias, exacum, impatiens, vincas and gloxinias are some of the plants most at risk. The disease is mostly carried by tiny insects called thrips. INSV has various symptoms such as black ring spots which afflict impatiens. Other symptoms include black foliar lesions and stem lesions. Symptoms usually depend on the stage of the disease and other cultural variables.