Basic concepts on the most important diseases in the nurseries and in urban context. Concept of disease. The disease triangle. The inoculum. Strategies of attack by the pathogens and plant defense mechanisms. Symptoms. Koch’s postulates. Nursery diseases. Foliage diseases. Root diseases. Vascular diseases. Cankers. Wood decay. Rusts.Disease control: agronomic, physical, chemical, biological, genetic; legislative control.
Panconesi A., Moricca S., Ragazzi A., Dellavalle I., Tiberi R. – Parassiti delle piante arboree forestali ed ornamentali. Specie introdotte e di temuta introduzione. Pàtron Editore, Bologna, 2014, 447 pp. ISBN 9788855532198
Capretti P., Ragazzi, A. (2009) – Elementi di Patologia Forestale. Patron Editore, Bologna.
Jones, R.K., Benson, D. M. – Diseases of woody ornamentals and trees in nurseries. APS Press, 2001
Moriondo F., Capretti A. e Ragazzi A. (2006) – Malattie delle piante in bosco, in vivaio e delle alberature. Patron Editore, Bologna.
Scientific articles on specific themes and electronic material provided by the teacher
Learning Objectives
To provide student with basic knowledge on the major diseases and disorders of ornamentals and nursery plants.
Prerequisites
Students are expected to be familiar with Botany, Microbiology, Arboriculture and Urban Silviculture
Courses recommmended: Botany, Microbiology, Arboriculture, Urban Silviculture.
Teaching Methods
Frontal classes. Laboratory and field exercises. Guided tours.
Further information
Classes, exercises and lab attendance non mandatory but strongly recommended.
Teaching tools: video projector, PC, overhead projector, experimental fields, labs
Type of Assessment
Oral examination
Course program
Introduction to plant pathology. Historical overview. Concepts of: disease; epidemics; endemic; pandemic. Causes of plant diseases: biotic diseases (damage by fungi, bacteria, viruses, viroids, phytoplasmas, protozoa) abiotic disorders (damage caused by adverse soil or environmental conditions; air pollution damage). Disease triangle. The inoculum (typeof inoculum; inoculum production and dispersal; inoculum survival). Pathogens’ attack strategies and plant defense mechanisms. The infection process (pre-penetration; penetration; colonization; host evasion). Pathogenesis. Symptoms. Damage caused by physical and mechanical causes: wounds. The diagnostic process (visual inspection, microscopic diagnosis). Koch's postulates. Parasitism. Saprophytism. Commensalism. Endophytism. Mutualism. Types of symbiosis (mutualistic, neutral, antagonistic). Plant disease epidemiology (incidence and severity of the disease; monocyclic and polycyclic diseases; epidemic rate; disease progress curves; epidemics forecasting). The most important and frequent diseases in the nursery (seedlings’ damping-off; other diseases of seedlings in the herbaceous stage; shoot infectious diseases). Plant disease management in the urban environment. The impact of environmental conditions on disease development in the nursery. Classification of diseases in relation to the plant organ affected: leaf diseases; root diseases; vascular diseases; canker diseases,; root rot, rusts. For each disease type, one or more pathogens – selected among the most damaging - are taken into account as model(s), illustrating their biological cycle. Phytosanitary hygiene and control measures. Agronomic, physical, chemical, biological, genetic and legislative control strategies. Peculiarities of the nursery activity and risk of spreading disease over the territory. The importance and procedures of phytosanitary inspection of import-export plant material. Quarantine. Mandatory quarantine regulations. Phytosanitary certification and phytosanitary plant passport. Integrated disease management.
Exercises
Field trips, including visits to parks, nurseries, gardens and tree lines. Inspection of infected material in the field and in the laboratory, with symptom analysis. Preparation of humid chambers. Microscopic observation of fungal reproductive structures. Preparation of nutrient media. Isolation and identification of pathogens from infected plant samples.