27661 - Plant pathology in agroforestal system

Learning outcomes

Students will acquire knowledge on: 1) general bases of plant diseases caused by biotic and abiotic agents; 2) measurement tools of disease; 3) measurement tools of pathogens 4) most important disease epidemiology, 5) principles of disease control.

Course contents

A) Prerequisites

Students attending this course must have good knowledge of microbiology, plant biology and physiology. Such skills are provided by the courses of the first and second years.

B) Teaching Units

The course includes two teaching units

1. General plant pathology

2 Plant diseases

1. General plant pathology (total teaching unit 30 hours)

Introduction to plant pathology (2 hours) – Brief background history of plant diseases. Economic and social importance of plant diseases.

Disease and pathogenesis concept (8 hours) - Definition of plant and crop disease. Abiotic and biotic diseases (infectious). Pyramid of the disease. Cycle of an infectious disease: inoculation (penetration), infection (multiplication), evasion and dissemination. Diagnosis of plant diseases. Koch’s postulates. Overview of epidemiology: monocyclic, polycyclic and polyetic diseases.

Pathogens (10 hours) - Main features (morphological, biochemical and biological) of fungi, oomycetes, bacteria, viruses and nematodes. Diagnostic techniques for oforest pathogens. Overview of pathogenesis and mechanisms of plant resistance to pathogens.

Plant- pathogen interactions. How pathogens attack plants and how plants defend themselves (preexisting and induced defences) (3 hours)

Plant protection at the international, national and regional level. Concept of quarantine organism and phytosanitary certification. Climate change and plant diseases (3 hours).

Elements of agronomic, chemical, physical, biological fight against plant diseases in a context of environmental sustainability (2 hours).

Abiotic diseases and alterations - Classification and importance of abiotic stresses (thermal, water, nutritional and extreme atmospheric events) and symptoms (2 hours).

Knowledge acquired in the teaching unit 1:

Plant pathology language

Different models of plant pathogens and their main characteristics.

Disease cycle in relation to pathogen, environmental factors and vegetative plant stage.

Measurement of plant disease

Principles of disease control

2. Plant diseases (total teaching unit 20 hours)

Economic importance, distribution, symptoms, epidemiology and control measures will be described for each disease.

Cereals diseases (5 hours): Head blight (Fusarium spp.), Foot and root rot (Gaeumannomyces graminis tritici, Rhizoctonia cerealis, Pseudocercosporella herpotrichoides), Rusts (Puccinia spp.), Powdery mildew (Erysiphe graminis f. sp. tritici).

Ornamental and forest tree diseases (5 hours): Dutch elm disease (Ophiostoma ulmi and O. novo-ulmi), canker stain of plane (Ceratocystis fimbriata f. sp. platani), chestnut blight (Chryphonectria parasitica), wood decay, Armillaria root rot (Armillaria mellea), white root rot (Rosellinia necatrix) and crown rot (Phytophtora cactorum)

Vegetable diseases (5 hours): Lettuce downy mildew (Bremia lactucae), Potato and tomato late blight (Phytophthora infestans), Tracheomycosis (Fusarium oxysporum , Verticillium dahliae, V. lecanii), Bacterial leaf spot of tomato (Xanthomonas campestris pv. vesicatoria), mosaico del pomodoro (Tomato Mosaic Virus, ToMV) .

Grapevine diseases (5 hours): Downy mildew (Plasmopara viticola),grey mould (Botryotinia fuckeriana, an. Botrytis cinerea), powdery mildew (Uncinula necator, an. Oidium tuckeri), yellows disease .

Teaching support activity (10 hours)

Activity in lecture rooms (2 hrs)

Seminars, projection of educational movies, plant samples examination, assessment of disease severity by using specific scales

Laboratory activity (6 hrs)

Plant pathology lab knowledge, isolation of pathogens from plant tissue, identification at optical and stereo microscope of pathogen propagules

Field activity (2 hrs)

assessment of disease symptoms at the University experimental farm or other farms. Assessment of the phytosanitary status of ornamental trees.

Readings/Bibliography

Agrios G.N. (2005) Plant Pathology, Academic Press (USA)

Belli G. (2006). Elementi di Patologia Vegetale, Piccin Editore

Capretti P e Ragazzi A. (2009). Elementi di Patologia Forestale, Patron editore

Moriondo F. (1999). Introduzione alla patologia forestale, UTET

Teaching methods

1. Class lectures

2. Practical activity: the student will be directly involved in general practices commonly used in a laboratory of plant pathology in order to practically apply the theoretical knowledge acquired during lessons.

3. Guided tours: student will be accompanied in guided tours to experimental farms

Assessment methods

Verification of learning takes place in the sessions reported on Almaesami, through a written test lasting 40 minutes, concerning the entire program of both modules, without the help of notes or books. It consists of 26 questions, partly multiple choice and partly open-ended. Each question is awarded a maximum of one point. In the same session, students who have passed the written exam will be admitted to an interview to discuss with the teachers the answers provided in the assignment and deep some of the topics listed. In this phase, a further 4 points and eventually “laude” may be awarded.

Teaching tools

Lessons are held with PowerPoint presentations, educational films and the use of laboratory tools

Office hours

See the website of Riccardo Baroncelli

See the website of Elena Baraldi