27342 - Plant Pathology and Pathometry

Learning outcomes

Students will acquire knowledge on: 1) the general bases of plant diseases caused by biotic and abiotic agents; 2) major infective crop diseases with severe economic impact; 3) the measurement of disease symptoms; 4) principle of disease control in according to the recent legislation of integrated or biological disease management.

Course contents

A) Prerequisites

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

B) Teaching Units

1. General plant pathology
2. Plant disease measurement
3. Principles of disease control
4. Plant diseases

1. General plant pathology (total teaching unit 10 hours)

Introduction to plant pathology (1 hours) - Background history. Disease definition and the concept of plant disease. Economic and social importance of plant disease.

Pathogenesis (2 hours) - Biotrophic and necrotrophic pathogens. Disease cycle: inoculation, infection, production and dispersal of inoculum. Symptomatology.

Pathogens (6 hours) - Morphological, biochemical and biological features of fungi, bacteria, oomycetes, viruses, and phytoplasmas. Fungal and bacterial toxins. How pathogens attack plants and how plants defend themselves against pathogens (preexisting and induced defences). Main diseases symptoms, identification and diagnosis.

Abiotic stresses (1 hours) – classification and importance of environmental factors that cause plant diseases and disorders.

Knowledge acquired in the teaching unit 1:

Specific terms to use in plant disease description.

Different type of plant pathogens and main characteristics.

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

Main diseases and alterations caused by abtiotic factors.

2. Plant disease measurement (4 hours)

Measurement of disease and yield loss. Incidence, severity and economic threshold of the disease.

Knowledge acquired in the teaching unit 2:

Calculation of disease incidence and severity.

Yield loss determination in relation to the main diseases.

3. Principles of disease control (6 hours)

Importance of plant disease control in relation to economic and environmental sustainability and to healthy crops. Possibility to reduce disease severity by action on the pathogen, the environment and on the plant. Specific terms to use in plant disease control. Control methods: agronomical, chemical, physical and biological measures. Concept of integrated and biological disease managements. Short background on the law rules of plant protection products.

Knowledge acquired in the teaching unit 3:

Principles of plant disease control.

Different control methods.

Principles of integrated and biological disease managements.

4. Plant diseases (16 hours)

This part develops disease importance, distribution, symptoms, epidemiology and control measures.

• Grapevine diseases (2 hours)

Downy mildew (Plasmopara viticola), grey mold (Botryotinia fuckeriana, an. Botrytis cinerea), powdery mildew (Uncinula necator, an. Oidium tuckeri), yellows disease and blackwood disease by phytoplasmas.

• Pome fruit diseases (2 hours)

  Apple scab (Venturia inaequalis, an. Spilocaea pomi), apple powdery mildew (Podosphaera leucotricha, an. Oidium farinosum), pear brown spot (Pleospora herbarum, an. Stemphylium vesicarium), pear bark canker (Valsa ceratosperma, an. Cytospora vitis), fire blight (Erwinia amylovora).

• Stone fruit diseases (2 hours)

  Peach leaf curl (Taphrina deformans), twig cankers (Fusicoccum amygdali, syn. Phomopsis amygdali), brown rot (Monilinia spp., an. Monilia), bacterial spot (Xantomonas arboricola pv. pruni), Sharka (Plum Pox Virus, PPV).

• Olive tree diseases (0.5 hour)

  Xilella fastidiosa.

• Kiwifruit diseases (0.5 hour)

  Bacterial canker PSA (Pseudomonas syringae pv. actinidiae), fungal wood decay.

• Strawberry diseases (1 hours)

  Grey mold (Botryotinia fuckeriana, an. Botrytis cinerea), anthracnose (Colletotrichum spp.), bacterial angular leaf spot (Xanthomonas fragariae).

• Vegetable diseases (2 hours)

  Lettuce downy mildew (Bremia lactucae), potato and tomato late blight (Phytophthora infestans), tracheomycosis (Fusarium oxysporum f.sp., Verticillium dahliae, V. lecanii), bacterial leaf spot of tomato (Xanthomonas campestris pv. vesicatoria), mosaico del pomodoro (Tomato Mosaic Virus, ToMV).

• Cereal diseases (1 hours)

  Fusarium head blight (Fusarium spp.), foot rot (Gaeumannomyces graminis tritici, Rhizoctonia cerealis, Pseudocercosporella herpotrichoides), rusts (Puccinia spp.) and powdery mildew (Erysiphe graminis f. sp. tritici).

• Ornamental tree diseases (2 hours)

  Dutch elm disease (Ophiostoma ulmi and O. novoulmi), canker stain of plane (Ceratocystis fimbriata sp. f. sp. platani), chestnut blight (Chryphonectria parasitica), fungal wood decay.

• Root diseases of trees (1 hour)

  Armillaria root rot (Armillaria mellea, sin. Armillariella mellea), white root rot (Rosellinia necatrix) and crown rot (Phytophtora cactorum).

• Abiotic stresses (2 hours)

Caused by heat, cold, drought and nutritional stresses and by extreme environmental factors such as hail, strong wind, air pollution.

Knowledge acquired in the teaching unit 4:

Symptoms of the main diseases and abiotic stresses of agricultural and ornamental plants.

Disease epidemiology.

Disease control measures.

Teaching support activity (24 hours)

Activity in lecture rooms

1) Training seminars.

2) Projection of educational movies.

3) Plant samples showing disease symptoms.

4) Assessment of disease severity by using specific scales.

5) Reading and discussion of fungicide product labels and safety sheet.

Laboratory activity

1) Fungal pathogens recognition at optical microscope.

2) Disease control strategies and fungicides allowed for the application on plants and their characteristics.

3) At the end of the activity, students will be invited to write a brief report.

Field activity

1) Assessment of disease symptoms at the agricultural garden of the Dipsa, at the University experimental farm in Cadriano (BO) and at other farms.

2) Assessment of the phytosanitary status of ornamental trees.

Consolidation activity

This part of the course will be dedicated to the consolidation of the knowledge provided during the lessons, with particular attention to the needings raised by the students.

Readings/Bibliography

• Belli G. (2012). Elementi di Patologia Vegetale, Piccin Editore, ISBN: 8829921297.
• Agrios G.N. (2005) Plant Pathology, Academic Press (USA), ISBN: 9780120445653 - This textbook can be used by students who wish to make the oral exam in English.
• Lorenzini G. & Nali C. ‘Principi di Fitoiatria’, 2012, Edagricole Bologna, ISBN: 8850653883.
• Monographs

Teaching material will be upload in the "Teaching staff-student distribution list". At the beginning of the lessons, the students will receive the name of the distribution list and the password to download the teaching material. Students are required to register to the list at the beginning of the lessons. 

Teaching methods

1) Class lectures

Knowledge acquirement a) necessary to understand the general characteristics of fungi, bacteria, viruses and phytoplasmas pathogens of agricultural and ornamental plants; b) principles of integrated and biological disease control; c) of the methods to measure plant diseases; d)  on the main abiotic stresses. 

This knowledge will be monitored during the course through a continuous interaction between teacher and student. This will possibly involve also the discussion of some interesting papers on the main topics covered during the lessons. This will allow to stimulate the critical sense communication skills of the student.

2) Practical activity

Learning of: a) observation and assessment of disease symptoms; b) general practices commonly used in a laboratory of plant pathology and crop protection; c) consultation of databases ad web sites to plan disease managements and to learn the key aspects of plant protection products, in order to practically apply the theoretical knowledge acquired during lessons.

3) Guided tours

Student will be accompanied in guided tours to the agricultural field of University, in Cadriano (BO) and in local farms in order to examine plant diseases symptoms.

Assessment methods

Written exams (in Italian only) or oral exams in Italian (or in English upon prior request) on the topics covered during the course. In particular two written exams (June and July) and five oral ones (one in July, one in September, one in December and one in January/February). Exam dates will be listed in Alma esami and in the hompage of the teacher in the "latest news" section. The written exam consist of 30 closed questions plus 2 open questions. In the oral examination the student will be evaluated on at least three questions.

Teaching tools

Overhead projector and personal computer will be used for class lectures.

Laboratory exercises will take place in the Teaching laboratories of 

•  Biology I - 1st floor – North Wing, n. 46.
• ICT and multimedia – 1st floor – North Wing, n. 44-46.

Office hours

See the website of Roberta Roberti