84587 - Control Of Disease In Organic Plant Production

Learning outcomes

CONTROL OF DISEASES IN ORGANIC PLANT PRODUCTION

The aim of this course is to provide an overview of the current scientific knowledge about different organic approaches to regulate diseases, restricting to a minimum pesticides use without losing a high nutritional quality of the production and an adequate return and satisfaction to the producers. A special attention will be posed to the production of high-quality, disease-free, vegetative propagation material.

Course contents

MODULE 1 - GENERAL ASPECTS

1.General principles of organic plant production (18 HOURS)

General aspects and elements of epidemiology: organic and biodynamic agriculture, goals of conventional, low-input and organic agriculture (o.a.), allowed, restricted and prohibited fertilizers and pesticides in o.a, trends of organic production and unresolved problems for organic growers; development of epidemics: range of pathogens, the disease cycle, dissemination by air, water, vectors and humans, overwintering of pathogens.

General management of diseases in organic agriculture: biodiversity enhancement, consequences of monoculture and uniformity within species, mechanisms by which biodiversity can reduce biotic and abiotic stresses in both phyllo- and rhizosphere; other general practices: crop rotation, choice of rotation crops and their sequences, soil health management, composts and manures in o.a., green manure, general tillage decisions, water management in organic systems and effects on foliar and soilborne diseases, problems due to soil erosion and mismanagement of irrigation water.

Preventive control options: regulatory control methods, inspections, quarantines and crop eradication, Xylella fastidiosa and tomato ringspot virus: two examples of quarantine pathogens in Italy, control methods that mechanically eradicate or reduce the pathogen inoculum, breeding of resistant varieties, sampling and high-output detection methods of pathogens. Use and production of pathogen-free seed and propagation material, thermotherapy and meristem tip culture for obtaining virus-free plants.

Direct protection of plants from pathogens in organic agriculture: resistance of pathogens to chemicals, limitations and drawbacks of the application of specific biocontrol agents. Currently allowed agents (in E.U) of mineral origins: copper, sulfur, potassium bicarbonate, hydrated lime and others: activity, formulations, phytotoxicity and ecotoxicological profiles of these pesticides. Direct protection by biological control: microbial communities, biomass, activity and disease suppression in both phyllo-and rhizosphere, commercially registered biological products, suppressive soils and mycorrhizae. Viral parasites of bacteria (fagi) and fungi (mycoviruses), biological control of Endothia parasitica.

Natural compounds that can induce systemic resistance (SAR or ISR) in plants allowed in o.a.; the “recovery” phenomenon in phytoplasma diseases: recent knowledge and practical application.

2. Organic airborne, seedborne, soilborne and vectorborne diseases management (7 HRS.)

Organic management and airborne diseases: economic consequences of losses caused by airborne diseases, effects of macro- and micro-nutrients on basic functions of plant resistance, disease control strategies in organic systems: enhancement of soil microbial biomass and activity to encourage the breakdown of pathogen resting structures, interactions of weeds and surrounding vegetation with diseases, influence of epiphytes and endophytes on plant-pathogen interaction. Direct control of airborne diseases: currently used agents, properties and optimal use of plant protection products, decision support systems.

Organic management and soilborne diseases: soil quality and soil health in organic and conventional farming systems, soilborne diseases in organic versus conventional agriculture, factors associated with pathogen and disease suppression in o.a. Importance of free-living and beneficial nematodes in organic farming, plant damage caused by plant-parasitic nematodes, virus transmission by nematodes, nematode management by crop rotation, suppressive soils and biological control. Direct control of soilborne diseases by biofumigation, soil solarization and steam sterilization.

Organic management and seedborne and vectorborne diseases: production of healthy seed and propagation material as one of the key issues in the organic production cycle, economic importance of seedborne diseases, important seedborne diseases of cereals and vegetables. Correlation of disease control to the position of the pathogen on or in the seed; physical seed treatments and with agents of natural origins, effects of treatments on seed germination. Examples of vectorborne plant diseases, organic perspective on vectorborne diseases.

3. Examples of detection and identification of pathogens transmitted by propagation material (5 HRS.)

Biological diagnosis: woody and herbaceous plant indicators; ultrastructural studies by examination of sections of plant cells or of crude sap from virus-infected plants under the electron microscope; serological diagnosis: ELISA and its applications; molecular diagnosis: PCR and real time PCR.

MODULO 2 - SPECIFIC CROPS

ELEMENTS OF ORGANIC APPLE, APRICOT, GRAPE, PEACH AND VEGETABLE DISEASE MANAGEMENT (10 HRS.)

Organic apple, apricot and peach disease management: general crops characteristics and management, elements of important diseases (apple scab, powdery mildew, fire blight, fruit diseases, apple proliferation (pome fruits); taphrina, coryneum blight, powdery mildew, european cancker, brown rot, diseases caused by prokaryotes, plum pox virus (stone fruits). Control strategies: mechanical and physical control, direct control strategies with pesticides allowed in o.a. and biocontrol agents. Resistance-inducing products, the “recovery” phenomenon as a tool to riduce the economic pressure of phytoplasma diseases.

Organic grape disease management: general crops characteristics and management, elements of important diseases (downy mildew, powdery mildew, botrytis gray mold, black rot, root and wood rot diseases, grapevine yellows). Site selection, agronomic practices e.g. canopy management, mechanically breakdown of pathogens resting structures, use of resistant/tolerant cultivars (interspecific cvs.). Direct control strategies in humid and arid climates: use of copper and sulfur compounds in organic vineyards, recent restrictions of copper use in E.U., application of specific biocontrol agents.

Organic vegetable disease management: challenges of disease management for organic vegetables, management strategies e.g use of resistant cvs., site selection, cultural practices, planting stategies, use of healthy seed and propagation material. Some seedborne pathogens of vegetable crops and inoculum source, physical control methods, postplant applications of inorganic fungicides or biological control products, use of plants that actively suppress pathogens.

Organic greenhouse production: main crops, rotation and crop sequence, plant nutrition, irrigation and energy use. Control of diseases and weeds in organic greenhouses.

Organic food chain management: chain management methods (transportation, storage, processing, marketing), elements of post-harvest diseases of biotic origin and mycotoxin production. Human pathogens (Escherichia coli and Salmonella enterica) and pesticide residues in organic versus conventional products. Control of post-harvest diseases.

Readings/Bibliography

Power points and articles will be distributed during the course.

Elementi di patologia vegetale - G Belli (available in the library)

Plant pathology, fifth ed. - G. Agrios (av. in the library)

Plant disease and their management in organic agriculture - M. Finckh, A. van Bruggen, L. Tamm (av. in the library)

Teaching methods

During the course, the general issues related to an organic management to regulate diseases in several crops based on four cornerstones: biodiversity enhancement, good general crop management, use and production of pathogen-free seed and propagation material and of resistant cultivars, direct control of diseases, will be discussed. The economic consequences and the epidemiology of some diseases will be the basis of the organic management of specific crops.

The course will be complemented by practical laboratory trainings designed to simulate the diagnostic procedures, especially of pathogens transmitted by propagation material, in use in the most modern phyto-pathological research laboratories.

Assessment methods

The examination is oral and will contain a series of questions to ascertain the student’s theoretical knowledge of the issues presented in the course.

Teaching tools

Video projector, PCs, laboratories equipped with the most modern instruments for phyto-pathological diagnosis.

Office hours

See the website of Carlo Poggi Pollini