Riassunti VERIFICATO
Patologia viticola
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- Plant Protection Fundamentals:
- Plant pathology is crucial for protecting against diseases, insects, and other parasitic organisms.
- Integrated plant protection utilizes scientific, appropriate, and expert-driven measures, covering pest management, irrigation, nutrition, and control methods with minimal environmental impact.
- It's a multidisciplinary field involving pathologists, agronomists, chemists, geneticists, and IT experts.
- International organizations like IPPC (International Plant Protection Convention) and CBD (Convention on Biological Diversity) establish frameworks for managing plant pests and invasive exotic species, aiming to harmonize control measures and conserve biodiversity.
- Phytosanitary Barriers & Regulations:
- Phytosanitary barriers limit international trade to protect domestic agriculture, based on scientific justification (Pest Risk Analysis-PRA).
- The WTO SPS Agreement ensures trade measures are not arbitrary, and IPPC is the designated organization for plant health.
- Regional Plant Protection Organizations (RPPOs) and EPPO (European Plant Protection Organization) coordinate efforts, promote standards, and manage quarantine pests.
- EFSA (European Food Safety Authority) provides independent scientific advice on food chain risks.
- Certification systems (phytosanitary certificates, plant passports) ensure high-quality, pest-free propagation material. Management strategies include defining "indemne zones" (pest-free), "contaminated areas," "settlement zones," and "buffer zones."
- Viruses and Viroids:
- Viruses are obligate intracellular parasites, composed of nucleic acid (RNA/DNA) in a protein coat (capsid), replicating only inside host cells. They exhibit various symmetries (helical, icosahedral) and transmission methods.
- The infection cycle involves passive penetration, decapsidation, replication, assembly, translocation (cell-to-cell via plasmodesmata, systemic via phloem), and transmission to new hosts.
- Symptoms are macroscopic effects but often non-specific, influenced by mixed infections and environmental conditions.
- Viroids are smaller circular RNA pathogens, lacking a protein coat and using host enzymes for replication. They are highly stable and primarily infect higher plants, causing symptoms like dwarfism, decoloration, and cracks. They move via plasmodesmata and phloem.
- Diagnosis for both relies on molecular methods (PCR, sequencing) and biological indicators, as serology is not applicable for viroids.
- Grapevine Viroses:
- Vines are affected by numerous viruses, viroids, phytoplasmas, and bacteria.
- Syndromes include infectious degeneration (GFLV, ArMV) transmitted by nematodes, leafroll (GLRaVs) transmitted by mealybugs, rugose wood complex (Vitiviruses) also transmitted by mealybugs, and infectious mottling (GFkV).
- These diseases compromise vine health, reduce vineyard lifespan, decrease stress resistance, and negatively impact yield quality/quantity.
- Control strategies focus on prevention: use of healthy propagation material, early diagnosis, clone sanitation (thermotherapy, meristem culture), vector control, and removal of infected plants.
- Graft incompatibility and Grapevine Pinot Gris Virus (GPGV) are specific open issues with ongoing research and diagnostic protocol development.
- Phytoplasmas and Grape Yellows:
- Phytoplasmas are systemic bacteria developing in phloem, transmitted by insect vectors like Scaphoideus titanus (for Flavescence dorée - FD) and Hyalesthes obsoletus (for Bois noir - LN).
- Symptoms of grapevine yellows include chlorotic vegetation, shortened internodes, poor lignification, and shriveled clusters. Diagnosis is primarily molecular (PCR).
- Control measures involve managing vectors, removing infected plants, and agronomic practices; direct control with oxytetracycline injections is prohibited in the EU.
- Agrochemicals and Toxicology:
- Agrochemical use is strictly regulated by EU directives (e.g., Reg. 1107/2009, 396/2005, 128/2009) to ensure safety for humans and the environment.
- Risk assessment considers hazard (intrinsic toxicity) and exposure (duration/intensity of contact), with toxicity evaluated via LD50, NOAEL, ARfD, and ADI.
- Environmental risks include drift, volatility, runoff, and leaching, influenced by physicochemical properties, climate, and soil.
- Fungicides are classified by origin (natural, synthetic), action (cover, penetrating, systemic), and target. Their efficacy depends on fungitoxicity and availability at the target site.
- Pathogen resistance to fungicides is a major concern, influenced by genetic mutations, action mechanism, and application practices.
- Pest Management Strategies:
- Defense strategies evolved from calendar-based treatments to guided control (threshold-based) and integrated pest management (IPM), which optimizes all available techniques (agronomic, physical, biological, chemical).
- IPM prioritizes ecological methods and aims for quality production while respecting the environment.
- Biological control utilizes natural antagonists to keep pest populations within acceptable limits, promoting ecosystem balance.
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