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Causes and effects of disease in agricultural production - Coggle Diagram
Causes and effects of disease in agricultural production
Plant disease
Case study: Panama disease of bananas
Panama Tropical Race 4 disease
Caused by highly contaigous fungi
Fusarium oxysporum
Causes
Yellowing of leaves
Wilting of leaves
Splitting of stems
Causes of infectious disease in plants
Attacked by pathogens
Fungi
Insects and mites
Bacteria
Nematodes
Viruses
Phytoplasmas
Animal disease
Factors contributing
Increased mobility of human populations
Travellers + imported livestock and plants can carry infectious disease into Australia
Both cellular and non-cellular pathogens create reservoir in:
Food
Soil
Seeds
Changing patterns of land use
Deforestation
Loss of habitat
Climate change
Antimicrobial resistance
Case study: Footrot in sheep
Infectious disease
Found in hooves of:
goats
cattle
sheep
Caused by pathogenic bacterium
Dichelobacter nodosus
Factors affecting
Pathogen factors
Dichelobacter nodosus
must be present for footrot to occur
Environmental factors
The bacterium will only survive in soil outside the host for maximum 4 days
Pastures that are long, dense and wet aid pathogen survival + tranfser
Temperature - warm weather favours bacterial growth
Host factors
Dry feet with intact tissues are no infected
Reservoirs of bacteria may form in individual animals feet for years
Some dermatitis between the toes must already be present for bacteria to invade and establish an infection
Overgrown hooves provide a suitable environment for the bacteria
Infectious diseases in Australian agriculture
Two main disease types:
Endemic
consistently present within a country or region eg; footrot in sheep
Exotic
Introduced diseases eg; influenza
Factors affecting infectious disease
Host
succeptible to disease
access to pathogen
concurrent disease
poor nutrition leading to weakened immune response
drought
Pathogen
availability
ability to transfer between hosts
adhesion and invasion of host tissues
Environmental
overcrowding
lack of hygeine
