Plant disease
Relationship between two organisms
Host-Parasite Interaction
Key points about host-parasite interactions
i-Parasite benefits, host is harmed
ii- Coevolution
iii- Immune Response
iv- Life cycle complexity
Parasites can cause wide range of secondary effects in human, animals, and plants. These effects can cause from mild to severe.
Diseases as a Secondary Effect of Parasitism
Secondary effect for humans
i-Malnutrition
ii- Anemia
iii- Organ Damage
Secondary effects for Animals
Reduced Growth and Yield, Increased Susceptibility to Disease, Structural Damage, Reduced Growth and Productivity, and Behavioral Changes
Measurable symptoms caused by harmful agent or any observation from the normal crop, injury may lead to damage.
Crop Injury
Any reduction in quantity/quality of yield decrease in the quantity or quality of a product damage may lead to loss
Crop Damage
The reduction in financial return per unit due to harmful agents
Crop Loss
Losses in quality and quantity of product and losses in production
Direct Loss
Losses occuring in the absence of control
Potential Loss
Losses in the yield, quality and income as a direct consequences of plant diseases before or after harvest
Primary Loss
Losses due to contamination of planting materials; soil borne diseases
Secondary Loss
Losses in the economic and social sphere ascribed to plant disease.
Actual Loss
Losses in the social sphere, not Withstanding more or less successful disease control, economic and social effects of plant diseases
Indirect Loss
Refers to scientifically based activity designated to slow down pathogen attack and or reduce the losses of crop yield at various degree of infection
Plant Disease Control
crop losses 2 kinds of economic effects
Increase in the cost of production
Reduction in the quantity and quality of plant products
PDM Principles whose efforts are directed chiefly towards the pathogen (Causal Agent)
Exclusion
Eradication
Prevent pathogens by whatever means and methods from entering and establishing in areas or regions not yet invaded.
Exclusion
Critical Examination of all suscepts or other bearers that might harbor suspected pathogens at the port of entry, customs offices along international boundaries, at receiving points or even at the farm or garden of the grower
Holding possible harborers for a definite period under survellance to determine whether suspected pathoges by their development will reveal their presence
Interception
Disinfection and disinfestations of all possible bearers or harborers at the point of entry or origin to insure destruction or removal of the pathogens.
Elimination
Commonly attempted through quarantine
Prohibiting the importation of possible of pathogens from infested areas by expert investigation of possible danger from threatening pathogen and then drafting and administering quarantine laws and regulations
Prohibition
Removal, elimination, or destruction of a pathogen from an area or individual plant in which is already established
Eradication
Effective disposal of disease plants, parts of plants, or infested plant debris
Removal
Indirect measures by which the pathogen is rendered innocuois on account of inability to perpetuate successfuly or propagate itself in the area
Elimination
Direct measures in which the pathogen is killed in situ, either on or in the suscept or in the environment, usuallt effected through disinfection by chemical agent or heat
Destruction
PDM principle whose efforts ate directed chiefly towards the suscept (plant crop)
Protection
Immunization
Interposition of some effective barrier between the suscept and pathogen which is generally present and in a position under favorable condition to bring about infection
Protection
Thinning seedlings, Proper irrigation and drainage, Erection of windbreaks, control of temperature, changing of soil pH
Manipulation of factors conditioning infection (non-chemical)
Shielding of plants from infection by spraying or dusting plants and plant parts with water-insoluble chemical substances or compounds which eventually become soluble and toxic in the presence of active inoculums of the pathogens
Application of protectants (chemical)
The reduction of disease below ETLs by the use of integrated control measures. Managing resources such as manpower, financial, available control measures to keep pathogens below levels that can cause yield losses and economic losses.
Disease Management in Practice
Measure through physiological processes, structural nature, or habits of individual plants or plant population are temporarily or permanently changed
Immunization
selection of klendusic, tolerant, or immune individuals with plant population
Selection
Crossing susceptible but desirable individuals with less klendusic, resistant, tolerant immune
Hybridization
Application of fertilizer to effect temporary or non-hositable freedom disease
Nutrition
Introduction of chemical substances toxic to the pathogen into plant tissues
Medication
Introduction of vaccines, serums, into plants
Vaccination
Implies finality dominated by human decisions; recurrence of the disease being controlled indicated that the disease is not controlled
Disease Control
Conveys the concept of continuous process rather than an event accomplished with the application/implementation of an extrinsic factor. It implies diseases are inherent components of the agro ecosystem. Management is based on the principle of maintaining los below an economic injury level. it suggests the continuous need for adjustments in the system of control
Disease Management
Is borrowed concept from IPM. It was developed to optimize productivity per unit area including the optimization of resources because of intensive agricultural production and the inadequacy of control strategies in many diseases.
Integrated Pest Management
one of the principles of Disease Management that diseases of obvious economic importance in the agro ecosystem should be first tackled identification of the problem is the first step in developing a disease management scheme.
Identify the disease to be managed
one of the principles of disease management is that the management unit is the agro ecosystem where the crop is being grown. It includes the complex interactions of all living organisms including the social structure of the community in the locality, including the effects of the strategies to be implemented on the environment
Define the Management unit
One of the Principles of Disease Management that the strategies must be able to control the disease by lowering the incidence of the disease (i.e. reducing the amount of inoculums). it should also reduce the rate of disease development
Develop the management strategy