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Biocontrol and IPM. Reading Assignment: Chapters 34 and 35. Biocontrol. Control of plant pathogens with other microbes A biological control agent is known as an antagonist Antagonism is general name for mechanisms of biological control. Antagonism. Antibiosis. Competition. Parasitism.
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Biocontrol • Control of plant pathogens with other microbes • A biological control agent is known as an antagonist • Antagonism is general name for mechanisms of biological control
IPM • IPM is the management of diseases by optimizing control strategies to prevent diseases from causing economic losses • Purpose of disease control: prevent disease damage from exceeding level where profit or required yield is significantly diminished
How do we prevent profit losses? • Reduce (delay) disease at the beginning of the season (Xo) • Decrease rate of disease development (r)
When do we act? • Economic injurylevel: “damage threshold” – the level Xt at which disease begins to be adversely affect yield and/or quality • Level of injury may vary from one region or farmer to the next region or farmer
When do we act? • Action threshold – “Economic threshold” – pathogen density at which control measures should be taken to prevent pathogen from reaching the economic injury level • Farmer must act to reduce r so that disease dose not reach EIL before harvest
Economics • Growers can be expected to increase resources for crop protection until the amount of money expended = additional crop income
Factors that effect economic thresholds • Producers attitude • Crop income – disease incidence relationship • Control costs – pathogen population relationships
Economics • Tolerance level: amount of disease where crop income falls as disease levels increase • Income losses can result from decreased yields and/or decreased quality • How much disease can be tolerated on a poinsettia or a golf green?
Value of yield Probable cost of disease control Cost of several alternative control measures Efficiencies of controls in reducing disease Expected impact of a given pathogen intensity on quality and quality of yield What the grower should know
What can influence farmer’s decisions? • Level of credit or affluence • Undetected crop loss • Aversion to risk