Pests and Agriculture Flashcards
What are categories of pests?
fungi bacteria insects animals/birds weeds viruses prions
By what mechanisms can fungi influence productivity?
decrease photosynthesis by covering the leaves (leaf melt) and reducing the leaf area
decrease nutrient and water uptake by damaging/reducing roots or by physical barriers
reduce output or quality by damaging the fruit
By what mechanisms can bacteria influence productivity?
decrease photosynthesis by covering the leaves (leaf melt) and reducing the leaf area
decrease nutrient and water uptake by damaging/reducing roots or by physical barriers
reduce output or quality by damaging the fruit
By what mechanisms can insects influence productivity?
decrease photosynthesis - eat leaves, knock over plants (stalk damage)
decrease quality - eat fruit and other parts
vector for disease
insect to insect interference
How can animals or birds influence productivity?
eat plants pull up seeds damage infrastructure trample plants disease transmission - weaken plants, especially in animals
How can weeds influence productivity?
compete for resources - nutrients, sunlight, water
harvest difficulties
provide habitat for other pests
parasitic weeds - grow directly on plants
What is a key difference between annual and perennial weeds?
annuals want to seed quickly before the crop - get to the resources first
Which pest type has highest potential losses?
weeds, but we are most effective at controlling them
What are abiotic vs. biotic crop losses?
abiotic - solar irradiation, water, temp, nutrients
biotic - weeds, animals, pathogens
attainable yield
site specific maximum production per acre within the abiotic limits
potential loss
level of damage in absence of any pest control
actual loss
level of damage incurred despite pest management
definition of loss
w%=[(m-y)/m] x 100
w = loss in yield
m = max. yield
y = yield in presence of pests
How can losses from pests vary by region?
places with higher yields have more incentive to control pests
