3.3 Flashcards
(13 cards)
In agriculture weeds cause a significant economic impact
1) cause a significant reduction in the productivity of the crop due to competition
2) release chemical inhibitors into soil which further reduces the crop
3) contaminate grain crops with their seeds and reduce the crops value
4) Act as hosts for crop pests and disease
Two types of weeds
Annual (yearly)
Perennial (ever present)
Annual
Rapid growth
Short life cycle
High seed output
Long term seed viability
Perennial
Underground storage organs
Already in habitat
Reproduce a sexuality
Harder to pull out
Vegetive reproduction
Plant diseases are cause by ______ and can either be
Pathogens
Bacteria
Fungi
Viruses
Systematic herbicides
Spreads through the vascular system of the plant including the underground storage organs and prevents regrowth
Systematic insecticides etc
Spreads through the vascular system of plants and kill plants
Three problems associated with pesticides
Toxicity to no target species
Persistence in the environment
Bioaccumulating or bio magnification in food chain producing resistance pests
Bioaccumulation
Buildup of a chemical in an organism
Biomagnifaction
An increase in the concentration of a chemical moving between tropic levels
Biological control agents
Natural predator
Parasite
Pathogen
Integrated pest management
Used a combination of biological control, cultural and chemical methods to control pests and diseases
Risks associated with bio control
The control organisms may become an Invasive species, parasite, prey on or be a pathogen of other species other than the pest
