Higher Biology - Unit 3 - Part 3 - Crop Protection Flashcards
Weeds compete with crop plants, while pests and diseases damage them all, reducing……
productivity
Properties of annual weeds include ……..
- rapid growth,
- short life cycle,
- high seed output,
- long-term seed viability.
Properties of perennial weeds include …
storage organs and vegetative reproduction.
Most of the pests of crop plants are ………
invertebrate animals such as insects, nematode worms and molluscs.
Plant diseases can be caused by …..
fungi, bacteria or viruses, which are often carried by invertebrates.
Protective applications of fungicide based on ______________ are often more effective than treating a diseased crop.
disease forecasts
selective plant protection chemicals will only affect
one type of plant
a systemic herbicide has the advantage that….
it will reach all parts of the plant, even a stubborn root that might otherwise remain in the ground allowing the root to regrow
On a farm, weeds, pests and diseases can be controlled by CULTURAL METHODS such as
- ploughing,
- weeding
- cover crop
- crop rotation
The problems with plant protection chemicals are that they can …
- persist in the environment
- become magnified in food chains,
- can be toxic to animals and resistant populations can be produced.
In biological control the control agent is a natural __________ or parasite of the pest.
predator
Control of glasshouse whitefly with the parasitic
wasp Encarsia is an example of ….
biological control
Integrated pest management combines…..
- chemical
- biological and
- cultural control.
Integrated pest management (IPM) emphasizes the growth of a healthy ______ with the least possible disruption to ecosystems and encourages natural pest control mechanisms
crop
Biological controls are useful as they …..
avoid harmful chemicals from pesticides getting into the food chain (or persisting in the environment)
