Crop protection 3.3 Flashcards
What is the impact of weeds, pests and diseases on crop plants?
Weeds compete with crop plants,
while other pests and diseases damage
crop plants, all of which reduce
productivity.
What are properties of annual weeds?
Properties of annual weeds — rapid
growth, short life cycle, high seed output
and long-term seed viability.
What are properties of perenial weeds?
Properties of perennial weeds with
competitive adaptations — storage organs
and vegetative reproduction.
What are the most common pests of crop plants?
Most of the pests of crop plants are
invertebrate animals such as insects,
nematode worms and molluscs.
What are plant diseases caused by?
What are they also carried by?
Plant diseases can be caused by fungi,
bacteria or viruses, which are often
carried by invertebrates.
What are the cultural methods used to control weeds, other pests and diseases?
Ploughing, weeding and crop rotation.
State the different types of pesticides and their uses?
Pesticides include herbicides to kill
weeds, fungicides to control fungal
diseases, insecticides to kill insect pests,
molluscicides to kill mollusc pests and
nematicides to kill nematode pests.
What are the advantages of selective herbicides?
Selective herbicides have a greater effect
on certain plant species (broad leaved
weeds).
What are the advantages of systemic herbicides?
Systemic herbicide spreads through
vascular system of plant and prevents
regrowth.
How do systemic insecticides, molluscicdes and nemacides work?
Systemic insecticides, molluscicides and
nematicides spread through the vascular
system of plants and kill pests feeding on
plants.
What are the problems with pesticides?
Problems with pesticides: toxicity to
non-target species, persistence in the
environment, bioaccumulation or
biomagnification in food chains, producing
resistant populations of pests
Which is more effective: the application fungicides or treating diseased crops?
Applications of fungicide based on
disease forecasts are more effective than
treating diseased crops.
What is bioaccumlation?
Bioaccumulation is a build-up of a
chemical in an organism.
What is biomagnification?
Biomagnification is an increase in the concentration of a
chemical moving between trophic levels.
What is the the control agent in biological control?
In biological control the control agent is a
natural predator, parasite or pathogen of
the pest.
