3.3) Crop Protection Flashcards
1
Q
- What do weeds do and what are the properties of perennial and annual weeds?
A
-
Weeds compete with crop plants, while other pests and diseases damage crop plants,
➞ all of which reduce productivity
-
PERENNIAL WEEDS ♾️
➞ type of weeds that continue to grow every season
* storage organs (plant has food in all environmental conditions)
* vegetative reproduction (perenneial weeds can reproduce using other methods in additon to seeds - sexual reproduction) -
ANNUAL WEEDS 🗓️
➞ type of weed which completes its life cycle in one growing season or year
* rapid growth
* short life cycle
* high seed output
* long-term seed viability
2
Q
- What organisms can affect plant crops?
A
- Pests - Invertabrate animals:
➞ INSECTS (e.g. aphids)
➞ NEMATODES (e.g. parasitic roundworms)
➞ MOLLUSCS (e.g. slugs and snails)
3
Q
- How are plant diseases caught?
A
- Plant diseases can be caused by:
➞ FUNGI 🍄
➞ BACTERIA 🧫
➞ VIRUSES 🦠
4
Q
- What are some cultural control methods?
A
-
PLOUGHING
➞ buries perennial weeds so they die and decompose -
WEEDING
➞ weeds removed early in the life of the crop allows the crop to become stronger -
CROP ROTATION
➞ a series of different crops are grown on the same piece of land over time (the current crop will not have the same pests as the next crop)
5
Q
- What are some chemical control methods?
A
- Pesticides, which include:
➞ HERBICIDES (kill weeds) 🌿
➞ FUNGICIDES (control fungal diseases) 🍄
➞ INSECTICIDES (kill insect pests) 🪲
➞ MOLLUSCICIDES (kill mollusc pests) 🐌
➞ NEMATICIDES (kill nematode pests) 🪱
6
Q
- What are the advantages of selective or systemic pesticides?
A
-
SELECTIVE:
➞ herbicides have a greater effect on certain plant species (broad leaved weeds)
↳ Crop plants absorb little of the chemical.
➜ Selective herbicides are biodegradable and do not cause harm to the soil. -
SYSTEMIC:
➞ herbicides spreads through the vascular system of plants and prevents regrowth
↳ other systemic pesticides (insecticides, molluscicides and nematicides) spread through the vascular system of plants and kill pests feeding on plants.
7
Q
- Describe problems with pesticides in terms of bioaccumulation and biomagnification.
A
- Some pesticides used in crop production have found to be toxic to non-target species (e.g. animals)
- There are examples of chemicals (such as DDT) that persist in the environment and accumulate over time.
➞ This is called bioaccumulation and involves the build up of chemicals in an organism. - An increase in the concentration of a chemical (such as DDT) moving between the trophic levels of a food chain is known as biomagnification.
➞ This may lead to poisoning if animals further along the food chain, or resistant pest populations.
8
Q
- What is a biological control and can you explain the risks with biological control?
A
- ‘Biological control’
➞ reduces the pest population by using a natural parasite, predator or pathogen. - The risks with a biological control
➞ include the control organism becoming an invasive species, or it becoming a parasite, predator or pathogen of another species. - Invasive species can spread rapidly and/or eliminate native species
9
Q
- Describe ‘integrated pest managment’
A
- ‘Integrated pest management’
➞ is the combination of cultural, chemical and biological control.