Crop protection

Question 1

Describe the effects of weeds, pests and diseases on crop plants?

Answer 1

• Weeds COMPETE with crop plants, while pests and diseases DAMAGE crop plants all of which reduce productivity.

Question 2

What are the properties of annual weeds?

Answer 2

• rapid growth
• short life cycle
• high speed output
• long term seed viability

Question 3

What are the properties of perennial weeds with competitive adaptations?

Answer 3

• storage organs
• vegetative production

Question 4

State the pests of crop plants?

Answer 4

most are invertebrate animals such as insects, nematode worms and molluscs.

Question 5

What is the cause of diseases with these plants?

Answer 5

Diseases in the plants can be caused by fungi, bacteria or viruses, which are often carried by invertebrates.

Question 6

How do we control the pests, diseases and weeds?

Answer 6

Ploughing, weeding and crop rotation.

Question 7

Describe the pesticides?

Answer 7

• Pesticides include herbicides to kill weeds.
• Fungicides to control fungal diseases.
• insecticides to kill insect pests.
• molluscicides to kill mollusc pests.
• nematicides to kill nematode pests.

Question 8

Describe systemic and selective herbicides.

Answer 8

• selective herbicides have a greater effect on certain plants species (broad leaved weeds).
• systematic herbicides spread through the vascular system of plants and prevent regrowth.

Question 9

Describe systemic insecticides, molluscicides and nematicides?

Answer 9

They spread through the vascular system of the plant and kill the insects feeding on the plant.

Question 10

State the problems with using pesticides?

Answer 10

• toxicity to non-target species.
• persistence in the environment.
• bioaccumulation or biomagnification in food chains.
• producing resistant populations of pests.

Question 11

Describe the application of fungicides?

Answer 11

The application of fungicides based on disease forecasts are more effective than treating diseases crops.

Question 12

What is bioaccumulation and biomagnification?

Answer 12

• Bioaccumulation is the build-up of a chemical within an organism.
• Biomagnification is an increase in the concentration of a chemical moving between trophic levels.

Question 13

Describe biological control of pests, weeds and diseases?

Answer 13

In biological control the control agent is a natural predator, for example control of glasshouse whitefly with the parasite wasp Encarsia, red spider mite with the predator mite.

Question 14

Describe integrated pest management?

Answer 14

Integrated pest management is a combination of chemical, biological and cultural control.

Question 15

Describe the risk of biological control?

Answer 15

The control organism may become an invasive species, parasite, prey on or be a pathogen of other species