Weeds, pests and diseases

Question 1

Monoculture

Answer 1

Often present in agriculture it is a single crop species (sometimes even genetically identical), cultivated over a large area.
A monoculture helps to
improve efficiency.

Question 2

Problems with monoculture

Answer 2

Monoculture provides ideal growing conditions for pests – weeds, pests and pathogens.
The plentiful food
supply enables the problem organism’s population to increase.
Leading to a consequent reduction of yield.

Question 3

Weeds

Answer 3

Weeds are plants which grow where they are not wanted and compete with crop plants for resources .

Question 4

Effects of weeds

Answer 4

Reduction in crop productivity due to competition;
• Release chemicals which inhibit growth of the crop;
• Contaminate grain crops with their seeds;
• Act as hosts for diseases and crop pests.

Question 5

Annual crop weeds competitive adaptations

Answer 5

➢Have a rapid growth rate;
➢Produce flowers quickly and have a short lifecycle;
➢Produce large numbers of seeds;
➢Have seeds which are viable for long periods of time.

Question 6

Annual weeds lifespan

Answer 6

Year long

Question 7

Perennial weeds lifespan

Answer 7

Live for more than 2 years

Question 8

Perennial weeds competitive adaptations

Answer 8

➢possession of storage
organs to provide food if growing conditions aren’t ideal;
➢ability to use vegetative
reproduction with
structures such as runners.

Question 9

Pest

Answer 9

A pest is an organism which damages crop plants, this could be the whole plant or a part of the plant.
All pests reduce plant productivity.

Question 10

Invertebrate pests

Answer 10

Animals such as insects, molluscs and nematode worms.

Question 11

Plant diseases caused by

Answer 11

Plant diseases can be caused by fungi,
bacteria or viruses – these are often carried
by invertebrates but can also be carried in soil or air.
Diseases also damage crops and reduce productivity.