Sustainability and Interdependence - Crop Protection

Question 1

monoculture

Answer 1

single crop species cultivated over a large area to improve efficiency of farming

Question 2

weeds

Answer 2

unwanted plant in a monoculture which competes with the crop plant for resources

Question 3

annual

weeds

Answer 3

• colonise before the growth of the crop
• rapid growth rate
• short life cycle
• produce large number of seeds which are viable for long periods of time

Question 4

perennial

weeds

Answer 4

• live for more than two years and have adaptations which allow them to outcompete the crop plant
• possess storage organs which allow growth even when conditions are not ideal
• ability to use vegatative (asexual) reproduction

Question 5

pests

Answer 5

organism which damages the crop plant and reduces plant productivity

most are invertebrates: insects, molluscs, nematode worms

Question 6

diseases

pathogens

Answer 6

• caused by fungi, bacteria, or viruses which damage the crop plant and reduces plant productivity
• often carried by invertebrates but can be transferred through soil and air

Question 7

control by cultural methods

definition

Answer 7

non-chemical methods of preventing problematic organisms from establishing and damaging the crop plant(s)

Question 8

control by cultural methods

name the methods

Answer 8

• ploughing
• removal of weeds
• crop rotation and cover crops
• removal of alternative hosts
• destruction of crop residue

Question 9

ploughing

control by cultural methods

Answer 9

top layer of soil is turned over to bury perrenial weeds which die and decompose

Question 10

removal of weeds

control by cultural methods

Answer 10

removal of weeds early in the life of the crops to reduce competition and give the crop plant a headstart

Question 11

crop rotation and cover crops

control by cultural methods

Answer 11

growing very different crops in successive years in a field prevents the build up of pathogens which could cause issues if the same crop was grown the year after

Question 12

removal of alternative hosts

control by cultural methods

Answer 12

weeds are removed at the edge of fileds as they may provide a habitat for pests or vectors of disease

Question 13

destruction of crop residue

control by cultural methods

Answer 13

stubble can contain fungal pathogens so stubble is removed or ploughed into the ground to prevent issues from arising

Question 14

control by chemical means

Answer 14

chemicals can be used to control pests e.g. herbicides, fungicides, insecticides, molluscicides, and nematicides

Question 15

selective

herbicide

Answer 15

stimulates growth until broad leaved plant weeds exhaust food reserves and die

e.g. preen

Question 16

contact

herbicide

Answer 16

non-selective as it kills anything it touches but its effects are short lived as perrenials with storage organs are able to regrow

Question 17

systemic

herbicide

Answer 17

absorbed by weed and spreads through the vascular system to destroy the whole plant and prevent regrowth

Question 18

disease forecast

Answer 18

predicting when outbreaks of pathogens may occur and applying fungacides during these conditions to prevent an outbreak from occuring

Question 19

problems with agrochemicals

Answer 19

• toxicity to non-target species
• persistence in the environment
• bioaccumulation
• biomagnification
• production of resistant pest species

Question 20

toxicity to non-target species

problems with agrochemicals

Answer 20

pesticides can be poisonous to not just the pest but a broader range of animals including humans

e.g. dieldrin

Question 21

persistance in the environment

problems with agrochemicals

Answer 21

some chemical do not biodegrade and remain in the environment for long periods of time

e.g. DDT

Question 22

bioaccumulation

problems with agrochemicals

Answer 22

• if an organism absorbs a chemical from the environment at a faster rate than is is lost, bioaccumulation occurs
• over time the chemical can become toxic

Question 23

biomagnification

problems with agrochemicals

Answer 23

chemicals can be magnified along food chains as the concentration of the chemical increases from one trophic level to the next

Question 24

production of resistant pest population

problems with agrochemicals

Answer 24

• continued pesticide use exerts a selection pressure on the pest population
• few individuals are already resistant due to a random mutation so have a selective advantage
• resistant individuals are selected for and survive to breed the next generation
• over generations the resistant individuals increase in number to produce a pest resistant population

Question 25

biological control

definition

Answer 25

reduction in a pest population by the deliberate introduction of one of its natural predator, parasite, or pathogen

Question 26

biological control

problems

Answer 26

• may become a pest
• be invasive and reduce biodiversity
• could introduce parasites or pathogens
• my be a parasite to other organisms
• may distrupt food chains and webs

Question 27

integrated pest management

IPM

Answer 27

combines cultural, chemical, and biological controls in a combinational approach to manage pest populations whilst reducing the impacts of management strategies on the environment