Unit 3 - Detection and identification of plant diseases

Question 1

State the name of a type of insect that attacks plants

Answer 1

Plants can also be attacked by insects such as aphids

Question 2

Complete the sentence
Plants can also be attacked by insects such as ______

Answer 2

Plants can also be attacked by insects such as aphids

Question 3

What do aphids do

Answer 3

Aphids extract nutrients such as sugars from the plant, stunting its growth

Question 4

State a feature found on an aphid - how does this help them do their job

Answer 4

Aphids have long sharp mouthpieces that penetrate into the phloem vessels of the plant so they that they can feed on the sugar-rich phloem sap

Question 5

State two things that insect pests can do to a plant

Answer 5

Insect pests may both destroy plants directly or act as vectors of disease

Question 6

State the number of aphids that can infest a plant, how is this a problem

Answer 6

They can infest a plant in large numbers and remove large quantities of the phloem sap. This can weaken the plant.
Also they deprive the plant cells of the products of photosynthesis. This can weaken and damage the plant.

Question 7

Aphids can act as ______ for the transfer of diseases

Answer 7

Aphids can act as vectors for the transfer of diseases

Question 8

What is a vector

Answer 8

A vector is an organism that transmits disease

Question 9

What can be done to control the infestation of aphids

Answer 9

Biological pest control (using ladybirds, a natural predator of the aphid) to feed on them

Using chemical pesticides are the best ways to control infestation with aphids

Question 10

How can plant diseases be detected (symptoms of plant diseases)

Answer 10

Plant diseases can be detected by:
* stunted growth
* spots on leaves
* areas of decay (rot)
* growths
* malformed stems or leaves
* discolouration
* the presence of pests

Question 11

State an example of a plant disease where stunted growth may be seen

Answer 11

Stunted growth

Rose Black Spot
Tobacco Mosaic Virus
Nitrate deficiency

Question 12

State an example of a plant disease where spots on leaves may be seen

Answer 12

Spots on leaves

Rose Black Spot

Question 13

State an example of a plant disease where areas of decay (rot) may be seen

Answer 13

Areas of decay (rot)

Rose black spot
Blights on potatoes

Question 14

State an example of a plant disease where the presence of visible pests may be seen

Answer 14

Presence of visible pests

Aphids
Caterpillars

Question 15

State an example of a plant disease where discolouration of the leaves may be seen

Answer 15

Discoloration

Chlorosis in magnesium deficiency
Mosaic patterns resulting from Tobacco Mosaic Virus

Question 16

State an example of a plant disease where growths may be seen

Answer 16

Growths

Crown galls caused by bacterial infections

Question 17

State an example of an instance where Malformed stems and leaves be seen

Answer 17

Aphids infestation
Caterpillars infestation

Question 18

What should be done if a plant disease cannot be treated

Answer 18

If a plant disease cannot be treated, remove the disease plants as quickly as possible to prevent the pathogens spreading through the garden, field of woodland

Question 19

How can plant diseases be identified

Answer 19

Diseases in the garden can be identified by comparing the symptoms in the living plant with disease descriptions in a gardening manual or online

When the symptoms of disease occur in crop plants or forest trees, experts may visit the field or woodland to observe the symptoms in their natural environment. They may then take samples of diseased materials to the laboratory to identify the pathogen using techniques that include DNA analysis.

Plant scientists, foresters, farmers and market gardeners can use testing kits that contain monoclonal antibodies to identify the presence of certain plant pathogens (for example, the fungal pathogen Botryis)

Question 20

State an example of non-communicable disease in plants

Answer 20

Non-communicable disease in plants

Mineral deficiency - they are not passed from one plant to another

Question 21

Complete the sentence
Plants need the correct amount of _____ to function properly

Answer 21

Plants need the correct amount of nutrients to function properly

Question 22

What could be a solution to if a plant is deficient in a certain type of mineral

Answer 22

If plants are deficient in a mineral these can be replaced by fertilisers added to the soil

These fertilisers are often shown as NPK ratios depending on the need of the plant that is being grown

Question 23

State the different types of mineral deficiencies found in plants

Answer 23

Nitrate deficiency
Magnesium deficiency
Potassium deficiency

Question 24

State the use of nitrates in plants

Answer 24

Nitrates - production of amino acids for proteins

Question 25

State the use of magnesium in plants

Answer 25

Magnesium - Synthesis of chlorophyll. Chlorophyll is needed for photosynthesis

Question 26

State the symptoms of nitrate deficiency

Answer 26

A lack of the nitrate ion causes stunted growth. This is because nitrate is needed for protein synthesis and therefore growth.

Question 27

State the symptoms of magnesium deficiency

Answer 27

Yellowing leaves (chlorosis) due to less chlorophyll and stunted growth

A lack of the magnesium ion causes chlorosis, because magnesium is required to make chlorophyll.

Question 28

What is chlorosis

Answer 28

Chlorosis is the yellowing seen on the leaves of plants when they cannot make chlorophyll due to a lack of magnesium ions.