a) Describe the life cycle of vine weevil using a labelled diagram. 6 marks
b) Describe TWO distinct symptoms of vine weevil damage. 4 marks
This question relates to the following part of the syllabus:
Outcome 3 Understand the problems posed by pests and methods by which they can be minimised.
3.1 Explain why pests need to be controlled.
State what is meant by the term ‘plant pest’. Describe the damage done by: - rabbits - cabbage white (large white) butterfly larvae - black bean aphid - peach potato aphid - two spotted spider mite - glasshouse whitefly - vine weevil - slugs - potato cyst eelworm
3.2 Describe the lifecycle of garden pests.
Describe in outline the life-cycles of:
- cabbage white (large white) butterfly
- black bean aphid
- glasshouse whitefly
- vine weevil
- potato cyst eelworm
Part a) is an example of a question requiring a diagram. Any diagrams should be large, clear and well labelled. The syllabus doesn’t specifically ask for a diagram, but you need to be able to describe the life cycle in outline. It is just another step to put this information down in diagram form with arrows between the different stages.
The examiners’ comments state that the best answers included:
· Virtually all vine weevils are female
· Female vine weevils lay approximately 500-600 eggs during spring and summer in the soil near the base of plants
· Eggs hatch into larvae between 8 days at 27oC and 56 days at 9oC
· Larvae are ‘C’ shaped, 1mm in length, creamy white with a chestnut brown head
· Larvae burrow into the soil to overwinter and then pupate when they are fully grown, 13mm
· Adults emerge as dull black beetles in April
· Vine weevil have a life cycle that is complete metamorphosis
Both parts of the question ask you to ‘describe’, so both need quite a bit of detail. For part b) the descriptions of vine weevil damage were suggested as:
‘’Notching’ of the leaf edges is carried out by adult weevils on evergreen foliage. Root damage is also carried out by larvae, which causes wilting, total collapse and often death of the plant especially in ornamental herbaceous plants’.