R2103 3 PESTS

Question 1

Plant pest definition

Answer 1

A mammal, bird, insect, mollusc or nematode that is damaging to plants

Question 2

Describe the damage: rabbit

Answer 2

BITES

Grazing, ring barking. Commonly eats lettuces, carrots, annual bedding plants.

Question 3

Describe the damage: Cabbage white butterfly larvae

Answer 3

BITES

Usually eats plants in brassicaceae family. Defoliates the plants, may result in skeletonised leaves with just the main veins showing

Question 4

Describe the damage: Black bean aphid

Answer 4

PIERCING

Stunts growth. Curled and distorted foliage. Can cause sooty mould and carry viruses as secondary damage

Question 5

Describe the damage: Peach potato aphid

Answer 5

PIERCING

Sap sucking, Yellowing, mottled leaves, distorted young growth. Can cause sooty mould and carry viruses as secondary damage

Question 6

Describe the damage: Two spotted spider mite

Answer 6

PIERCING

Webbing on leaves, leaf mottling, foliage and flower detoriation, loss of plant vigour

Question 7

Describe the damage: Glasshouse whitefly

Answer 7

PIERCING

Weakened growth, reduced flowering and fruiting potential. Sticky honeydew on the leaves, can cause sooty mould

Question 8

Describe the damage: Vine weevil

Answer 8

BITES

Notched leave margings
Larvae eat roots

Question 9

Describe the damage: Slugs

Answer 9

RASPING

Eat mostly leafy and young growth. Make irregular holes in plant tissue. Can completely decimate young seedlings

Question 10

Describe the damage: Potato cyst eelworm

Answer 10

PIERCING

Damaged root system of patotoes and tomatoes cause lack of vigour and poor yield. Also causes cyst on roots

Question 11

Life cycle: Cabbage white butterfly

Answer 11

• April- May adults emerge from overwintering pupa, mate and lay eggs on the underside of the leaves.
• Withing fortnight larvae emerge. Usually around 2.5cm in lengh yellow and green in colour with black markings
• June pupa stage occours in crevices of woody stems
• July second generation or adults emerge and lay eggs. In fortnight, the larvae appear which is usually more damaging than the first generation.
• The second generation pupa overwinters

Question 12

Life cycle: Black bean aphid

Answer 12

• Overwinters in an eggs state usually on Euonymus europaeus
• March/April female nymphs emerge and at maturity fly to summer host plants such as beans and beets
• Females lay as many as 5 females per day which are themselves then ready to produce more young aphids within 14 days
• In Autumn nymps start producing winged males and females which fly to lay eggs on winter host plants where they overwinter

Question 13

Life cycle: Slugs

Answer 13

• Slugs are hermaphrodites
• Spring/Summer - mating season. Lay clusters of up to 50 eggs in rotting vegetation.
• Take around a year to mature
• Overwinters as young slugs or eggs
• More active in moist conditions

Question 14

Life cycle: Potato cyst eelworm

Answer 14

• Spring: the eggs hatch which are stimulated by chemicals present in neightbouring potatotes
• The larvae invade the potato roots, disturbing vascular systems
• Summer: adult females start to swell, the body develops into a cyst and protrudes outside the root. Male fertilises the cyst and dies
• Autumn/winter fertilised cyst detaches from the plant root, back into the soil when plant is harvested.
• Cyst can persist in the soil for 10 years until the viable host is detected

Question 15

Methods of breathing used by insect pests

Answer 15

Insects breathe through spiracles. Fatty acid chemicals block the spiracles

Question 16

How can chemicals enter the insects

Answer 16

• Through spiracles
• Waxy exoskeleton
• Digestive system

Question 17

How the pests can be controlled x2: Rabbit

Answer 17

Physical - plastic guards

Chemical - Aluminum ammonium sulphate sprayed aroung the plants

Question 18

How the pests can be controlled x2: Cabbage white butterfly larvae

Answer 18

Physical - very fine netting to prevent adults laying eggs

Biological - encouraging birds such as blue tits who eat them

Question 19

How the pests can be controlled x2: Black bean aphid

Answer 19

Biological - attached by ladybirds, lacewings, hoverfly larvae

Physical - hosing them off, squashing them by hand

Question 20

How the pests can be controlled x2: Peach potato aphid

Answer 20

Biological - lady birds, lacewings, hoverfly larvae etc

Chemical - fatty acids

Question 21

How the pests can be controlled x2: Two-spotted spider mite

Answer 21

Chemical - fatty acids

Physical - removing badly infected plants

Question 22

How the pests can be controlled x2: Glasshouse whitefly

Answer 22

Chemical - fatty acids

Cultural - removing alternative hosts

Question 23

How the pests can be controlled x2: Vine weevil

Answer 23

Physical - hand picking when active at night

Biological - nematodes

Question 24

How the pests can be controlled x2: Slugs

Answer 24

Physical - hand picking them off at night

Chemical - Ferric phosphate

Question 25

How the pests can be controlled x2: Potato cyst eelworm

Answer 25

No chemical control available

Cultural - growing early potatoes which allow harvesting before the cyst forms

long crop rotation

growing resistant varieties

Question 26

Life cycle: Glasshouse whitely

Answer 26

• Fertilised female lays about 200 eggs in a circular pattern on the undersurface of the leaf
• The eggs produce nymphs which develop into scales (pupa) from which the male and female adults emerge
• Females are ready to lay legs within 3 days
• The whole cycle can take 23-32 days depending the season. The warmer the weather, the faster
• Active all year due to being mainly houseplant and glasshouse pest

Question 27

Life cycle: Vine weevil

Answer 27

• The adult is 9mm long, black in colour. Incapable of flight. No males known
• The female lays eggs (mainly in august and september) in soil or compost next to roots of preferred speciels. Over of period of 2 years she may lay 1000 eggs as she visits many plants
• The larvae are white and legless with chestnut brown head
• They pupate in December in soil