Past paper September 2020

Question 1

Name a glasshouse pest

Answer 1

glasshouse whitefly

two spotted spider mite

Question 2

Name an outdoor pest

Answer 2

slug
cabbage white butterfly larvae
black bean aphid

Question 3

methods of control for glasshouse whitefly minimising use of pesticides are:

Answer 3

introduction of tiny parasitic wasp Encarsia formosa before plants become heavily infected.

Question 4

name a parasitic wasp

Answer 4

Encarsia formosa

Question 5

how does Encarsia formosa control glasshouse whitefly?

Answer 5

they prey on whitefly scale nymphs

Question 6

how can glasshouse whitefly be controlled other that with parasitic wasps?

Answer 6

good hygiene.

weed control in/around glass house to remove host plants

Question 7

How can slugs be controlled in a natural way? (predator)

Answer 7

Microscopic nematode
(Phasmarhabditis hermaphrodita)

hedgehogs
frogs

Question 8

How do you apply nematodes to an area?

Answer 8

you can water them onto the soil from spring to early autumn.
Soil temp must be 5-20 degrees C

Question 9

How does a nematode kill a slug?

Answer 9

It enters a slug’s body, and infects it with bacteria with causes a fatal disease.

Question 10

apart from nematodes, how else can you kill a slug in a natural way?
-think about predators

Answer 10

attract hedgehogs into garden-they like log piles.

ponds with sloping sides- to attract frogs.

Question 11

describe the lifecycle of a glasshouse whitefly

revise a diagram too

Answer 11

lay greyish-whire, cylindrical eggs singly or in circles on underside of leaf

Each female can lay more than 200 eggs

Males are rare-reproduction takes place without need for fertilisation

Eggs hatch into small crawlers (scale-like nymphs) which crawl around for a bit before they start to feed and become immobile

Nymphs are flat,oval shaped, whitish-green and 1mm long

final nymph stage is a PUPA and the adult whitefly emerges through a slit in the dorsal surface

Question 12

How does temperature affect the lifecycle of the glasshouse whitefly?

Answer 12

The length of the lifecycle varies according to temps.

At 10’C the life cycle takes several months.
at 21’C it takes three weeks.

Question 13

Describe how glasshouse whitefly feed including the damage they cause

Answer 13

feed by sucking sap of plants using a stylet.

That reduces vigour of plant.

Whitefly excretes a sticky, sugary substance called HONEYDEW onto upperside of the leaves enabling growth of a black sooty mould which reduces plants ability to photosynthesise.

Can also transmit virus from one plant to another by sucking sap with stylet

Question 14

what is honeydew and how does it affect plants?

Answer 14

a sticky, sugary substance produced by greenfly.

On upperside of leaves enabling growth of a black, sooty mould that reduces plants ability to photosynthesise.

Question 15

Name one disorder of a rose

Answer 15

Rose balling

Question 16

Describe rose balling

Answer 16

flower but often feels soft/slimy to touch.

outer petals become dry/cris in places

bud may drop off or if remains on plant grey mould can develop causing it to rot.

but cannot open and looks unsightly.

Question 17

Name one rose disease

Answer 17

Black spot

Question 18

describe black spot on roses

Answer 18

rapidly enlarging purple/black patch appears on upper surface of the leaf.

leaf tissue around the spot may turn yellow and the leaf may drop off.

small black/scabby lesions can appear on young stems

badly affected plants can shed almost all leaves and vigour of plant is greatly reduced

Question 19

what is a method of control for rose balling?

Answer 19

Plant rose in open site

remove overhanging branches of trees

Good air circulation important so flower buds can dry quickly-achieved by appropriate pruning.

water in evening to avoid hot/sunny conditions

water at base never on flower duds/foliage.

remove affected flower buds ASAP to avoid grey mould occurring

Question 20

describe method of control for black spot on roses

Answer 20

all fallen leaves should be collected and destroyed by burning or local authority (C) in the autumn.

or bury leaves under a layer of mulch

Prune out all stem lesions in spring prior to appearance of new foliage

Older species roses are less affected by black spot

spray with a fungicide

Question 21

what fungicide can roses be sprayed with to control black spot?

Answer 21

teb-ucon-azole concentrate

Question 22

state the life span of club root

Answer 22

it is 20years

Question 23

describe the life cycle of club root

Answer 23

in the presence of susceptible plant roots (brassicas) resting spores germinate and can swim towards the brassica -entering roots through the root hairs.

roots become distorted, swollen and form galls.

the pathogen produces more resting spores in the affected tissue

affected tissue rots/disintegrates and releases spores back into soil

spores lie dormant in the soil until brassicas are planted again

Question 24

describe two control methods for club root

Answer 24

a very long crop rotation

control weeds esp. in brassica family (Capsella bursa pastoris)

Keep soil pH above 7.4 by liming-club root likes acidic soil

avoid transfer of disease via boots/toold/tractor wheels

grow plants in pots before transplanting so there’s a more establishes root system

grow resistance varieties

Question 25

name a resistant variety to club root

Answer 25

Cabbage ‘Kilaton F1’

Question 26

what is meant by the term ‘selective herbicide’? and give named examples

Answer 26

it controls specific weed species leaving the desired crop unharmed.

2,4-D
MCPA
Dicamba
Mecoprop-P

Question 27

how does a selective herbicide work?

Answer 27

leaves the desired crop unharmed.

it will kill broad-leaved (dicotyledonous) weeds in a lawn but not the grasses (monocotyledons)

Question 28

name two perennial weeds found growing in a lawn

Answer 28

Taraxacum officinale (dandelion)
Ranunculus repens (creeping buttercup)
Trifolium repens
Bellis perennis

Question 29

describe how to minimise the risk to peole and the environment when applying herbicides

Answer 29

wear PPE -boots/mask/gloves/coverall

operator must be trained/qualified and follow regulations

apply in correct weather conditions eg: force 2 wind speed (slight breeze) so no off target spray drift occurs

put up warning signs

do early AM or late PM when less animals/insects in area

Make sure people/animals/insects not in area

calibrate sprayer and use correct amount only so excess doesn’t need to be disposed of

apply a buffer zone to protect watercourses/wildlife areas from spray drift/run off

Question 30

describe two effects caused by weeds growing in a garden

Answer 30

compete for light, moisture and nutrients so reduce plant vigour

lack of light leads to yellowing of leaves and etioliated plant growth

weeds make a border look unsightly and disrupt its aesthetic appeal

weeds act as hosts for pest/disease

Question 31

what weeds is a host for club root in brassicas?

Answer 31

Capsella bursa pastoris

Question 32

state one physical method of removing a names perennial weed growing in a herbaceous border

Answer 32

carefully dig out with a fork to remove all perennial roots without damaging existing plants.

eg: Elymus repens

Question 33

what is an active ingredient in a TRANSLOCATED herbicide and name a weed controlled by it’s use

Answer 33

Glyphosate
2,4-D

for Ranunculus repens

Question 34

what is an active ingredient in a CONTACT herbicide and name a weed controlled by it’s use

Answer 34

Acetic

for Poa annua