June 2021 Past paper 2103 Flashcards
state what is meant by the term ‘natural balance’ of pest and predator in a garden situation
When there is an outbreak of a pest, predator numbers increase after a short while.
the predator predates on the pest, and numbers are reduced.
Number of predators reduce when there are less pests to feed on.
Pest not eradicated, but kept to acceptable level
when using pesticides, state potential risks to people and the environment and how they can be minimised
spray drift of chemicals onto nearby crop: spray in calm conditions/windless days.
spray early am/late pm when less activity of bees/beneficial insects etc, and when flowers are not fully open
calibrate sprayer to prevent overdosing and build-up of resistance.
warn members of the public with notices, or fence off areas.
what is meant by physical control when dealing with pests in the garden?
physical action to protect plants, and destroy the pest by hand picking/use of physical barriers
eg: tree guards, cutting off infected parts of plants.
benefits of biological control are:
reduces use of chemicals therefore less chance of a build up in resistance.
reduces human exposure to chemicals and doesn’t harm beneficial insects
benefits of chemical controls are?
when used correctly, targets pest/disease/weed at most susceptible phase of it’s life cycle and reduces crop damage if used as a preventative.
fast acting/pest specific.
limitations of biological control are?
need to know lifecycles of pests
effects may not be immediate, and you could need a controlled environment
limitations of chemical control are:
cause a build up in resistance
damage plants nearby if used incorrectly
toxic to users if not applied correctly,
or leave a chemical residue on crop which are harmful to consumers
life cycle of a slug (learn this one only)
slugs are hermaphrodite-lay batches of spherical eggs (10-15) in moist soil spring-autumn.
Each slug can lay up to 300 eggs.
eggs hatch in moist conditions in less than 2/52 (into immature adults)
immature adults develop into adults, mate fertilising each other.
can overwinter as eggs or young adults and survive frost if protected.
slugs live for 12-18 months
control methods for slugs:
parasitic nematode: apply as drench when soil 5’c and moist-infects it with bacteria and nematode feeds off the slugs body/reproduce in its body.
traps: slug pub sunk into soil near vulnerable plants (check each morning and empty)
can physically remove slugs at night, use pellets containing ferric phosphate
name three physiological plant disorders and a solution for each one:
waterlogging. Improve drainage (by installing drains eg: french or tiles)
frost damage: wrap tender plants in hort. fleece, or move into protected environment.
drought: provide frequent irrigation or mulch with OM
what is meant by a plant disorder?
not caused by pests or disease, it is caused by environmental factors that cause a disturbance of the plants normal functions.
what is meant by the term ‘plant pest’?
an organism belonging to animal kingdom that causes damage to cultivated plants
name two plant pests
vine weevil slug Black bean aphid potato cyst eelworm rabbit deer glasshouse whitefly
methods for minimising the effects of bacterial canker on prunus are?
prune in july/august when bacteria less active
prune all infected material back to healthy wood then apply a wound paint to avoid re-infection.
sterilise all tools between cuts
burn all infected material
grow resistant varieties. eg; Prunus ‘Merton Glory’
what are two facts to consider when selecting plants, which can help prevent plant health problems?
use certified stock from reputable dealer
is plant pest/disease free?
don’t select plants that are pot bound
is there evidence of vigorous growth?
do grafted plants have secure unions?
