Pests Flashcards
State what is meant by the term plant pest.
An animal, insect, organism that is of detriment to the plants health.
Describe the damage done by rabbits
And 2 methods to minimise
Vegetables, annuals and herbaceous bedding plants are all a target.
Herbaceous shoots nibbled to the ground.
Bark gnawed at the base of trunks and cambium removed, interrupting the xylem and phloem.
Holes are dug.
Physical control of fencing and netting is effective. Electric fences and tree guards.
Cultural control - plant plants that deter such as snowdrops
Shoot them.
Describe the damage done by cabbage white butterfly
And 2 methods to minimise
Leaves of cabbages, cauliflowers, Brussels sprouts, nasturtiums etc are gradually eaten away. Skeleton leaves may result.
Larvae and excrement on leaves.
Cover crops with fine netting making sure it does not touch plants.
Pick off larvae
Encourage blue tits by building nest boxes
Spray with insecticide containing pyrethrum. Pyrethrins.
Outline the lifecycle of the cabbage white butterfly.
Adults lay yellow eggs on underside of brassica leaves.
Eggs hatch 4-8 days later into caterpillar larvae which feed on the leaves.
2 weeks later they form a pupa and 10 days later an adult emerges. (but can overwinter)
Describe the damage done by Black bean Aphid
And 2 methods to minimise
Most commonly damaged are broad beans.
Dense swarms of aphids on soft new growth and flowers.
Shoots weakened by the aphids sucking phloem out of shoots.
Aphids secret sugary liquid (honeydew)that can get infected by sooty mould.
Growth is affected and seed production dramatically reduced.
Control biologically by encouraging ladybirds, lacewings, hoverflies.
Physical hand squishing
Spray with insecticide containing Pyrethrum or natural fatty acids.
Outline the life cycle of black bean aphid.
Eggs overwinter on woody host e.g. the Spindle tree or Philadelphus
In spring female nymphs emerge, feed on winter host.
At maturity they grow wings and fly to summer host such as beans. Females give birth to many live young.
In Autumn these live young include males and along with females they fly back to winter host to mate and lay eggs.
Describe the damage done by Peach Potato Aphid
And 2 methods to minimise
Greenfly.
Using their sucking stylet aphids inject a digestive juice which distorts tissues
They secret honeydew which blocks stomata, attracts sooty mould which slows photosynthesis and therefore growth.
Also transfer viruses such as Leaf Roll.
Control by introducing organisms such as ladybirds, lacewings, hoverflies.
Choose an insecticide containing Pyrethrum or fatty acids.
Describe the damage done by
Two spotted spider mite
And 2 methods to minimise
Piercing and sucking mouth parts inject poison into Leaf cells, causing localised death. This shows as a fine yellowish mottling of the Leaf. Eventually lose all green colour, dry up and drop off.
Severe infestations show fine silk webbing on the plants.
Chemical - Spray insecticides containing fatty acids.
Biological - introduce predatory mite Phytoseiulus persimillis
Cultural - check all new plants coming into glasshouse. In winter clean and disinfect everything in glasshouse and glasshouse itself in winter.
Name the predatory mite used as biological control for red spider mite
Phytoseiulus persimilis
Can’t be used in conjunction with any other chemicals other than organic whilst awaiting delivery.
Describe the damage done by glasshouse whitefly
And 2 methods to minimise
Attacks solanum persicum and other greenhouse plants.
When plant disturbed clouds of small white winged insects fly up.
Flat oval scale like nymphs on under side of leaves
Honeydew on foliage. Which attracts black sooty mould
Biological - Encarsia Formosa parasitic wasp
Sticky yellow sheets hung above plants to trap whitefly.
Quarantine new plants.
Chemical - Pyrethrin and fatty acids
Name the parasitic wasp used as a control for greenhouse whitefly.
Encarsia Formosa
Outline the lifecycle if glasshouse whitefly.
Adult lays eggs Eggs - 200 minute white rugby ball shaped in circular pattern on under side of the leaf. Eggs turn black Hatch into nymphs (crawlers) which then turn into scales 3rd instar Pupa Adult Lays eggs agin 3 days later.
Describe the damage done by Vine Weevil
And 2 methods to minimise
Damage grape vines, and tubers such as cyclamen and begonias
Irregular shaped notches on Leaf margins in summer
Plants wilt and die during autumn -winter due to white grubs eating roots.
Cultural - encourage natural enemies such as birds shrews frogs etc.
Sticky traps
Picking/shaking off adult weevils at night in summer.
Biological - nematodes
Chemical - acetamiprid for ornamental plants - bug clear ultra vine weevil killer
Outline the life cycle of the vine weevil
Adults feed on leaves and then lay eggs in august in soil or compost next to roots of cyclamen or begonia.
Larvae emerge white and legless with brown head usually lying in c shape.
Pupate in soil in December and adult emerges.
Describe the damage done by slugs and 2 methods to minimise
Feeds with radula and can scoop out cavities.
In moist warm weather damage is done to leaves of hostas etc.
Completely eat young seedlings
Irregular holes in plants
Slime trails
Biological - Nemaslug nematodes watered in in spring
Place traps such as scooped out citrus halves, jars filled with beer
Hand pick with torch.
Encourage frogs and birds
Copper tape around pots
