Pests Flashcards
Describe the damage cause by rabbits.
Nibbling and grazing tender perennials and vegetables
Ring-bark trees in winter, esp fruit trees
Will eat ornamental plants such as roses
State two control methods for rabbits.
Physical:
Rabbit proof fencing (tough wire gauge mesh, max 3cm, buried at least 0.3m below ground and at least 1.5m high.
Tree guards can be placed at the base of the trunk to prevent ring barking.
Cultural:
Ensure gates and fences are closed and secure/mended if broken.
Describe the damage caused by slugs.
Rasping feeding action, eats decaying vegetative matter but also young plants and seedlings, new plant growth, soft fruit (eg strawberries), and roots (eg carrots).
Some plants are more susceptible than others, eg Hostas, Lettuce.
State two control methods for slugs.
Cultural:
Encourage slug predators such as frogs, toads, birds (eg Blackbirds, Starlings) and hedgehogs.
Cultural/Physical:
Regularly picking slugs off of plants, especially effective at night or during wet weather.
Physical:
Beer traps, copper tape etc
Chemical:
Slug pellets (ferric phosphate not Metaldehyde)
Describe the damage caused by Potato Cyst Nematodes.
Feed on the roots of potato and tomato plants, causing chlorosis and stunted growth. Yield is seriously reduced. Plants eventually die, tubers are small and may be rotting.
Roots and tubers will usually show small yellow or reddish cysts which are the dead females bodies containing the eggs ready to hatch.
State two control methods for Potato Cyst Nematodes
Cultural:
Crop rotation (5 or even better 7 year cycle if possible)
Grow early potatoes or resistant maincrop cultivars (‘Maris Piper’, ‘Valor’)
Growing mustard as a green manure before potatoes can also offer some protection, by encouraging particular soil fungi that acts against PCN.
Physical:
Removing and disposing of infected material carefully to avoid spreading the problem (eg burning) .
Describe damage caused by two spotted spider mite.
Spider mites are very small (<=1mm) so difficult to spot initially. They are sap suckers; leaves on affected plants become mottled or display brown patches. Often small webs can be observed amongst the leaves or around the soil.
State two control methods for the two spotted spider mite.
Cultural:
Spider mites occur in hot, dry conditions, so improving ventilation, ensuring plants are well watered (but not too much) and/or damping down greenhouses in hot weather, removes the conditions for their appearance.
Chemical:
Fatty acid or plant oil based chemical treatments can be used (ie wax dissolving controls or blocking the spiracles). Or, pyrethroids (natural or synthetic) can be used.
Describe the damage caused by Aphids (eg Black Bean Aphid or Peach Potato Aphid).
Sap sucker, serious infestations can reduce the vigour of the plant and produce misshapen shoots, flowers and fruits, reducing yield/preventing seed production.
Honeydew can encourage black sooty mould
Aphids can introduce diseases, esp viruses, to the host plant. Eg the Peach Potato Aphid spreads Potato leaf curl.
State two control methods for Aphids.
Cultural:
Ensure plants are not under stress, with plentiful (but not too much) water and nutrients.
Encourage aphid predators such as Lacewings, Ladybirds and their larvae, Hoverfly larvae, and birds (especially tits). Wasps also eat aphids.
Companion planting “sacrificial” plants such as Tagetes spp. can divert aphids away from crop plants.
Physical:
Squashing any aphid infestations immediately will help
Chemical:
Fatty acids, plant oils or Pyrethroid based treatments (natural or synthetic).
Describe the damage caused by Cabbage White Butterflies.
Irregular holes chewed into leaves, starting from the middle of the leaf each side of the main vein. Whole leaves, and potentially whole plant eaten if infestation serious.
State two control methods for cabbage white butterflies and their larvae.
Cultural:
Encouraging predators such as birds (eg Robins, Sparrows, Tits). Wasps also take caterpillars to feed their young, so leaving any wasp nests for a time can also help to control caterpillars.
Cultural/Physical:
Netting to prevent butterflies from landing on the vulnerable plants and laying eggs
Picking off/squashing visible caterpillars or eggs as soon as noticed
Chemical:
Pyrethrin or Deltamethrin can be used, ensuring instructions on timings in relation to harvest are carefully followed.
Describe the damage caused by Vine Weevils,
Adult vine weevils are beetles that chew/bite irregular holes from the edge of leaves - particularly calcifuge plants such as Rhododendron or Camellia spp.
The larvae feed on the roots of plants, (eg Cyclamen) which can cause them to wilt and eventually die.
The dark coloured beetles are nocturnal, so are not often spotted, but the white grubs live in the soil and are more easily spotted if digging.
State two control methods for vine weevils.
Cultural:
Encourage natural predators such as frogs, toads and hedgehogs.
Check new plants carefully for signs of infestation.
Physical:
Pick off beetles at dusk/dawn if spotted.
An overturned pot filled with scrunched up newspaper will attract the adult beetle. These can then be disposed of.
Biological:
Certain nematodes (eg Nemasys) can kill vine weevils at the larval stage.
Describe the damage caused by Glasshouse Whitefly.
Commonly found on sappy herbaceous plants, such as tomatoes or begonias. Sap sucker, can reduce vigour of plant, cover in honeydew and encourage mould growth.
