3.Plant Health Maintenance Flashcards
What is meant by physical control?
State 2 benefits and 2 limitations.
The use of a barrier to protect plants and directly block or destroy weeds or pests.
Benefits:
- Mostly environmental friendly and safe - no chemicals
- Relatively little maintenance needed
- Many prevent pests from reaching the plans
Limitations:
- Can be expensive to set up in terms of obtaining equipment and keeping it maintained
- Do not always get rid of pests
- Potential safety issues relating to incorrect use of equipment, such as to poor training, unsafe removal of infected trees and unsafe burning of infected plant material
Examples of a physical control and considerations
- Barriers – plastic membranes for reducing weeds, allows air and water to pass through it but not weeds. Can be covered with mulch to help visual appeal
- Fleece/mesh netting - protects against pests in garden (Birds/rabbits)
- Fences - Sunk into ground to depth of 30cm, helps prevent larger pests such as rabbit/deer
- Pheromone traps - for luring pests on to sticky sheet (Plum moth end of may) - no risks
- Rodent traps – use high voltage charge or chemicals. Care with children and pets
- E.g Braccica collar - cabbage white fly
What is cultural control?
2 benefits 2 limitations
A procedure or manipulation of the growing environment which result in better control or prevention of plant disorders. Gardeners in their everyday activities remove or reduce organisms in different ways and thus protect the crop.
Benefits:
- Fits in naturally with daily routines
- Can have long-lasting effects such as removal of host weed
- No damage to environment
- No damage to/contamination of food crops
Limitations:
- Time consuming
- Can be slow to act, not immediate
- Not available for all pests
- Gardener has to be alert and knowledgeable
Examples of cultural control and considerations
- Thinking ahead and planting for the environment – PH/nutrient levels available, micro climate
- Thinning out of overcrowded plants - Better aeration can prevent fungal disease
- Removal of weeds - hoeing/weeding with trowel on dry sunny day or Mulching to help suppress them
- Cultivating soil - e.g Rotating/Digging to expose pests to predators such as leather jackets to birds
- Using cultivars which are resistant to disease – eg Sarpo potatoes resistant to blight
- Crop rotation - helps prevent pest build up
- Pruning/removal of dead material - helps prevent/control fungal infections
How are chemical controls supplied?
- Liquid (concentrated or ready to use)
- Wetable powder
- Dusts
- Baits
- Wetting agent - breaks down leaf surface and makes the product stick
- All approved products have a reg no - MAPP
Hazards/risks of chemical control?
Hazards:
- Poisoning - Humans, animals, plants
- Damage to cultivated plants
- Contamination of rivers, streams
- Build up of resistance in pests
Risks:
- Limit applications - to only those situations which justify the control
- Read and understand all instructions and safety procedures before use
- Use proper protective gear - such as rubber gloves
- Do not eat, drink or smoke while applying
How do garden practises disturb the natural balance?
- Monocultures – if a pest or disease is present then it is likely to spread more quickly
- Disturbing the organic content of the soil by removing crops and crop residues and not adding more organic matter will cause a reduction in the soil micro-organisms and soil organisms. Some of these could be useful predators of pests
- Over clearing and overly neat gardens leave no places for beneficial predators to shelter, such as hollow stems of herbaceous perennials
- Pesticides will decrease the presence of natural predators and delay their build up
- Removal of beneficial plants will reduce number of hover fly
How do we restore and maintain natural balances?
- Range of habitats - sunny/shaded/wet
- Attract natural predators - Overgrown areas /nest boxes
- Grow a variety of suitable plants together - Veg crops mixed with annuals to attract beneficial insects
- Manage lawns - Reduce use of herbicides and fertilizers/ Leave areas of uncut grass
- Manage soil - ensure soil organisms and micro-organisms are present/Soil nutrition
Benefits of crop rotation?
Plants belonging to the same family are grown in the same plot, and moved to a different plot every year (3-4 years).
- Root crop, carrot, beet
- Brassicas
- Potatoes, onions
- Peas, beans
- Soil fertility - different plants need different nutrients, avoids depletion
- Pest and disease control - during periods when host plant absent this reduce build-up of spores, eggs and pests
What is meant by Chemical control?
State 2 benefits and 2 limitations.
The use of a chemical substance (organic or inorganic) intended to prevent or kill a destructive week, pest or disease.
Benefits:
- Rapid control
- Pest specific
- Products are easily accessible
Limitations:
- Can be dangerous to humans and animals
- Can result in pest, weed and disease resistance through overuse
- May cause damage to beneficial organisms
What is meant by Biological control?
State 2 benefits and 2 limitations.
The use of a produced or naturally occurring predatory or parasitic enemy to control pests
Benefits:
- Non toxic/ no damage to beneficial insects/pets/humans
- No build up of pest resistance
- Targets specific pests
Limitations:
- Gardener needs knowledge of the pest and the predators life cycle
- Slow acting and crops may already be damaged if applied too late
- Pest has to be in large enough numbers to support predator
- Introduction of the wrong bio control could subsequently kill off beneficial organisms
Examples of a biological control and considerations.
- Indigenous/exotic
- Predators eat pests, parasites lay eggs in pests (nematodes)
- Hedgehogs eat slugs - Consider providing a hedgehog house or leaving piles of autumn leaves for them to hide in
- Frogs eat aphids and crawling insects - Consider adding a pond
- Garden birds - blue tits, eat caterpillar and aphids - add bird box to garden
- Hoverfly grubs eat aphids - Consider planting pollinated plants to encourage them e.g Romneya Couteri
- Cinnabar moth - caterpillar eats weeds, ragwort
What is a pesticide
Pesticide is the name given to all methods of chemical crop protection
- Herbicides for weeds
- Insecticides for insects
- Fungicide for Fungi
