Maintaining Plant Health Flashcards
1.1 What is meant by Physical Control?
State TWO benefits and TWO limitations of using this method of control.
Material, mechanical or hand control where weed or pest is directly blocked or destroyed.
Physical control is the use of direct physical action to protect plants or destroy pests, diseases or weeds using e.g. physical barriers, hand picking of pests and cutting off infected material
Benefits:
- Remain in place for a long time e.g. rabbit-proof fencing
- Relatively little maintenance needed
- safer for the environment than potentially harmful chemicals
- safer for the operator than chemicals
- no risk of developing resistance
Limitations:
- Can be expensive to set up in terms of obtaining equipment and keeping it maintained
- Potential safety issues relating to incorrect use of equipment, such as unsafe use of equipment due to poor training, unsafe removal of infected trees and unsafe burning of infected plant material
- Requires tools using hand methods to be kept scrupulously clean to avoid spreading pests and diseases
- knowledge of pest life cycle is required
- physical barriers can make access to crops cumbersomecrop can be damaged by
- removing affected materialcrop must be closely watched and action taken swiftly once pest identified
1.1 Describe ONE example of Physical Control and how risks to people and the environment can be minimised.
Barriers – plastic membranes for reducing weeds but need to be disposed of properly and not burnt
Pheromone traps for luring pests
Rodent traps – care with children and pets
- Removing and burning stumps and roots affected by honey fungus
- Removing and burning rose prunings and cuttings affected by blackspot
1.1 What is meant by Cultural Control?
State TWO benefits and TWO limitations of using this method of control.
1.1 A procedure or manipulation of the growing environment. Gardeners in their everyday activities remove or reduce organisms in different ways and thus protect the crop.
Cultural control is the use of good horticultural practices to reduce the incidence of pests, diseases, weeds and plant disorders
Where possible, prevention is better than cure. Prevention mainly involves good garden practice and good hygiene; often referred to as cultural controls.
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
- Not available for all pests
- Many only available for glasshouses
- Control may itself become a pest
Benefits:
- Very simple to use, fits in with daily routines and has long-lasting effects
- Can be time consuming
- With regards to crop rotation helps maintain healthy soils in terms of structure, fertility and reduction of soil erosion
Limitations:
- Requires knowledge of the techniques and procedures for crop management
- Sole use will not suppress all pests and disease. Often required to be used in combination with other methods.
- Some diseases last longer in soil than rotation cycle
1.1 Describe ONE example of Cultural Control and how risks to people and the environment can be minimised.
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
1.1 What is meant by Biological Control?
State TWO benefits and TWO limitations of using this method of control.
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
- avoids use of chemicals and build up of resistance
- avoids direct damage to beneficial organisms in the food chain
- avoids physical damage to the plant
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
- there must be a sufficient population of pest present to support predator, pathogen or parasite population
- predator may require specific temperature to thrive, limiting use to glass houses
- some damage may have been done before pests is brought under control
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1.1 Describe ONE example of Biological Control and how risks to people and the environment can be minimised.
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
1.1 What is meant by Chemical Control?
State TWO benefits and TWO limitations of using this method of control.
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
- used correctly chemical control targets pest, disease or weed at most susceptible time
- may reduce damage to crop if applied early
- may reduce time and labour cost of crop production
- generally quick and simple to use
- can be used preventatively
- can be fast acting and pest specific
Limitations:
- Can be dangerous to humans and animals
- Can result in pest, weed and disease resistance through overuse
- May cause damage to beneficial organisms
- pests and diseases may build up resistance to chemicals
- may harm beneficial organisms
- may leave harmful residue on food crops
- expense
- operator needs to be wear protective clothing
- may damage plants in the vicinity
1.1 Describe ONE example of Chemical Control and how risks to people and the environment can be minimised.
- read and follow instructions carefully
- do not apply in adverse weather e.g. wind
- do not apply in the middle of the day to avoid harming pollinators
- wear appropriate personal protective equipment
- avoid contaminating water courses
- store in original container in lockable container
- avoid pesticide where possible
- identify pest correctly
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
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
1.2 Explain the importance of natural balances in plant protection to include beneficial organisms
(ladybirds, lacewings, hoverfly, hoverfly larvae, frogs, hedgehogs, birds).
Explain the importance of natural balances in plant protection to include beneficial organisms:
This is important as it helps the ecosystem self-regulate. Healthy plants are much more likely to resist attacks from pests and diseases. If the soil, water and air is healthy (with many living organisms) then it will have a positive effect on the plant and, in turn, the wildlife surrounding.
1.2 Give TWO examples of how beneficial organisms can be encouraged.
Give TWO examples of how garden practices can disturb these balances, including the use of pesticides.
- use of nitrogenous fertilisers can make growth soft and susceptible e.g. to aphids
- overuse of pesticides will kill beneficial organisms and may lead to resistance
- not rotating crop e.g. potatoes to protect against potato cyst eelworm
- introducing infected plants, equipment or material into the garden
- cutting hedges during nesting season for birds
- composting infected or diseased material
- timing our chemical applications can reduce impact
- Dirty tools, boots and tyres can spread disease
- Growing plants from other climates or not suited to conditions
- Frequent soil disturbance
- Lawns are monocultures and will provide little to beneficial organisms.
Describe TWO methods that can be used to restore and maintain the natural balances to minimise the need for pesticides
- hedgehogs for slugs
- ladybirds for black bean aphids
- lacewings for thrips
- thrushes for snails
- blue tits for aphids
- -
- use plants that attract pollinating insects
- avoid pesticides that may affect beneficial organisms
- install log piles andnest boxes to encourage predators eg hedgehogs, birds
- provide water in a pond with shallow sides for frogs that eat slugs
- leave food for birds e.g. blue tits
