3.3 Crop Protection Flashcards
What is the productivity of crops affected by?
competition with weeds
What is a weed?
A weed is defined as simply a plant growing in the wrong place
A field planted with rows of potatoes may be contaminated with weeds growing both between the rows of potato plants, and between the individual plants themselves
TOPTIP
Plant productivity is the rate of new material (biomass) per unit area per unit of time factors limiting the rate of photosynthesis and therefore plant productivity include light intensity, carbon dioxide concentration and temperature.
TOPTIP
When two or more members of a community need the same resources which are in short supply competition occurs. Plants compete for light, water, minerals and root space.
Crop weeds that grow among crop plants reduce what?
reduce yields by competing for resources needed by crops
What two types of plants can weeds be?
annual or perennial plants
Adaptations of annual weeds?
sexual reproduction short life cycle (one year) rapid growth high number of seeds produced dormant seeds remain viable for long periods of time
Examples of annual weeds?
goosegrass, knotweed, sheperd’s purse
Adaptations of perennial weeds?
asexual production long lifecycle (two years +) broken pieces of plant can root and grow into individual plants storage organs provide food for plant in autumn/winter
Examples of perennial weeds?
couch grass, nettles, buttercup
Examples of pests?
Insects cause leaf damage such as greenfly, blackfly and leatherjackets
Nematodes are roundworms in soil that attack roots and storage organs
Molluscs like slugs and snails damage leaves
Examples of Diseases?
Fungi - yellow rust on leaves of cereal plants; brown rot on stone fruits, peaches and plums
Bacteria affect stems, roots and leaves and cause leaf spot, blight and galls
Virus - yellow mosaic of lettuce leaves caused by lettuce mosaic virus reduces photosynthesis
TOP TIP
A vector is any agent such as an animal which carries and transmits a pathogen into another living organism
Some invertebrates are also vectors of fungi bacteria or viruses and so are responsible for transmitting plant diseases
TOPTIP
A weed is a plant growing in the wrong place
TOPTIP
Weeds within a growing crop can
compete with crop plants for nutrients
contaminate crop at harvest time
release chemicals into the soil which inhibit the growth of the crop plant provide habitats for pest species
What are methods that can control crop pests?
prevention
cultural control
chemical control
Explain the method prevention?
preventing the introduction of weeds to the soil can be easier than removing established weeds
Good practice includes the removal of weed seeds and vegetative structures from tools and machinery used to prepare the soil, ensuring seeds are certified to be free of weeds and controlling weeds in the surrounding areas
Explain cultivation control?
cultivation and good management of soil help to prevent the build up of weeds, pests and diseases.
There are 4 methods of cultivation these are?
Ploughing
autumn sowing
weeding
crop rotation
Describe Ploughing?
This destroys perennial root systems in the soil and clears the field of any previous crop residue which may harbour some pests and plant diseases
Describe autumn sowing?
seeds planted in the autumn allow a crop to become established before a surge of pests and diseases in the spring, improving crop tolerance
Describe weeding?
Growing weeds are removed by cultivation between rows of crop plants
Describe crop rotation?
Planting different crops in each field each year helps to break the lifecycle of pest species
What are herbicides, pesticides and fungicides?
chemicals that are sprayed onto a growing crop