Plant Health Flashcards
what is a herbicide
a compound used to kill or control weeds.
why is a lot of food not available for consumption - 3 reasons
- destroyed by pests in fields
- spoiled in storage (insecticides and antioxidants)
- animals are susceptible to diseases and parasites .
what is a selective herbicide
kills weeds but not crop.
what is a non-selective herbicide ?
kills all plants
give an example of a selective herbicide and draw it
2,4,5 T
benzene ring with3 chlorines and O-CH2COOH attached
chlorine containing chemicals can be very persistent in the environment. what is an example of a chlorine free selective herbicide ?
fusillade
- more biodegradable
- more effective and therefore lower application needed.
what is an example of a non-selective herbicide ?
glyphosate
what’s an example of a growth control regulator for plants
auxin - its a hormone for plants .
why do we use growth control for plants?
- reduce the need to trim fruit tress.
- prevent wind flattening of cereals
- control of growth of forests under power lines.
how does selective insecticides work ?
exploits the difference between the metabolism of insects vs higher animals.
what bond in the selective insecticides are vital as to not harm humans
P=S
only insects can transform P=S to P=?
P=O, which can kill them.
what is DDT ?
the fist synthetic insecticide .
good at killing insects on plants an controling insect born diseases such as malaria .
not used much now due to persistence in the environment
what are the 5 types of chemicals which protect food-producing plants 0- with examples
- pesticides - insecticides and rodenticides
- fungicides - copper based and systematic
- herbicides - glyphosphate and atrazine
- fertilisers - N, K and P
- growth regulators - auxins and PP333
draw the structure of phenoxyacetic acid which is needed for an effective herbicide
benzene , O, =O, OH
