Unit 3.5: Crop Protection Flashcards
How do weeds effect crop productivity?
They reduce crop productivity mainly due to competition
What are annual weeds?
- They grow from seed and disperse dees in 1 year
- Properties include
- Rapid growth
- Short life cycle
- High seed output
- Long term seed viability
- Examples - chickweed and speedwell
What are perennial weeds?
- `lives for more than 2 years, generally dies in winter and brown in spring
- properties
- Storage organs (bulbs, tubers)
- Vegetative reproduction, only one plant involves, offspring are identical
- examples: dandelion, bramble
Types of plant protection chemicals
- systemic chemicals work by: spreading through the vascular system of plants and prevents growth
- selective herbicides work by: having a greater effect on certain plant species, broad leaves plants e.g being absorbed more through wider leaf surface of the weeds than the narrow leaves of cereal
- systemic insecticides, mollucisides and nematocides spread through the vascular system of plants and kill pests feeding on plants
What advantage is there in applying fungicides based on disease forecast rather than grafting diseased crop?
You have not lost yield to already damaged crops and you are not using fungicide when not necessary
What is biological control?
Biological control involves the introduction of a biological agent which could be a predator, pest, or parasite of the pest
What is integrated pest management?
Integrated pest management combined chemical, cultural and biological controls
What is the risk when using biological control?
The control organism may become an invasive species, parasite prey or be a pathogen of other species
What are problems with using plant protection chemicals?
- There can be bioaccumulation - chemicals can build up to toxic levels over time
- They can be persistent - a high persistence chemical will remain for a long time so if you add more it will build up
