| A | B |
|---|
| weed (n) | a plant that grows where it is not wanted |
| yield (n) | the amount of useful plant material produced by commercial growers |
| competition (n) | simultaneous demand by 2 or more organisms for limited resources |
| weedkiller / herbicide (n) | a substance that kills weeds |
| selective weedkiller (n) | a substance that kills weeds but does not kill crops or grass |
| crop pest (n) | an animal that damages a crop and reduces the yield |
| pesticide (n) | a substance that kills pests |
| insecticide (n) | a substance that kills insects |
| biodegradable (adj) | a material that decays naturally without leaving a harmful residue behind |
| persistant pesticide (n) | a pesticide that does not break down in the environment |
| aphid* (n) | an insect that feeds on the sugary plant sap; a.k.a. plant louse or greenfly |
| DDT* (n) | a chemical pesticide that was widely used in the 1950-1960s |
| bioaccumulation* (n) | accumulation of a substance in the tissues of an organism |
