When a plant is damaged by an insect pest, such as a caterpillar, it does not just sit there – the wounding leads to the production of volatile chemicals. These have three functions:
1) they ‘switch on’ chemical defences in the damaged plant;
2) they send a signal to other plants that damage is occurring in their immediate environment; and
3) the same signal tells beneficial insects such as ladybirds that food for them (i.e. the pest) is available to them upwind.
Of the chemicals involved, a key one is methyl salicylate which, incidentally, is a key ingredient of some products that we use to ease muscle pain, such as after sporting activities. Use the sachet provided to attach to a tree or a stick in your vegetable plot and observe good insects being attracted to that location.
|Dimensions||145 × 100 × 2 mm|