There are different methods of killing an insect. Each has its pros and cons, but here are the best options available to you.
This simple and effective method does not require the use of chemicals. Use it in preference to others when possible. To kill insects by cold, put them in the freezer for at least three days. It is preferable to put only one specimen per container, along with hunting notes and a piece of kitchen paper to avoid condensation.
It is better to keep specimens cold longer than to have the unpleasant surprise of ending up with an insect stirring on an entomological pin. This is especially important for bumblebees and wasps caught in the spring; they have spent the winter as adults and are more resistant to cold.
Among the various products available, ethyl acetate is the winner. This colorless liquid poison is considered harmless to humans, provided it is used correctly.
It takes about 30 minutes to suffocate most small arthropods and about an hour for larger ones. To use ethyl acetate, an asphyxiation chamber must be prepared. It is an airtight container (pot or tube) in which there is a material that absorbs the poison and where the insect to be killed is locked up. The size of the asphyxiating chamber varies depending on the type of insect sought.
If you opt for the tubes, fill them halfway with hardwood sawdust. The wood chips will absorb the poison, while protecting the insects from breakage. To activate the asphyxiating chamber, before hunting, just drop a few drops of acetate into the sawdust. The insects will sink into it and die. It is possible to put more than one insect per tube, especially if they are small.
For glass or clear resistant plastic jars, place an absorbent material (cotton wool, sawdust, felt) at the bottom of the container. Activate the suffocation chamber before the hunt with a few drops of poison.
Stick a label on the ethyl acetate pot and on each asphyxiant chamber with the inscription POISON: ETHYL ACETATE. Store these containers in a safe place.
Insects that will be collected in alcohol can be killed in this liquid. Larvae, soft-bodied adults and small beetles should be dipped directly into 70% or 75% isopropyl alcohol (rubbing alcohol), available from pharmacies.