Malaise trap

Ethanol damages some flying insects such as lepidopterans, but most people use the malaise trap primarily for hymenopterans and dipterans.

Other dry killing agents including no-pest strips (dichlorvos) and ethyl acetate need to be checked more regularly.

If using a dry agent, a smaller hole results in a faster death, limiting the amount of damage a newly caught insect can inflict on older, fragile specimens.

Also, places where vegetation is growing high around the opening limits the number of flying insects that enter the trap.

Specimens should be collected and removed at dawn and dusk to determine insects caught in daytime versus the night.

Addition of a pan with ethanol at the bottom of the main wall will catch specimens such as beetles that fall before reaching the top.