Knowing is half the battle when it comes to fighting Earwigs in our gardens.

By Rincon-Vitova Insectary

Earwigs 

Easily recognizable pests in the garden and active at night, earwigs hide in tight, dark, moist places during the day. True omnivores, they actually are important predators of aphids, insect eggs, but will eat almost all parts of flowering plants, especially soft tissue, like newly forming buds in cannabis.  

Identification 

The adult body is about 3/4 inch long and reddish brown.  

Most species have wings under short, hard wing covers, but they seldom fly.  

Two appendages that resemble forceps at the tail end of body are used for defense, mating, and capturing prey. 

Life Cycle 

Females lay masses of eggs shallow in the soil during fall and winter.  

Generally there is one generation a year, but females produce two broods. 

Monitoring 

Soft tissue damage looks similar to snail damage – Look for the presence of slime trails to distinguish between the two. 

To confirm that earwigs are causing the damage, go out at night with a flashlight. 

Leaves will appear jagged and full of holes when it is earwig damage.  

Plants will become ragged overnight, and some leaves will only be partially eaten.  

A scattering of black excrement will often be present, also. 

Damage often occurs after rainy weather, which forces earwigs to seek dry shelter and climb up into plants and leaves. 

Cultural Practices 

Reduce hiding places: loose clods of soil, boards, or dense growth of vines or weeds. 

Manage irrigation/watering to reduce surface moisture (not a problem in dry areas, earwigs need moisture & shade). 

Homemade oil traps: Tuna or cat food cans buried to soil surface: Add 1” oil and a drop of Fish oil or tuna oil 

Equal parts soy sauce and olive or vegetable oil, put it in a small plastic container, and secure the lid. Punch holes around the top of the container, near the lid. Bury container in the soil just up to the holes.  

Homemade harborage: rolled up newspaper, bamboo/arundo grass sections/ hose sections. Dump into soapy water 

Dust with Diatomaceous Earth: these jagged particles cut the insects and expose to desiccation & disease. It will need to be reapplied as it gets wet. 

Double sided tape or sticky pest barrier around pots to prevent movement into plants. 

Apply Petroleum jelly around the stems of plants, or around a protective cup; earwigs won’t crawl over it 

Alcohol acts as a surfactant, or wetting agent, it penetrates insects’ waxy exoskeleton and kills on contact. Isopropanol (rubbing alcohol) works fine, but make sure it doesn’t have additives.  

Ethanol (grain alcohol) seems to work best. Comes in 70% strength or 95% strength   

DIY insecticidal sprays: Mix equal parts 70% alcohol and water  

  Mix 95% alcohol: 1 part alcohol to 1 ½ parts water 

Avoid using pesticides: Carbamates (carbaryl). These materials are highly toxic to natural enemies and pollinators. 

Bio-Control: none 

Summary of Strategies 

Reduce habitat and manage irrigation 

Oil Traps – emptied and refilled regularly 

Newsprint Harborage Traps – emptied in the mornings 

DE dusted around plants 

Petroleum jelly barriers/glues to prevent them from reaching plants 

Alcohol Sprays 

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