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Identification

Adult crane flies superficially resemble large mosquitoes with very long legs. Larvae are brown and wormlike with very tough skin; they resemble caterpillars such as cutworms but lack legs. Mature larvae are 1 to 1-1/2 inches (2.5 - 3.8 cm) long.

Hosts

All turfgrass species

Damage

In California, damage has been found primarily in the Humbolt and Del Norte counties. Crane flies are a problem along the Pacific northwest coast but rarely cause damage in warmer, dryer inland areas in California. Affected turf appears as dying patches. Feeding damage may be apparent on roots, crowns, and aboveground portions of grass plants. Weeds may invade areas of dying turfgrass. Adults do not damage grass or feed at all. Although sometimes called "mosquito hawks," crane flies do not feed on mosquitoes or other insects or harm people.

Monitoring information

Monitor for crane fly larvae during the spring when the weather is warm. Dig around the thatch layer just beneath the plants and look for brown larvae with tough skin. Sometimes the shiny, leathery, empty pupal cases can be found on the turf surface after adults have emerged.

Management

Turf can easily recover from crane fly feeding if properly maintained. Follow recommended irrigation and fertilization practices for your turf species. Crane flies are often associated with wet or waterlogged areas. Remove excess thatch and aerate to stimulate root growth and improve water and nutrient movement into the soil. Reduce shady areas by pruning back tree branches to allow more light to reach the turf during the early morning and late afternoon. Beneficial nematodes may help reduce high populations.