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.
All turfgrass species
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.
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
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.