How to Manage Pests
UC Pest Management Guidelines
European Crane Fly: Tipula paludosa
Common Crane Fly: Tipula oleracea
In this Guideline:
Adult crane flies emerge from the soil beneath turfgrass,
pastures and other grassy areas in late summer and fall. The adults have very
long legs and resemble large mosquitoes. Females mate and lay eggs in grass within
24 hours of emerging. Eggs hatch into small, brown, wormlike larvae that have very tough
skin and are commonly referred to as "leatherjackets". The
leatherjackets feed on the roots and crowns of clover and grass plants during
the fall. They spend the winter as larvae in the soil; when the weather warms
in spring, they resume feeding. During the day larvae mostly stay underground,
but on damp, warm nights they come to the surface to feed on the aboveground parts
of many plants. When mature, the larvae are about 1 to 1-1/2 inch long. Around
mid-May they enter a nonfeeding pupal stage and remain just below the soil
surface. In late summer, pupae wriggle to the surface and the adults emerge.
There is one generation a year.
In California crane flies have primarily been found at damaging
levels in the Humboldt and Del Norte counties and do not appear to be a problem
on turfgrass in warmer, inland areas. All cool season turfgrass species appear
to be susceptible.
The larvae are the damaging stage of this pest. They feed on the
roots, crowns, and aboveground portions of grass plants. Healthy, vigorous
turfgrass can withstand low to moderate populations. Damage often becomes
noticeable in March and April and appears as dying patches of turfgrass. Weeds
may invade areas of dying turfgrass. Although the adults resemble mosquitoes,
they do not bite or sting; it is believed that they feed primarily on plant
nectar. Populations of crane fly larvae have been reduced by as much as 50%
during the winter months and between March and May as a result of predators
such as birds and predaceous ground beetles and other natural causes.
A vigorously growing, well-maintained turfgrass can easily
recover from the feeding of crane fly larvae, even when the populations are
fairly high. Monitor for crane fly larvae if the turfgrass is exhibiting areas
of poor growth. Adequate nitrogen fertilizer is essential.
Drenches with the nematode Steinernema feltiae may give up to 50% reduction if properly applied.
Proper fertilization and irrigation are important factors in
determining how much feeding by crane fly larvae the turfgrass can tolerate.
Well-maintained turfgrass has been observed to withstand populations of crane
fly larvae that averaged 40 per square foot, whereas unthrifty turfgrass may
exhibit damage with as few as 15 larvae per square foot. Application of
nitrogen in the spring may reduce damage. Provide better drainage for
chronically wet areas and redue irrigation. Craneflies thrive in wet soils.
Growing turfgrass species that require full sun in shady areas
can reduce plant vigor and promote survival of crane fly larvae. In areas of
low sun, consider a turfgrass species that prefers shade or a groundcover.
Remove excess thatch; it provides an ideal habitat for crane fly
larvae, which feed mostly just below the thatch. Aerify the soil to stimulate
root development and improve the movement of water and nutrients into the soil.
Reseed bare areas of turfgrass so that weeds do not invade.
and Treatment Decisions
Monitor crane fly larvae in spring when the weather has warmed,
generally in March. Samples can either be taken with a 4-inch diameter cup
cutter or by digging up a 6" by 6" area of turfgrass about 1 to 2
inches deep. Larvae will usually be found at the base of the vegetative layer
(thatch) or in the soil just beneath the plants. Pull apart the samples and
count the number of crane fly larvae. If a 4-inch
diameter cup cutter is used, multiply the number of larvae in each core by 11.5 to get the number
of larvae per square foot. If a 6" X 6" area is sampled, multiply the
number of larvae by 4 to get the number of larvae per square foot. Sample three
or four locations and determine the average number of larvae/sq. ft. If damaged
areas of turfgrass are sampled, take the sample from the edge of damaged area
and not from bare patches, where the larvae would no longer be present.
Continue monitoring through April, if no damage is observed by then, no further
action is needed.
Research has not been conducted in California on treatment
thresholds, but in Washington, the treatment threshold is 25 to 50 larvae per
||Amount/1000 sq ft**
materials are listed in approximate order of usefulness in an IPM program,
taking into account efficacy and impact on natural enemies and the
environment. Not all registered materials are listed. Not all registered pesticides are listed. Always read label of product being used.
||MODE OF ACTION GROUP NUMBER1: 1A
||COMMENTS: Water or irrigate turf soon after treatment.
||MODE OF ACTION GROUP NUMBER1: 3
||COMMENTS: Not for use on sod farms or in commercial seed production. May cause water quality issues.
||COMMENTS: Store nematodes properly
before use as directed. Apply to warm, moist, but not soggy soil. Several
irrigations may be needed during 2 weeks after application to keep soil moist. Apply during the coolest time of day in hot areas.
UC IPM Pest Management Guidelines: Turfgrass
UC ANR Publication 3365-T
Insects and Mites
M. L. Flint, UC IPM Program, UC Davis
M. A. Harivandi, UC Cooperative Extension, Alameda County
H. K. Kaya, Nematology, UC Davis
Acknowledgment for contributions to Insect and Mites:
J. Hartin, UC Cooperative Extension, San Bernardino County
R. S. Cowles, Connecticut Agricultural Experiment Station, Windsor, CT
K. Kido, Entomology, UC Riverside
H. S. Costa, Entomology, UC Riverside
D. D. Giraud, UC Cooperative Extension, Humboldt/Del Norte counties
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