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How to Manage Pests
UC Pest Management Guidelines
Turfgrass
Crane Fly
Scientific name: Tipula paludosa
(Reviewed 6/03,
updated 6/03)
In this Guideline:
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DESCRIPTION OF THE PEST
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.
SUSCEPTIBLE SPECIES
In California crane flies have primarily been found at damaging levels in the
Humbolt and Del Norte counties and do not appear to be a problem on turfgrass
in warmer, inland areas. All turfgrass species appear to be susceptible.
DAMAGE
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.
MANAGEMENT
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.
Biological Control
Drenches with Steinernema nematodes may give up to 50% reduction if
properly applied.
Cultural Control
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.
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.
Monitoring 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.
Research has not been conducted in California on treatment thresholds, but in
Washington, the treatment threshold is 25 to 50 larvae per square foot.
| Common name |
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| (trade name) |
Amount/1000 sq ft**
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Many of these products are available for use by licensed applicators only and cannot be used by home gardeners.
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| A. |
CARBARYL* |
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(Chipco Sevin) 80WSP |
6 fl oz |
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COMMENTS: Water or irrigate turf soon after
treatment. |
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| B. |
CHLORPYRIFOS |
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(Dursban Pro) |
3-6 fl oz |
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(Dursban) 50W WSP* |
1.5-3 oz |
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COMMENTS: For use in turfgrass production
and on golf courses only. For best results, turf should be moist at
time of treatment. This product is highly toxic to birds and aquatic
invertebrates. State and federal agencies have determined that waterways
have been impaired by the use of this material. Do not apply in such
a manner that it will get into storm water drains. |
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| C. |
STEINERNEMA CARPOCAPSAE |
25 million |
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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. |
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Apply in 25 gal water/1000 sq ft |
| * |
Permit required from county agricultural commissioner
for purchase or use. |
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UC IPM Pest Management Guidelines: Turfgrass
UC ANR Publication 3365-T
Insects and Mites
H. S. Costa, Entomology, UC Riverside
R. S. Cowles, Entomology, Connecticut Agricultural Experiment Station, Windsor, CT
M. A. Harivandi, UC Cooperative Extension, Alameda Co.
J. Hartin, UC Cooperative Extension, San Bernardino Co.
H. K. Kaya, Nematology, UC Davis
Acknowledgment for contributions to the insect and mite section:
K. Kido, Entomology, UC Riverside
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