Crane Fly Lawn Solutions

CRANE FLY
Solutions
The Problem
Crane flies can be found in the Pacific Northwest, Northeast, the upper Midwest and Eastern Canada. Two species exist,
the Tipula paludosa (European crane fly) and Tipula oleracea (common crane fly). The larvae, also commonly referred to as
leatherjackets, will feed on most cool-season turfgrass species. They may scalp turf during foliar feeding and also damage
the root systems via underground feeding. Turf symptoms appear as yellowing, thinning areas and progress rapidly to large
dead spots. The greatest damage is generally observed in late spring. Crane flies thrive in moist soils, favor areas with thatch
buildup and prefer mild winters and cool summers.
What To Look For
The Solution
The adult crane fly has long legs and looks like a large
mosquito, but it does not bite or sting. They complete
one (T. paludosa) or two (T. oleracea) generations per year
with the emergence of adults from the soil in grassy areas
occurring in early spring (T. oleracea) or August – September
(both species). Females mate and lay eggs in turf areas
within 24 hours after emerging. These eggs hatch into
small, gray-brown, worm-like larvae, commonly called
leatherjackets because of their tough skin. The larva grow
to nearly an inch long and look like a brown caterpillar
with no head or legs. Leatherjackets feed on the roots
and crowns of clover and grass during the fall. They
winter in the leatherjacket stage, but do not feed during
this time. As the weather warms in spring, leatherjackets
resume feeding. Damage may become especially noticeable
in March and April. In warm winters, damage can be severe
as early as mid-December or January. During the day,
leatherjackets mostly stay underground, but on damp,
warm nights, they come to the surface to feed on the
aboveground parts of many plants. Leatherjacket feeding
stops around mid-May. They spend June and July in a
non-feeding pupal stage just below the soil surface. From
August – September, pupae migrate to the surface, and
adult crane flies emerge.
In early spring, survey the turf area by selecting three or four
random spots, 6 x 6 inches each. Dig up the top layer (1-2
inches) and tear it apart to count larvae. They usually are
located at the base of the vegetative layer (thatch) or within
2 inches of the soil surface. Multiply the number of crane fly
larvae you find in each sample by 4 to estimate the number
per square foot. If this number exceeds 25-50 per square
foot and the turf is thin, consider a curative insecticide
application. If the lawn is in poor condition, treatment at
lower levels (10-15 larvae per square foot) may be
necessary. Healthy, vigorously-growing lawns have been
known to have in excess of 50 larvae per square foot and
show no damage.
A good fertilizer program may mask the effects of crane
fly feeding. Other observations indicate that drought stress
at the time of egg lay may significantly reduce larval
populations. Egg survivability is dependent upon adequate
soil moisture. Turning off the irrigation system or reducing
the run times shortly after Labor Day will often create enough
drought stress to reduce larval populations without causing
damage to the lawn.
For lawns with a history of crane fly damage, preventive
applications of Merit® can be made in the late fall
(September – October) at the time of egg laying or when
larvae are smaller and still active at the soil surface.
Otherwise curative applications of Sevin® SL can be made
in the spring, once high populations or feeding damage
of European crane fly is detected. If populations of
common crane fly are present, a late fall treatment is
recommended as it would target both species; the
common crane fly completes two generations per year
and susceptible larval populations are difficult to target
in the spring.
CRANE FLY Solutions
SOLUTION1
RATE (per 1,000 sq ft)
Merit 0.5 G
1.4 - 1.8 lbs
Merit 2 F
0.46 - 0.6 fl oz
Merit 75 WP
3.0 - 4.0 tsp
Merit 75 WSP
1.6 oz (1 packet) per 8,250 - 11,000 sq ft
Merit on Fertilizer
3.5 - 4.5 lbs
Please check the label as the rate will vary according to
the fertilizer carrier and percentage of imidacloprid.
Sevin SL
6.0 fl oz
APPLICATION INTERVAL
For optimum control, make
application prior to egg hatch.
Apply in early spring; irrigate
turfgrass after treatment.
See the product labels for complete use and instructions. Always read and follow label instructions carefully.
1
Adult crane flies are visible in the fall but cause no damage to the turf.
Photos: Tom Cook (retired), Oregon State University.
Crane fly larvae at the 1st, 2nd and 3rd instar. Third instar are commonly
referred to as leatherjackets.
Photos: Tom Cook (retired), Oregon State University.
If left unchecked, the 3rd instar can cause significant damage in just weeks
by feeding on the turf leaf tissue.
Photos: Tom Cook (retired), Oregon State University.
Larvae usually stop feeding in late-spring and begin moving downward as
deep as 3 inches below the soil surface. Full grown larvae remain inactive
until pupating in late summer/early fall.
Photos: Tom Cook (retired), Oregon State University.
ALWAYS READ AND FOLLOW LABEL INSTRUCTIONS CAREFULLY.
Bayer CropScience LP, Environmental Science Division. 2 TW Alexander Drive, Research Triangle Park, NC 27709. 1-800-331-2867. www.BackedByBayer.com.
Bayer, the Bayer Cross, Merit and Sevin are registered trademarks of Bayer. Please verify state registration of these products in your state before selling,
using or distributing. ©2015 Bayer CropScience LP. 15BPG-012-43