Crane Flies (Leather Jackets)
- Scientific Name: The European crane fly, Tipula paludosa (Meigen), and the marsh or giant common crane fly, T. oleracea are perennial pests, but other species of native crane flies may be associated with turf damage across North America and other places around the world. [Phylum Arthropoda: Class Insecta: Order Diptera: Family Tipulidae]
- Common Names: crane flies, leather jackets, daddy-long-legs (mainly in Europe as this name is associated with an arachnid in North America).
- Climatic Zone: subtropical and temperate
- Geographic Distribution: European crane fly species were first introduced into British Columbia, Nova Scotia, Washington and possibly Oregon, but they have been detected in eastern Canadian provinces and around the Buffalo, New York areas. They are natives of England and northern European countries. Other species of crane fly larvae may be found in turfgrass across North America and other places around teh world, but most are considered nuisances more than pests.
- Damaging Stage: larvae, though adults cause alarm in those who think they are giant mosquitoes.
- Hosts: Virtually all grasses may be attacked, but the European species seem to be only tolerent of cool-season conditions.
- Damage Symptoms: Bare areas, sparse growth, lodging of seed stalks and tall grasses. Depending on the location, damage can occur in November and December from new generation larvae or the following May when overwintered larvae are rapidly developing and devouring plant foliage.
- Description of Stages: These flies have a complete life cycle.
Eggs: Shiny black, 3/64-inch (1 mm) long, elongate-oval eggs with one side flattened and the other end pointed, are laid in turf.
Larvae: The eggs hatch into maggots which are white and worm-like. As these larvae grow, they molt into gray to grayish-brown larvae which develop a tough skin and are commonly called "leather jackets." The larvae have found instars and at maturity they may exceed 1.0-inch (25mm) in length. The head capsule may be exposed during feeding or moving but is often withdrawn if disturbed. The larvae have two typical spiracular plates (breathing holes) at the end of the anal segment. These plates are surrounded by six fleshy anal lobes.
Pupae: The translucent, brownish pupae have the legs, wind pads and antennae glued down and are first present just below the soil surface. These one-inch long (25mm) pupae wiggle to the surface at emergence time.
Adults: These large crane flies have a 13/16-inch (20mm) long, slender body with very long legs, almost 4-inches (10cm) from the front to back leg. Adults are brownish-tan with smokey-brown wings.
- Life Cycle and Habits: The European and marsh crane flies seem to require mild, winter temperatures, cool summers and average annual rainfall of at least 24 inches. Adult flies, which look like giant mosquitoes, emerge from lawns, pastures and roadsides in mid- to late spring and again in August to mid-September, depending on the species. The adults may gather in large numbers on the sides of hones and other structures. These adults, however, cannot bite or sting. The adults mate and females begin to lay eggs within 24 hours after emerging. The eggs swell in a few days by absorbing soil moisture. The European crane fly has one generation per season with the adults flying in late August into early October. The marsh crane fly often has two generations, one with adults emerging in late April through May and the second generation of adults emerging in mid-September into early October. Depending on the geographic location and the dominant species present, leatherjacket damage to turf can occur in November and early December or in the spring, usually May. Occasionally, large populations of nearly mature larvae can also cause damage in September, just before pupation and adult emergence. The eggs hatch in about two weeks into small, brownish maggots which begin feeding by using their rasping mouthparts on plant roots, rhizomes and foliage. By winter, fall emerging larva have molted twice and reached the third instar. This instar feeds slowly during winter temperatures but the fourth instar is reached in April and May. Turf damage can be evident in March, April and May. If European leather jackets, the larvae stay underground during the day but come to the surface to feed on damp, warm nights. Feeding damage usually stops by late May into June. The larvae then rest in the upper soil and molt into the pupal stage in late July into mid-September. The pupae remain just below the soil surface for 11 to 12 days in August. When ready to emerge, the pupae wriggle to the surface of the turf, from late August through September. Fall emerging marsh crane fly larvae feed in the fall and again in the spring, then pupate by early May. The spring adults lay more eggs and these larvae mature by late August and early September giving rise to new adults in September and October.
- Control Approaches: Controls are usually targeted against the young larvae before damage is evident. Regular monitoring of the turf in October and November should determine if controls are necessary.
Cultural Control - Habitat Modifications - Crane fly eggs and first instar larvae are very susceptible to desiccation. Refrain from watering turf in September. Ryegrasses seem to be less preferred as a food host.
Biological Control - Parasitic Nematodes - The commercially available nematode, Steinernema carpocapsae, has been effective when used at the rate of 22.2 billion infective larvae per acre. Other strains or species are being developed.
Chemical Control - Insecticide Applications - Good control has been obtained by applying insecticide sprays to infested turf in late October or in the spring, between April 1 to April 15.
Close inspection of the turf thatch zone should reveal the crane fly larvae. Soap solution flushes also bring up crane fly larvae but the larvae may be difficult to see in high-cut turf.