Larval feeding by crane fly leatherjackets causes visible damage such as brown patches or spots in grasslands, turf, and cereal fields. The larvae create burrows in the soil, and exit holes from these tunnels may also be seen on the surface. In addition to direct feeding damage, secondary harm often occurs when birds, rodents, and other animals dig into the soil to feed on the larvae, further disturbing and damaging the turf.

Adult crane flies are large insects, with females reaching a wingspan of 45 to 50 mm. They have long, slender legs and one pair of narrow, clear wings marked with distinct veins. The eggs are black, oval-shaped, about 1 mm long, and are laid on the soil surface. The larvae are cylindrical, tapering toward the head, and grey-brown in colour. They develop through four larval stages (instars) and grow up to 2.5 cm in length when fully mature. Pupae are greyish-brown, also about 2.5 cm long, and after adult emergence, part of the pupal case may be visible protruding above the soil surface.

Adult common crane flies emerge from the soil from late summer through fall. After mating, females lay between 200 and 300 eggs on the soil. The larvae hatch within about one week and begin feeding on the roots and crowns of grasses during autumn. These larvae overwinter in the soil, usually in their third instar stage, and resume feeding in spring as the soil warms. Larvae become especially active and voracious during this time. Pupation occurs below the soil surface in summer, lasting approximately two weeks before the next generation of adults emerges to continue the cycle.

Preventing crane fly infestations can be difficult, especially in areas where the pest is already well established. Even if a lawn or field is carefully managed, nearby untreated areas—such as neighbouring yards, pastures, or green spaces—can serve as sources of re-infestation. Adult crane flies are strong fliers and can easily travel to new areas to lay eggs, meaning that well-maintained turf may still become infested from external populations. Additionally, because the larvae live hidden in the soil and the adults are short-lived and active mainly at dusk or night, infestations often go unnoticed until significant damage is already present.

Effective prevention requires an integrated approach, including good lawn care practices such as regular mowing, aeration, and proper irrigation to promote strong root systems that can better tolerate feeding. Monitoring for adult crane fly activity in late summer and fall can help time interventions, and applying biological controls—such as entomopathogenic nematodes—when larvae are small can reduce populations. However, as with European chafer, complete eradication is unlikely, and yearly monitoring and management are necessary to keep damage to a minimum. Community-wide awareness and coordinated action are key to reducing long-term crane fly pressure.

Capsanem is a biological control product that contains the beneficial nematode Steinernema carpocapsae, which is effective against crane fly larvae (leatherjackets) in turf and other grassy areas. These microscopic nematodes actively search for larvae in the soil and enter their bodies through natural openings. Once inside, they release symbiotic bacteria that quickly kill the host. The nematodes then reproduce inside the dead larvae and move through the soil to find new hosts, continuing the control process.

Capsanem is most effective when applied in the fall, shortly after adult crane flies have laid their eggs and the newly hatched larvae are small and feeding near the surface. A second application in early spring, when soil temperatures begin to rise and the larvae become active again, can further reduce populations and limit damage. For optimal results, the soil should be moist at the time of application, and irrigation before and after treatment is recommended to help the nematodes move through the soil and find the larvae.

Used as part of an annual management program, Capsanem can significantly reduce crane fly larval populations and prevent extensive turf damage. While it does not guarantee complete eradication—especially if nearby areas are untreated—it is a safe, environmentally friendly, and effective tool when integrated with good lawn care and monitoring practices.