Mosquito Hawk or Crane Fly?
I caught this "sucker" in my living room last night. My mother-in-law was shouting that a giant mosquito was attacking her.
That's a common misconception about the European Crane Fly.
Tipula paludosa, which is also called "Mosquito hawk", "daddy longlegs", or "leatherjacket", is a flying insect native to Europe but was first reported in Canada in 1955.
An adult crane fly looks a lot like an oversized mosquito with its slender body, transparent wings, and stilt-like legs. That's where the similarity ends. The wingspan of these giants can be up to 6.5 cm! Unlike mosquitoes, crane flies do not bite people or animals. In fact, crane flies occasionally drink nectar. The reason we fear these insects is not because of the big flying adult.
In August and September, the adults emerge from their underground hiding places to mate and reproduce. They will lay their eggs within the top 1 cm layer of a turf surfcae. One female can lay up to 300 eggs! Two weeks later, the larvae hatch and begin to feed on the grass. However, the majority of the damage to the grass will happen next spring.
Larvae (also called leatherjackets) feed during the day on roots and crowns of turfgrass. On damp warm nights, they come up to the surface to eat stems and grass blades. Damage usually occurs in May to June in Ontario, and appears as thinning to bare patches in a lawn. Animals such as skunks and starlings can also damage the turf in their hunt for a tasty leatherjacket snack.
What can we do?
The first thing is to maintain healthy turf through proper mowing and fertility.
Secondly, adult crane flies prefer to lay their eggs in moist soils. Improving drainage will help dry out soils and deter females from laying eggs. Newly hatched larvae also have poor survival in dry soils.
Chemical control products are available for golf courses and sod farms to prevent damge from leatherjackets. See OMAFRA Publication 384, Turfgrass Management Recommendations, for information on control products and rates.
For home lawns and other non-excepted uses, there are some control product containing beneficial nematodes. These applications should be made in the fall to reduce leatherjacket populations in Ontario.