SHEPerspective: Crane fly

|  December 15, 2015

The green, green grass of home.

  • Sometimes turf pests become household pests.
  • European crane flies have begun to colonize North American turf.

Most homeowners love their lawns. They spend an incredible amount of time and energy maintaining them. From an ecological viewpoint, however, turf represents a large expanse of a single type of plant and is properly termed a monoculture. It also represents a treasure trove of food for insects and other organisms that live on grass, and can easily give rise to large populations of said organisms.

Many homeowners have already spent a small fortune cultivating their lawns and are quite prepared to defend them from all comers. Others don’t much care, as long as all the vegetation is green and roughly the same shape and height. But when the turf insects start building up on or in the house, both groups are ready to do battle.

Many insects and other arthropods emerge from grass to become household pests. One such species is the crane fly — large, gangly insects that look like mosquitoes. A scene in the movie Jurassic Park visually references a mosquito that is, in fact, a crane fly.

When I was young, we called these flies mosquito hawks because we thought they ate mosquitoes. As it turns out, however, they eat nothing at all as adults. They are members of a primitive family of flies Tipulidae (Ti-PEW-lid-dee), and feature vestigial, nonworking mouthparts as adults.

As you might suspect, working mouthparts are an important part of a long adult life, but these insects spend the majority of their lives as immatures. They carry all the energy reserves they will need to mate and lay the eggs that will become the next generation.

While we have many native species of crane flies, there are several introduced species that appear in lawns and turf throughout Canada and many parts of the northern United States. Known by such common names as leather jackets and European crane flies, they appear in the spring and fall as adults, sometimes in large numbers.

There are several explanations for the term leather jackets, but all have to do with the immature stages. Some sources report the larval skin is tough and durable like a leather jacket. Other sources suggest the shed pupal skins that appear in the grass resemble tiny leather jackets. Regardless, when the adults appear, they often show up on or in homes.

Trying to control the adults is often a waste of time and energy. Most of the effort should be focused on the turf. The best way to control crane flies is to target the larval stage and treat during the spring or fall when the larvae are feeding. By the time people see the large adults settling on objects around the house, the window of opportunity might have already passed.

There are many products on the market today that will be effective if the application is timed properly. Know your way around turf pest management before attempting to eliminate a turf pest. Just as it is important to read and follow the label for any product you use, know the state regulations regarding turf and ornamental treatments, and obtain the proper certifications before beginning.

You can reach Mark Sheperdigian, BCE, at shep@rosepest.com.

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