Cool spring weather is ideal for crane flies. Many species of these long-legged mosquito-like flies live in Kentucky. They come in many sizes and resemble their close relatives: mosquitoes (Figure 1). Crane flies do not have the long sucking mouthparts of mosquitoes. In fact, their dietary intake is probably not much more than nibbling on water droplets for moisture. They only live a few days, dying soon after mating and laying eggs.
Crane flies are most abundant near shady areas with decaying organic matter where their larvae feed on accumulations of wet leaves, on excess grass thatch, or near streams and rivers. The larvae also can thrive in areas that are over-watered or where excessive rainfall has left soils moist for long periods.
Crane fly larvae are light gray-brown legless worms with soft bodies and no distinct head; they have small finger-like projections from the tail (Figure 2). Many wriggle through moist decaying matter to feed; others live in streams. Many spend winter as partly grown larvae and finish their feeding and development in March or April.
Crane flies pose no threat to humans or pets and will soon disappear, so there is no need for control. An abundance of crane flies in spring and fall can mean there is a water management issue that could be corrected. Water management problems can include excessive irrigation of turf, poor soil drainage, or accumulations of excess thatch. These situations could also lead to turf problems, or in some cases they can become breeding sites for gnats that do bite.
By Lee Townsend, Extension Entomologist