Distribution. The origin of European crane fly or "leatherjacket" is northern Europe, where it occurs from Finland to Great Britain. It was first found in North America in Labrador during 1952, followed by Nova Scotia in 1954, and British Columbia in 1965. The eastern populations have not expanded greatly, but on the west coast the population quickly spread south and east from Vancouver into western Washington and northwestern Oregon.
Host Plants. Larvae feed on numerous plants, though they are generally considered to be pests of pasture and turf grasses. Among vegetables attacked are beet, cabbage, cauliflower, corn, lettuce, pea, potato, rutabaga, turnip and likely others. Other crops such as barley, buckwheat, clover, flax, oat, rape, strawberry, tobacco, and wheat are also reported to be damaged occasionally, and various weeds are eaten. They can persist, but do not thrive, on decaying organic matter.
Natural Enemies. Probably the most important natural enemy of European crane fly in North America is the larval parasitoid Siphona geniculata (De Geer) (Diptera: Tachinidae), which was introduced from Europe. Several pathogens were identified in Europe or North America, including viruses, fungi, and protozoans, but they occur infrequently (Jackson and Campbell, 1975). Moles and birds are frequently cited as predators of leatherjackets, though there is no evidence that they can suppress populations. Weather seems to be more important than natural enemies, with survival or damage favored by cool, wet conditions in the spring and moist conditions in the summer, but negatively affected by cold winters.
Life Cycle and Description. There is a single generation annually, with this insect overwintering in the third instar. Larvae typically become fourth instars in April, pupate in August and then in rapid succession the adults emerge, eggs are deposited, and larvae begin to grow in September. The first two instars are completed by November, when larval growth slows for the winter.
European crane fly larva.
The adults are fairly small, the males measuring about 14-19 mm long, the females about 19-25 mm. They are narrow-bodied, brownish, with very long legs. Emerging females are incapable of flight, but after depositing most of her eggs they can disperse by flying. Females deposit about 200-300 eggs, nearly all on the night of emergence as an adult. However, adult females can persist for 4-5 days, and males survive even longer, often 7 days.
The biology of European crane fly in North America was described by Jackson and Campbell (1975) and Wilkinson and MacCarthy (1967). Useful publications describing this insect in England include those by Rennie (1917) and Coulson (1962). Barnes (1937b) described crane fly culture. Keys to crane fly genera, including both larval and adult forms, were presented by Alexander and Byers (1981).
Surprisingly, the larvae feed not only below-ground on the roots and plant crowns, but also climb the foliage at night and attack the leaves and stems. When larvae are numerous, plants may be killed.
Cultural Practices. Tillage can be very disruptive to overwintering larvae, though it rarely eliminates all leatherjackets. Flooding is more detrimental to larvae, but more difficult to accomplish. Dry soil is not attractive to ovipositing females.
Biological Control. The nematodes Steinernema bibionis and S. carpocapsae (both Nematoda: Steinerne-matidae), have been shown experimentally to infect larvae of European crane fly (Poinar, 1979), but apparently these potential biological control agents have not been evaluated under field conditions.
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