Leatherjackets in Ontario - What Gives!

Table of Contents

1. How it all began
2. Description
3. Biology
4. Damage
5. Distribution
6. Monitoring
7. Control Options and Timing
8. References
9. Acknowledgements
10. Related Links

How it all began

The European crane fly, Tipula paludosa Meigen, is a pest in areas with a maritime climate in North America. This insect was first reported in Canada in 1955 on Cape Breton Island. The first reports from Western Canada were from Vancouver, B.C. in 1965 (Wilkinson & McCarthy, 1967). The larvae of this insect (leatherjacket) cause the most damage in turf and pasture grasses, but they have also been shown to cause some damage in fruit and vegetable crops. Its North American distribution was limited to the western and eastern Maritime provinces of Canada (British Columbia and Nova Scotia) and on the western coast of the United States (Washington State and Oregon). In 1996 and 1997 there were several reports of leatherjackets causing damage in turf from Whitby, Toronto and Hamilton mountain area. In 1998 they were identified as European crane fly (Tipula paludosa Meigen)

There is considerable information on the lifecycle of this insect for the maritime regions, however there was no information about the European cranefly in Southern Ontario. During the summer of 1999 and 2000, leatherjackets and crane flies were collected weekly in the Ancaster area to determine the lifecycle of this insect in Ontario. European crane flies were collected at two sites in Ancaster: Knollwood Golf Course and a home lawn. Samples were collected from mid-May to mid-Nov., 1999 and 2000. Larval length and weight were measured to determine the larval stages throughout the year. Adults were also observed and collected during the adult flight period and one egg mass was found during the sampling period in 1999. During the spring, samples were found by examining the turf at the soil surface. In June and July the larvae moved down 3-5 cm into the soil. During this period, samples were collected using a golf course cup changer. Adults were collected using a sweep net. The egg mass was collected using a golf course cup changer. Soil temperature at a 2.5cm and surface temperature were measured on each sampling day at each site.

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Description

European crane fly adults resemble a large mosquitoes (Figure 1). They range in length from 1.5-2.5cm and have a grayish brown body. The adult crane fly has two narrow wings and very long brown legs. Unlike mosquitoes, however, they do not sting or bite and are relatively weak flyers. Eggs are laid in the upper 2-4cm of the soil and are black and oval in shape and are roughly 0.1cm long. The larvae of the European crane fly are known as leatherjackets because of their thick skin. They are light grey or greenish brown with irregular black specks. Leatherjackets are cylindrical but taper slightly at both ends and are typically 3-4 cm at maturity (Figure 2a). The pupa is formed inside the last instar cuticle and is called a puparium. The pupae are brown and spiny and are 3.3 cm in length.

Figure 1. A European crane fly adult.
Photo courtesy of Bob Costello, British Columbia Ministry of Food and Fisheries.

Figure 2a. Leatherjacket larvae

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Biology

There is one generation of T. paludosa in Ontario. Fourth instar larvae were found feeding on the top of the soil in early May when sampling first began. They grow rapidly at this stage and typically reach their full length (3-4 cm) by mid-June. This is when the majority of the damage is noticeable. By the second week in June the larvae had stopped feeding and had moved down 3-5cm deep in the soil where they remain in a non-feeding stage throughout the summer until they pupated in late August. At this time, the pupae wiggle to the surface and adults emerge, usually after sunset and are at sexual maturity. They mate immediately and the females lay between 200-300 eggs within 24 hours of emerging. The males typically survive for 7 days, while females live for only 4-5 days. Adult flights lasted for two weeks from Sept. 21 to Oct. 4, 1999 and Sept. 6 to Sept. 27 in 2000. The eggs are laid on the soil surface or at depths of less than 1 cm. They require immediate moisture to survive and hatch 11-15 days later. Eggs of T. paludosa were found during the last week in September. Upon hatching, the larvae feed immediately throughout the fall and warm periods of the winter in the upper 3 cm of the soil. The first instar larvae were found in the first week in October and second instar larvae were found weekly from mid-October until the middle of November. Leatherjackets usually complete the first two instars within two months of hatching and winter as 3rd instars when their metabolism slows down. This pest thrives in mild winters, cool summers and rainfall averaging 600mm per year.

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Damage

The leatherjackets feed primarily on turf on home lawns, golf courses and sometimes pasture grasses. They feed during the day at or below the surface of the turf on root hairs, roots and crowns. On damp warm nights, they migrate to the surface of the turf and eat stems and grass blades (Figure 2b). Damage to turf in Ontario occurs during the month of May (Figure 3). The peak damage was in early May in 1998 and in late May in 1999. Damage can occur on golf greens from birds pecking out the leatherjackets from the greens during the month of May (Figure 4).

Figure 2b: Leatherjacket larvae at surface of turf

Figure 3. Some typical leatherjacket damage on a home lawn.

Figure 4. Damage on golf course from birds pecking at larvae.

Distribution

A survey conducted in 1998 and an informal survey in 1999 and 2000. This revealed that the main areas of infestation were Ancaster, Niagara Falls, Hamilton mountain, Scarborough, Uxbridge, Oshawa/Whitby , Brampton, Markham, Kitchener/Waterloo and Guelph. Currently in the spring of 2002, the following new areas have reported leatherjacket infestations: Windsor, Cambridge and St. Catharines.

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Monitoring

Adults

There are several different methods for monitoring for adult European crane flies. The first such method is sweep net sampling. This method is the least effective, as the adults appear to have the ability to avoid the sweep nets. The next method that has been investigated is sticky cards. Tests with this method indicated that it is effective in areas of high abundance. There was also a risk of the cards being destroyed by various vertebrates and environmental factors. The use of light to attract the flying adults at night was found to be somewhat useful as well. The most effective method of monitoring for adult European crane flies was timed visual counts while walking. A one minute timed count was conducted while slowly walking though the trial area. It was observed that certain areas resulted in different numbers of adults indicating that there may be optimal places to use this method and that it should be conducted numerous times to determine these areas.

Pupae

The contributions that monitoring for pupae in relation to assessing an adult crane fly population is still being determined. This practice has more application in short cut turf. Here, the pupae can be more easily seen as they wiggle to the surface for counting. It is also possible to utilize crows foraging as scouts to pinpoint areas with high pupae populations.

Larvae

An effective way to evaluate the population of larvae in turf is to remove a section of sod 15cm by 15cm, which is 2.5-5cm deep in early spring. Submerge it in a saturated salt solution (dissolve enough salt in 3-4 litres of water to float an average size potato) and wait 5 min before counting. If more than five larvae float in the solution, apply an appropriate insecticide. Conversely, you can simply cut away three sides of a 30cm square, 7.5cm deep and fold the section back. Scrape the soil from the roots and count the leatherjackets before firmly placing the grass back into place and watering. If more than 25 larvae are observed in this section, you can expect damage. If the grass is unhealthy to begin with, the threshold will be closer to 15 larvae per section. Also, an insecticide drench can be applied to a section. This will force the larvae to the surface for easy counting. Warm winters and early springs can awaken leatherjackets from their weak hibernation, which results in early feeding and subsequently early damage. If the winter has been warm, watch carefully for damage, particularly if there has been a history of infestation. Furthermore, if a large number of adults were identified in late summer, this could indicate that there will be an infestation of larvae in the spring.

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Control Options and Timing

Thresholds for leatherjackets are between 15-25 per 0.1m2 of turf depending on the overall health of the turf with the lower threshold of 15 for turf that is in poor condition to start with . There are two products registered for use on leatherjackets on golf courses: Dursban and Sevin T&O, As of November, 2006, Sevin T&O can be used to control leatherjackets on all turf, including home lawns. Read the label carefully because some restrictions apply. Rates for these products can be found in OMAFRA Publication 384, Turfgrass Management Recommendations. Insecticide applications for leatherjackets can be made in October before the soil freezes up when the larvae are feeding close to the surface, are small and have not caused significant damage yet. If preventative applications are applied in the fall, further applications in the spring may not be necessary. However, applications can be made in the spring when damage from feeding first starts to appear. Insecticide spray against adults are typically ineffective as the adults do not feed and mate and lay eggs shortly after emerging. There are several cultural methods to controlling leatherjackets as well. Firstly, the eggs are sensitive to soil moisture and the larvae strive in moist conditions, therefore the drainage of areas with chronic problems should be checked and possibly improved. Furthermore, avoid irrigating dry turf in the fall if an infestation is predicted. Maintaining vigorous turf growth with proper fertilizer levels and soil pH may ward off severe damage. If an infestation is occurring, raking the larvae up at night when they come to the surface to feed and submerging them in soapy water may alleviate the problems.

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References

Wilkinson, A. T. and H.R. MacCarthy. 1967. The marsh crane fly, Tipula paludosa Mg., a new pest in British Columbia (Diptera:Tipulidae). J. Entomol. Soc. Brit. Columbia. 64: 29-34

Gelhaus, Jon K. The Introduced European Crane Fly and the Marsh Crane Fly: Two species with potential to damage Turf grass, Cereal Crops and Nursery stock in the Northeast U.S.

Macdonald, S. 1995 Managing leatherjackets on home lawns. http://www.gov.ns.ca/nsaf/elibrary/archive/hort/lawn/leatherj.htm

Antonelli, Arthur L. and G. Stahnke. 1998. European Crane Fly: A lawn and pasture pest. http://cru.cahe.wsu.edu/CEPublications/eb0856/eb0856.html

Jackson, D.M. and R. Lee Campbell. 1975. Biology of the European Crane Fly, Tipula paludosa Meigen, in Western Washington (Tipulidae; Diptera). Washington State University Technical Bulletin. 2-18.

Natural Resources Canada - Canadian Forest Service. European marsh crane fly (leatherjackets). http://www.pfc.cfs.nrcan.gc.ca/diseases/nursery/pests/european%5Fe.html

Henderson, D. and M. Dogterom. 2002. Using Nematodes for Biocontrol of Soil Pests. Western Canada Turfgrass Association Research Page. 32-35.

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Acknowledgements

• Jim Harris and the staff at Knollwood Golf Course for allowing us to sample weekly throughout the growing season and for supplying us with a golf cart each week.
• Rick Fountain of Hired Hands, Ancaster for finding us a home lawn site for collection of crane flies.
• All respondents for the 1998 European Crane Fly survey.

Related Link

• European Crane Fly: A lawn and pasture pest
• Natural Resources Canada - Canadian Forest Service. European marsh crane fly (leatherjackets)

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