EUROPEAN CRANE FLY -
MANAGEMENT HISTORY AND LOSS OF DURSBAN -
WHAT DO WE DO NOW?
L. Antonelli, Ph.D.
K. Stahnke, Ph.D.
The European Crane Fly (Tipula paludosa Meigen) was first found on this continent in Newfoundland in 1952 (Fox, D.J.S. 1957). It made it's appearance on the West Coast in Vancouver, B.C. in 1965 where larvae were causing severe damage to lawns (Wilkinson, 1969). They were first detected in Washington State in 1966 (Jackson and Campbell, 1975). While largely restricted to western Washington, they have been found on a few occasions in Spokane County and Yakima County. By 1989, it had made its debut in western Oregon (Williams et al., 1989) and testimonials from California farm advisors suggests its presence in their state about five years later.
There are several accounts of the European Crane Fly life cycle, but none so thorough as that by Jackson and Campbell, 1975. Adult crane flies emerge from the soil of lawns, pastures, and other grass areas from late August to mid-September. This can vary at both extremes depending on the year. The females mate and lay eggs in grass within 24 hours after emerging. These eggs hatch into small, gray-brown, wormlike larvae, which develop a tough skin; they are commonly called "leatherjackets". The leatherjackets feed on the roots and crowns of clover and grass during the fall. They winter in the leatherjacket stage. As the weather warms in the spring, they continue to feed. Damage by their feeding may become especially noticeable in March and April. During the day, leatherjackets mostly stay underground, but on damp, warm nights they come to the surface to feed on the aboveground parts of many plants. Leatherjacket feeding stops about mid-May. Leatherjackets go into a nonfeeding stage just below the soil surface during July and August. From late August through September pupae wriggle to the surface and the adult crane flies emerge (Antonelli and Stahnke, 1998).
It's important to point out that two years ago a second turf damaging crane fly made its appearance in the Northwest. This crane fly is called the common crane fly (Tipula oleracea L.) and is extremely similar in appearance to the European Crane Fly. In fact, the larvae are nearly impossible to separate (LaGasa and Antonelli, 2000). The adults, however, can be distinguished with certain eye feature differences. The arrival of the common crane fly complicates current management recommendations inasmuch as there are two generations per year where European Crane Fly has but one.
Common crane fly has an early adult emergence in April and May as well as second emergence along with T. paludosa in August and September (LaGasa and Antonelli, 2000). We are currently assessing timing recommendations to deal with both species.
CURRENT MANAGEMENT PRACTICES
It has been recommended that crane flies be controlled between April 1 and 15 if larval populations exceed 25/ft2. This was a threshold set by Campbell in the 1970's. It can vary with the thriftiness of the lawn. Both authors have seen turf where numbers exceeded 40/ft2 with no apparent damage in well-maintained turf. Conversely, damage has been observed in unthrifty lawns with as few as 15/ft2 (Goss, R. pers. Com.).
The application dates mentioned above reflect "normal" years and, as such, are generalizations. There have been years when temperatures in December and January were unseasonably warm, and since European Crane Fly undergoes a weak hibernation, prolonged warm periods can awaken them. Such warm periods result in early feeding that leads to serious lawn damage at that time of year. Therefore, if warm winters occur, watch the lawn carefully for damage development, particularly if the area has had a history of crane fly problems.
Preventive fall applications (between October 1 and October 31) have been successful. This is the time when most of the eggs have hatched and the larvae are small and vulnerable. This application period is encouraged for turf/sod industries to prevent possible shipment of crane fly to uninfested areas, and for golf greens, which are extremely expensive to repair. If a fall application is made, application should not be needed the following spring (Antonelli and Stahnke, 1998). With the introduction of T. oleracea, fall applications may become more common, since such applications will surely eliminate both species.
Perhaps the weakest link in pest management for crane fly is monitoring. Four-inch diameter cup cutter cores are examined by manually pulling apart the contents. It is difficult to convince homeowners to do this before spraying. Hence many applications are preventive in nature. There have been many attempts in substituting a quicker method for core sampling. Gasoline was used by Jackson and Campbell, 1975. It had an irritating effect on the larvae such that they would exit the sod almost immediately. Orthodichlozobenzene had a similar effect (Barnes, 1941). These are impractical and environmentally damaging if not illegal, however. Dish soap solutions, insecticidal soaps, ammonia, and bleach as well as Dursban solutions have been tried and none except Dursban produce even near 50% of true populations that manual examination of cores demonstrate (Stahnke and Antonelli, 1995).
While cultural and biological techniques have been tried, chemical controls, when effective, have the most pronounced effect. It has been observed that properly fertilized lawns can endure huge numbers of larvae and without visible damage. Indeed Blackshaw and Newbold, 1987, showed that N fertilizer treatment in the U.K. during the third week of March produced grass yields nearly equal to those where Dursban was used alone. There have been attempts to identify grass cultivars that demonstrate some level of host plant resistance (Pesho et al., 1981). This kind of work has not been fruitful to date.
Various biological methods
have been utilized. In Canada during 1968, a tachinid parasite Siphona
geniculata (de Geer) was released and concurrently an iridescent
virus was also tested. Neither has been particularly successful
(Wilkinson, 1969). Nematodes show some efficacy, but rarely demonstrate
more than 50% reduction in larval numbers (Stahnke and Antonelli,
Chemicals have historically been the major management tool for crane fly control, but with the impending loss of the most effective chemical, Dursban, we are faced with a formidable challenge in finding a replacement that is both effective and reasonably environmentally sound. The table below provides a picture of past failures and successes in the PNW. It is apparent that successes that are reasonably safe have been limited (Stahnke et al., 1993 Campbell, 1975, Goss et al., 1986). The ratings are based on interpretation of data based on larval reduction from pretreatment spring sampling and data comparing treatments and checks from post treatment spring sampling.
Antonelli, A.L. and G. Stahnke.1998. European Crane Fly: A Lawn and Pasture Pest. . WSU-CES: EB 0856. 4 pp.
Barnes, H.F. 1941. Sampling for Leatherjackets with Orthodichlorobenzene Emulsion. Ann. Appl. Biol. 28:23-28.
Blackshaw, R.P. and J.W. Newbold. 1987. Studies on the estimation of Sampling Error for Leatherjackets (Tipula spp.) in Grassland. Grass and Forage Science 42:347-351.
Campbell, R.L. 1975 Insecticidal
Control of European Carne Fly in Washington. J. Econ. Ent. Vol.
68, No. 3. pp 386-388.
Jackson, D.M. and R.L. Campbell. 1975. Biology of the European Crane Fly, Tipula paludosa Meigen, in Western Washington (Tipulidae: Diptera). W.S.U. Tech. Bull. 81. 23 pp.
LaGasa, E.H. and A.L. Antonelli. 1999 Western Washington Tipula oleraceae Survey (Diptera: Tipulidae) 2000. WSDA PUB 034 (N/1/00). 8 pp.
Pesho, G.R., S.E. Brauen, and R.L. Goss. 1981. European Crane Fly: Larval Infestations in Grass Cultivars. Journ. Econ. Ent. pp 230-233.
Stahnke, G.K., S.E. Brauen, A.L. Antonelli, and R.L. Goss. 1993. Alternatives for European Cranefly Control in Turfgrass. International Turfgrass Soc. Res. Journ. 7. R.N. Carrow, N.E. Christians, R.C. Shearman (Eds.). Intertec Publ. Corp. Overland Park, Kansas. pp 375-381.
Stahnke, G.K. and A.L. Antonelli. 1995. European Crane Flies in the Pacific Northwest. Golf Course Management. December. pp 56-60.
Wilkinson, A.T.S. 1969. Leatherjackets - A New Pest in British Columbia. Canada Agriculture.
Williams, J., R.C. Eickelbarger,
and G.C. Fisher. 1989. The European Crane Fly: A Serious Pasture
Pest in Tillamook County. OSU-EM 8411. 4 pp.
Arthur L. Antonelli,
Gwen K. Stahnke, Ph.D.
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