I received several calls earlier this week from golf course superintendents on the eastern end of Cape Cod, reporting that invasive cranefly larvae were active on many parts of the golf course. In past years we have received adult specimens from the Cape and the Islands, all of which turned out to be Tipula oleraceae, which is an invasive species that probably has been present in the southeastern part of the state for several years. It is sometimes called the “common cranefly” or the “marsh cranefly”.
The “common” cranefly often experiences two generations per year, with the first generation laying eggs in late April or early May, and larvae (large olive green, legless maggots with some noticeable projections on the tip of the abdomen) feed through the summer months. Adults fly in late August or early September, lay eggs, and the emerging larvae (of the second generation) feed through the fall. According to Dr. Gwen Stahnke (Washington State University), they can be active any time the ground is not frozen. Larvae will resume active feeding as the frost leaves the ground in late winter and can cause additional damage before pupating in April and completing their development.
The other species of invasive cranefly, the European cranefly (T. paludosa), has not yet been confirmed in Massachusetts. It has similar behaviors but completes only one generation each year (egg laying in September, larvae feeding in fall and again in spring, and then spending the summer in a dormant larvae phase before pupating in late August).
Both species of craneflies thrive when soil moisture levels are very high, especially at the time of egg-laying. Given that the adults were laying eggs in late August and early September, coinciding with the time when Hurricane Irene moved through the area, I believe the heavy rains provided favorable conditions for large numbers of larvae to survive. Meanwhile the unseasonably mild temperatures that have dominated the area over the past two weeks no doubt has enabled the larvae to forage for new food sources.
According to Dr. Stahnke, turf managers in the Pacific Northwest can achieve reasonable “knockdown” of larval populations with a pyrethroid such as bifenthrin. Turf managers in the Northwest do sometimes make applications in late November or December to reduce cranefly populations. Note that I have not conducted any field trials on craneflies, and so cannot speak from experience. If you feel you need to reduce the population, applications in New England should be delayed until air temperatures are at least in the high 40s, if possible. Also be sure that any pyrethroid application made at this time does not exceed the seasonal limit.
--
Submitted by: Dr. Pat Vittum
