The Ohio State University

Home TurfNotes I received an email from John Cummings in West Virgina who sent photographs of those good old crane fly larvae. Decaying organic matter is highly attractive to several insects that normally help us dispose of this tough-to-digest cellulose. The larvae of crane flies and March flies are especially adept at finding this moist plant material and each can develop rather large populations. Now, and over the next few weeks I suspect that I will receive inquiries from West Virgina (already) Kentucky, Ohio, Pennsylvania and New York about crane fly and March fly maggots.

What can make things worse is that some professional turf managers (golf course superintendents and lawn care specialists) have heard about the problems associated with the European species of crane flies which have been a major pest problem in the Pacific Northwest. The European species actually feed on grass plant leaves and large populations can destroy well maintained turf. Unfortunately, these species were also detected in the Toronto, Canada area in the 1990's and these have now moved into the Buffalo, New York region (photograph to the left). However, surveys in Ohio and surrounding states have not yet detected these foreign invaders, so any crane fly larvae found are most likely native species.

We have several dozen native crane fly species that commonly infest turf that has been killed by white grubs, billbugs, disease, or inundation by water (wet sites). Like the European species, we have spring-flying and fall-flying species, so killed turf can be infested at either time. Fall-emerging species lay eggs in October that hatch within a week or two. The tan larvae hatch and feed during the fall until the ground becomes frozen. These larvae finish their development in the spring often attaining a length of slightly more than one inch. By June, these mature larvae dig into the soil when the weather turns hotter and dryer. These larvae hang out until the fall, at which time, they pupate and emerge as adults. Spring-emerging species lay eggs in late April through May. Their larvae feed into June and may continue feeding during cool and wet summers or they go into a summer dormancy until the fall rains return. They then finish most of their feeding by the time that the soil freezes. In March and early April, these larvae pupate.

So, it's not uncommon to find lots of crane fly larvae (often called leather jackets because of their tough but flexible exoskeletons) within or under dead turf that remains in the spring. They are not the cause of this dead turf, but are taking advantage of the food.

March fly larvae are much smaller than crane fly larvae, but these larvae also feed on decaying plant material. You can often find dozens of them balled together under patches of dead turf. These flies emerge in May and early June in Ohio. (Okay, they emerge in March in Texas! I saw them flying last week!) The adults commonly lay eggs under cow paddies, under piles of grass clippings, or in thatchy turf. While the larvae generally feed on this decaying plant material during cool and wet periods of the year, there is a fair amount of evidence that the larvae may actually damage living grass stems and roots when they run out of decaying organic matter.

Bottom line, I wouldn't be overly concerned if you find quite a few of either of these maggots, especially in turf that was killed last year from billbugs, grubs or drought. However, I would still like to hear from you if you see a lot crane fly larvae as we remain on the outlook for the potential that some of the European species could be transported into Ohio.

If you feel that you must get rid of these fly larvae (they can cause problems if you are reseeding an area), an application of one of the pyrethroids should do the trick. In addition, Arena® and Meridian® are very effective against these maggots and early applications (in late April and early May) will eliminate these pests and should also provide sufficient residual to knock out the black turfgrass ataenius and annual grubs that arrive in July, such as masked chafers and Japanese beetles.

Posted by David Shetlar