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Sampling Crane Flies 

Here are some simple guidelines for monitoring crane fly populations, all you need is a cutting utensil, ruler and a handlens.

What To Sample:crane fly larva

Larvae, or leatherjackets, are the damaging stage of the crane fly's life cycle. You will be looking for grub-like tubular worms. These larvae come in many different sizes depending on the time of year you sample for them.

When To Sample:

Sampling can begin as early as January, however during some years the larvae are small and difficult to see. In February and March, larvae increase in size and become more apparent.

Where to Sample:damaged area

Select four areas in your lawn, these can be randomly made or you can look for suspicious signs of damage. If you choose to look at damaged areas, sample on the margins of the damage; don't sample bare ground. Another good clue for finding suspicious areas to sample, look for birds, especially robins, starlings, and gulls. Many times I have found crane flies by looking for holes punched through the grass by bird beaks. Birds are excellent crane fly scouts.

How to Sample:
cutting a sample
Once you've located your site, get your handy ruler out and measure a six inch by six inch square.

Using a knife or cutting implement (I prefer using a butter knife so I don't stab myself by accident), score the area by cutting into the ground about 3 inches deep (just deep enough to cut through the dense root mass).
larva in root zone
Pull back the turf sample. Grass is usually tough and will hold together.
First inspect the hole in the turf for any larvae. Sometimes they are feeding in the zone where the roots pull away from the soil, these larvae will spill out as you pull up the sample.
Then inspect the edges of your sample; many times you will cut into the larva. If you do this enough, you will become an expert on how to determine the difference between sliced earthworms and leatherjackets.
break up the sample
Begin to break up the sample; many times the clod will tear along areas where there are crane flies. Look for larvae in the thatch layer of the turf, this is where most larvae prefer to hang out and feed, about ½ inch deep.

Count all the larvae you've seen. larvas size
Multiple this number by 4 to determine the number of crane flies per square foot of lawn.
Replant your sample back into the divot that was created. Turf is hardy and will reestablish with no problems and it will become unnoticeable shortly.

Repeat this three more times to find the average number of crane flies per square foot of lawn.

Now that you have a good idea how many crane flies you have in your lawn, read on and make an educatued decision about what to do.
In this article...


Crane Fly Sampling


Treatment Options

See also:

Crane Fly Identification

Native Crane Fly Identification

Crane Fly Calendar

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