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GARDENER'S
READING ROOM
Fertilizers,
Pest Control and Soil Management
Lawn Care
Organic Gardening
Cranefly
Control
 Don’t
panic! Controlling cranefly is not as difficult as you think!
Cranefly
is a word that strikes terror in the hearts of lawn owners—more
so now because of the coming demise of Diazinon and Dursban.
Quite frankly, this is an unfounded fear. First, cranefly
damage to healthy lawns is far less than thought. Secondly,
lawn chemicals have historically been tremendously OVERused.
So,
what are we to do to control cranefly in our lawns? First
we need to understand their life cycle. The adult emerges
summer to early fall, mates, and lays eggs. The eggs hatch
in fall and begin feeding. As winter approaches the larvae
go dormant. As spring temperatures warm, the larvae begin
to feed again in the top 1-2" of soil and thatch. By
late spring the larvae begin to pupate and the cycle repeats
itself.
Damage
usually appears after the larvae have stopped feeding, so
it’s important to monitor populations in early spring.
Either spade a 1-2’ square to a depth of 2-3" or
mix 1 ounce biodegradable soap with 1 gallon warm water, pour
it out over 1-2 square feet, and wait 15 minutes for larvae
to surface. Damaging levels are 15-25 per square foot. Healthy
lawns are normally unharmed by lower levels.
The
first and best defense against craneflies, therefore, is a
healthy lawn. Apply good organic fertilizer 3-4 times per
year and lime at least yearly. Use a mulching mower, removing
no more than 1 /4 to 1/3 of the grass blade at one time. Water
infrequently but deeply (1" per week). Finally, rebuild
your soil’s natural soil microorganisms to help keep
damaging insects (and diseases) in check. Organica makes a
product specifically for turf areas called Microbial Soil
Conditioner™. If the cranefly population is at damaging
levels, the product Scanmask™ will inoculate your soil
with beneficial nematodes that parasitize cranefly larvae.
Lastly, encourage birds in your yard. Robins and yes, starlings
and crows, are voracious eaters of cranefly larvae.
If
you do ever encounter a problem you can’t deal with without
chemicals, there should soon be new products coming to replace
Dursban and Diazinon. Remember, if you use a chemical control,
you will need to reestablish beneficial microorganisms once
the residual life of that chemical is over.
In
summary, cranefly is not as devastating as generally thought.
Using good organic lawn practices will go a long way towards
controlling their population and minimizing their damage.
By Charlie Shull, W.C.N.
Skylights Winter/Spring 2001, Vol 15, No. 1
Other
articles on fertilizers, pest control and soil
management
Other
articles on lawn care
Other
articles on organic gardening
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