Ideas needed for propigation with Cran Fly infestation

I live in Washington (Eastern) State where we are having a problem with Crane Flies. http://cru.cahe.wsu.edu/CEPublications/eb0856/eb0856.html

Everything that I plant is eaten up before it gets over an inch high. I've been collecting small yogurt containers all year to use as collars on my plants but know I will also have to use strips of cardboard to set them in. I used that method last year. I had to replant things 3 times and eventually sewed my seeds in flats and transplanted them after they had grown a bit taller. Beans, carrots, beets, cucumbers, melons, mainly seemed to be what they liked.

Last fall the amount of flies seemed to be reduced allot, so I'm hoping our chickens have been eating them and decreasing the population of CF significantly.

I'm wondering if any of you have any other ideas as to how to deal with them. Such as nifty collars or barriers to keeping them out? Or any other imaginative ideas.

Thanks for any ideas you could give me.
Sagewood Farm

I do not know these flies. I have had a problem with fungus gnats in the past, used black flag flying insect spray to kill the adult flies. It will not harm your plants if it gets on them. Then used hydrogen peroxide 2 tablespoons per quart and lightly sprayed to top of the soil to kill the eggs and larvea. It wouldn't hurt your plants to give this a try, it really helped mine.
Rebeccanne

Wood ashes can be used at the bases of plants to repel flies from laying eggs in soil near plants. I imagine their must be some form of Bacillus thurigensis that can be used on the soil surface to kill the larvae. These organic gardening methods.