Bt references

[Semjase]

>I can confirm that Mourning Cloaks do use elm trees.  I have found
>colonies of mourning cloak larvae on elms planted along a road in Reno,
>Nevada. I have also raised mourning cloak larvae on cut elm branches.
>
>However, I do not agree with Semjase that spraying Bt could drastically
>reduce mourning cloak butterfly populations. If there was such a thing
>as a formulation of Bt was that effective against any common and nearly
>cosmopolitan species of lepidoptera, the company that made it would be
>wealthy beyond belief.
>
>As a side note, the mourning cloak is one of our most successful urban
>butterflies. For example, it is a frequent sight in Los Angeles and
>Mexico City.
>
>Paul Cherubini, El Dorado, California
>paulcher at concentric.net
>
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I wonder how in the world he could have missed the most common food plant. 

Anyhow they were spraying because of the cloaks, dutch elm disease is most
common in the midwest and is devastating the American Elm populations.  Another
case of a "natural" thing out of hand.  "Natural" does not mean safe.  

I wish to point out that they were spraying because of the cloaks because
people didn't like the droppings of the caterpillaes.  Once a population is
seriously depleted it may not return for a long time.  In addition I fail to
see anyone actually proving that it does not persist and grow in the soil
thereby acting as a continual cause of infection of the population.

S.