Interesting ...

Paul Cherubini monarch at
Tue Apr 16 18:02:10 EDT 2002

Mark Deering wrote:


Mark, I never said Roundup could not be effective on milkweed.   At a 
high enough dose it can even kill a tree.  The main point of the Nebraska 
weed scientists was that "common milkweed [Asclepias syriaca] is spreading 
and infestations are becoming more severe" (side note: Lincoln Brower
has determined that Asclepias syriaca is the larval foodplant of 92%  
of the monarchs that migrate to the overwintering sites in Mexico) 
And the weed scientists attribute this increase to these factors:

1. "Less tillage is used in crop production today than in the past, creating 
  more favorable conditions for plant establishment and growth."

2. "Tillage implements cut and drag root sections of the plant, 
     which spreads it.

3.  Cultivated land in eastern Nebraska is in row crops most of the
    time, which provides a favorable environment for common milkweed.

4. Irrigation and fertilizer use are practices that enhance common 
    milkweed as well as crop growth."

5. "Herbicides are widely used today which often do not harm common
     milkweed, but control most annual weeds that would otherwise
     compete with it."

In my own milkweed garden , for example, I intentionally sprayed 
Roundup a month ago in order to kill competing annual weeds.
Today, these annual weeds are dead, but healthy milkweed is emerging 
from underground milkweed rhizomes.
In this way, a monarch gardener can use Roundup to create a 
monoculture of milkweed for maximum monarch production.

The public, however, only hears very negative information about 
herbicides and monarchs.

Like last month in a British newspaper Lincoln Brower told the

"I think the big lesson is that in the United States... the
real threat are the herbicides killing the milkweeds and
other plants the monarchs use for food"

Back in July 1988 Dr. Brower wrote an article in which he predicted the
likely end of the monarch migration by the year 2000.  In 
the article titled "A Place in  The Sun" Dr. Brower stated: It's fabulous 
migration...could well disappear by the end of this century"

But four months ago (Dec. 2001) the monarch overwintering 
population in Mexico was measured at 110 million butterflies which is 
about 40% ABOVE normal.

Despite this experience, Dr.Brower continues to predict the imminent
end of the monarch migration.  Just two weeks ago he spoke at Colorado
State University and had this to say:

Subject: Re: Re: Comments on: Weather deals serios blow to monarchs
Date: Wed, 3 Apr 2002 22:01:57 -0700
From: "anita lahey" <anitalahey at>
To: "Paul Cherubini" <monarch at SABER.NET>
References: <200203202157.g2KLvPo26846 at>

Well, Paul, I just heard Dr. Brower speak today here at 
Colorado State University. We don't have long to wait to find 
out which of the two of you is correct: he predicts complete
Monarch extinction within 10-20 years. He showed us a picture 
of one of his assistants buried up to his neck in dead
Monarchs. They were three feet deep. Pretty convincing evidence 
to me. He also showed a graph which correlated forest thinning to 
monarch mortality.



   For subscription and related information about LEPS-L visit: 

More information about the Leps-l mailing list