Bugs only bug unhealthy plants? (fwd)

Neason Rebecca.Neason at foxinternet.net
Fri Aug 8 16:00:54 EST 1997


Allyn,

Rather than call it necessarily a counter-example, could one not argue that 
periodic swarms of insects serve the dual purpose of "cleaning up" overcrowded 
vegetation, while at the same time protecting the insect from predators?  (Because 
the insect is not available each season but only several seasons apart, the 
predator population stays lower.)  Thus, the insects are "attacking" the "stressed" 
plants, as the original post suggested.  

Just throwing out an idea.

Steve  (Maritime Climate -- USDA Zone irrelevant)



Allyn Weaks wrote:
> 
> In article <Pine.GSO.3.96.970805162355.11909A-100000 at titan.oit.unc.edu>,
> Ronald Zwaagstra <zwaagstr at sunsite.unc.edu> wrote:
> 
> >---------- Forwarded message ----------
> >Date: 4 Aug 1997 15:19:00 GMT
> >From: "Dennis R. Moore" <drmoore at mail.nospam.gte.net>
> >Subject: Bugs only bug unhealthy plants?
> >
> >It is a long held common garden wisdom that insects and diseases are
> >problematic only on unthrifty or otherwise stressed plants. My own
> >experience validates this supposition to some degree but, lately I've
> >been wondering if there is any solid research supporting this thesis.
> >Can anyone point me in the right direction? Thanks!
> 
> Haw about a well known counter example: the periodic locust plagues on the
> great plains?  Grasshoppers would increase in numbers in an area to plague
> proportions, changing their body form and eating _everything_ for miles
> around over a year or three, swarming off to different spots as they ate
> the last scraps where they were.  Eventually the swarms would fall apart
> and become mostly unnoticed solitary grasshoppers again--until the next
> time.  The eaten plant community would regenerate from the roots and from
> the seed bank, but plenty of individual plants got hosed regardless of
> health.  (Including all of the crops planted by the new immigrants, who had
> refused to believe the native american stories...).   By simplistic
> statistical arguments, local boom and bust cycles should not only happen
> sometimes, but be the norm...  Mind you, fiddling with the natural cycles
> of complex systems is as likely to make them more prominant as less, as one
> can discover in the wonderful but sometimes depressing _Dams and Other
> Disasters: A Century of the Army Corps of Engineers in Civil Works_ by
> Arthur Morgan.
> --
> Allyn Weaks  allyn at u.washington.edu
> PNW Native Wildlife Gardening:  http://chemwww.chem.washington.edu/natives/
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