[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Wasp statistics and Re: generalizations
Jack Dingler wrote,
>
> I'm running out of time to write this post so there isn't much more
> rambling room, so I'd like to spawn an ecosystem discussion. :)
Me too.
>
> Anyone have any good data on the number of paper wasps needed to keep an
> area essentially caterpillar free? I have three large nests with two
> species near my yard. With a total of approximately 50 wasps. Since
> the nests became well established, I have not seen but a few
> caterpillars and the damage to my lettuce and cabbage has been
> negligible. I am also interested in information on how I might increase
> their numbers earlier in the season so that my spring losses are
> smaller.
Read "Common-Sense Pest Control" by Olkowski, Daar & Olkowski
(1991. Newtown, Ct.:Taunton Press) A really first rate text that deals with
ecosystem gardening in some detail. Two quotes from that book:
"The beneficial role of the paper, or umbrella, wasps has received more
attention. Researchers have attempted to increase their numbers by building
artifical nesting locations and measuring their predation rates. Studies
have
shown that more nesting sites can increase their impact on garden and
agricultural pests such as the cabbage butterfly (pieris rapae) and tobacco
hornworm (Manducta sexta)."
In the chapter of Garden Design and Maintenance:
"Many of the predatory and parasitic insetcs that feed on garden pests
need nectar and pollen frrom flowers for nourishment in order to lay eggs.
The California Department of Transportation capitalized on this fact in
controlling a catepillar pest on median strip plantings on roadways. The
objective was to increase the number of parasitic miniwasp attacks on pest
catepillars. The parasitoiides were already present in these plantings and
did a good job of controlling the catepillar through early June of each
year,
but after that the rate of parasitism fell dramatically.
In work carries out by Dudley Pinnock and James Milstead at the University
of
California in the early 1970s, several plants were examined for
attractiveness
to the beneficial parasitic miniwasp and for a tendency to flower from June
through the summer months. Ultimately one plant was selected and tested in
field trials. The increase in parasitism was dramatic and effective .....
snip
Unfortunately, there has been too little research into which plants can be
added
to which settings to aid the home gardener in biological control of garden
pests."
I think your bottom line is to encourage diversity in your garden and to
continue to
look at the paper wasps as beneficial. A balance will happen regarding the
wasps and
the catepillars but perhaps not by our time schedule
Bill
---------------------------------------------------------
The rec.gardens.ecosystems FAQ can be found at the group's homepage
http://sunsite.unc.edu/InterGarden/rge.html
submissions can be mailed to: ecosys-submit@sunsite.unc.edu
the moderators can be contacted at: ecosys-admin@sunsite.unc.edu
References: