Weed biology (was information-based farming)

S. A. Modena samodena at csemail.cropsci.ncsu.edu
Sat Sep 12 16:53:07 EST 1992


In article <1992Sep12.100714.6703 at iscsvax.uni.edu> klier at iscsvax.uni.edu writes:
>samodena at csemail.cropsci.ncsu.edu (S. A. Modena) writes:
>
>I believe that our near-total reliance on spray-and-pray has
>allowed us to forget many of the *cultural* controls practiced only
>50 years ago.  The recent weed texts spend MUCH more space on what-kills-
>what than they do on the life history of the species.  Pick up Muenscher's
>old weeds book and compare to a modern text.  My contention has always
>been that you are better able to deal with a weed when you understand
>its biology and you are better equipped to bring a variety of low-cost
>controls into play.  

Kay is zeroing in on exactly what I mean by "weed biology":  really
understanding the life cycle parameters and ecology of weeds and
let's not forget genetics, could move us far forward is weed management.
Note I say weed management, and not weed control.  It's almost a 
delusion to say we can control weeds.  Management implies a weighing
of options and understanding that there are a range of "costs" and
consequences associated with each alternative strategy.

Even in spray situations: I've talked with people who know by experimentation
that there are situations in which it is possible to apply herbicides
at 10% of recommended label rate and still achieve excellent results.
But these people are paying attention to *many* factors simulataneously,
like planting date, tillage, soil type, weather regime, microenvironment
characteristics.  Very savey, very complex situational analysis.  And they
grin all the way to the bank:  because they are banking the money that others
are wasting.  Every input that is inappropriate, unneeded or excessive
is subtracted from net profit and requires long term interest payments.

And though I keep mentioning weeds, I am learning more through a project
involving corn ear worm in soybeans and cotton.  In any year 70% of
the soybean fields in NC do not need any chemical applications for CEW.
In part this is due to the record low level of corn production in NC.
In point of fact, depending on one's location to corn fields and
overall production mix of crops and tillage and planting dates, one can
almost predict months ahead the likelihood that particular soybean
fields are never likely to suffer CEW damage that is cause for concern.

Dissemination of what we already know and continued producer education
are key issues in Integrated Pest Management.

>
>I think this is nowhere more evident than in home lawns, where pesticide
>and herbicide use per acre is much higher than on an average "chemical
>farm".   We're always looking for the easy way out, the no-brain solution.
>Probably the most common question I get here in the herbarium from the 
>general public is, "I found this in my yard.  How do I kill it before
>it takes over?"  About 75% of the time, the species involved is a
>garden plant that would never compete well with a well cared for lawn.*
>And the low tech method, hand-weeding, might require 10 minutes to 
>eradicate the "problem".

One of the most disturbing things I see is the hardware outlet or
K-Mart with it's wall of "garden and lawn" chemicals.  Though
there rarely are any glass containers, I regard that concentration of
that much chemical in one place, stacked so high and in the hands of
personal that sure do not understand the consequences possible, just
makes me shutter.......I used to be a chemical laboratory technician
and the company I worked for was very, very safety strict when it
came to bulk chemical storage and handling.

>
>* This year's pest species in lawns: tomato and pepper plants (sewage sludge
>application), Pelargonium seedlings, Poa annua (not a problem in this area),
>and a Cardiospermum halicacabum (which is not winter hardy here).  Each 
>of these homeowners wanted to apply a couple of tons of herbicide to their
>lawns.
>
>Kay Klier     Biology Dept    UNI

Some states, like Florida and California, have Master Gardeners which
are "extensions" of the urban Extensions Agents...and might begin to
make a dent in just the homeowner educational problem you are alluding to.

Steve
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|     In person:  Steve Modena     AB4EL                           |
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