Hi Alexandra,
This was going to be off sanet, until I realized that the commentary
that follows raises some interesting questions that other subscribers
might provide answers for.
Wednesday, January 12, 2000, 9:04:03 PM, you wrote:
AS> Larry Phelan at Ohio State has researched the effect of soil
AS> management on insect feeding preference of European corn borer -
AS> see below.
The format of the data you present below is similar to that used by
Uncover. Is that where you got it by any chance?
The variables they look for could be significant in the context of
other issues of interest to me and the fact that OSU (among other
institutions, I assume) is doing these series, indicates a greater
research capacity than that existing when I was working on these
issues in the US during the past century (20 some years ago).
If determining factors like "Photosynthetic Potential, Leaf-Mineral
Profiles, and Biochemical Profiles measured by Near-Infrared (NIR)
Spectroscopy" are now relatively standard procedures and the
infrastructure for implementing them is fairly ubiquitous (and this is
exactly what I'd like some feedback about: the extent to which this is
true), it's going to be easier than it used to be to follow up on some
unfinished studies.
Is this a valid supposition? (I'm asking for comments).
(Variants like ovipositional preference for various pests may be no
less significant, but documenting these never required crossing
departmental boundaries, the politics of which proved too formidable
for a some of the lesser hearts involved back then).
The results of the above research vacuum is that at least one serious
mismanagement of plant propagation was *never* questioned and
subsequently became standard practice (and has now been integrated
even into organic agriculture), much as a number of folks (including
some on this list) would like to see happen with GMOs. (There are
other similarities between the two issues that I've discussed
elsewhere).
I have close relatives at the postdoctoral level in the OSU system
(although not in botany) and will probably follow this up with OSU
also, in direct relation to what I have in mind. My purpose here (this
post) is to determine just how common is the capacity to determine the
variables mentioned.
Thanks in advance.
Douglas Hinds - CeDeCoR, A.C.
Centro para el Desarrollo Comunitario y Rural, Asociacion Civil
(Center for Rural and Community Development,
a Mexican non-profit organization)
Cordoba, Veracruz; Cd. Guzman, Jalisco & Reynosa, Tamaulipas Mexico
dmhinds@acnet.net, cedecor@acnet.net,
cedecor@ipnet.com.mx, dhinds@prodigy.net.mx
*********** REPLY SEPARATOR ***********
AU: Phelan,-P.L.; Norris,-K.H.; Mason,-J.F.
TI: Soil-management history and host preference by Ostrinia
nubilalis: evidence for plant mineral balance mediating
insect-plant interactions.
SO: Environ-entomol. Lanham, Md. : Entomological Society of
America. Dec 1996. v. 25 (6) p. 1329-1336.
CN: DNAL QL461.E532
LA: English
DE: ostrinia-nubilalis. zea-mays. oviposition-. organic-soils.
soil-fertility. soil-management. ammonium-nitrate. cattle-manure.
composts-. leaves-. mineral-content. protein-content.
nutrient-balance. photosynthesis-. growth-.
dry-matter-accumulation. stomata-. leaf-conductance.
hosts-of-plant-pests. pest-resistance. models-.
AB: Organic-farming practitioners have long suggested that
maximizing soil biotic activity results in crops of reduced
susceptibility to pests. In the current study, we examined the
ovipositional preference of Ostrinia nubilalis (Hubner), the
European corn borer, on sweet corn grown in the greenhouse using
soils from neighboring organic and conventional farms and
fertilized with NH4NO3, cow-manure compost, or left unamended.
In addition to ovipositional preference, we compared
photosynthetic potential, leaf-mineral profiles, and biochemical
profiles measured by near-infrared (NIR) spectroscopy. Significant
variation in O. nubilalis oviposition among fertilizer treatments
was measured for plants in conventional soil, but not for those in
organic soil.
Photosynthetic parameters, notably net photosynthesis and stomatal
conductance, correlated strongly with plant biomass accumulation,
but no correlations with O. nubilalis preference were detected. In
contrast, a quadratic model of 3 leaf-mineral levels (Zn, Al, and
N) showed a strong relationship with O. nubilalis oviposition
(adjusted r2 = 0.71); plant growth was best described by a
quadratic model of N alone (adjusted r2 = 0.69).
The greatest differences in NIR spectra were caused by protein,
and soil-fertilizer combinations producing the lowest protein
levels were those whose plants received the greatest number of O.
nubilalis eggs. We suggest that differences in corn acceptability
to O. nubilalis is at least in part mediated by plant mineral
balance, which incorporates both absolute levels and ratios of
minerals, and that an optimal balance of these minerals is more
likely to occur in organically managed soil because of an inherent
property of reducing variation in mineral availability in those
soils.
AS> Alex Stone
AS> Dept. Soil Science
AS> Univ. of WI-Madison
AS> 1525 Observatory Dr.
AS> Madison, WI 53706
AS> Phone 608-262-0132
AS> Fax 608-265-2595
AS> agstone@facstaff.wisc.edu
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