Vol. 51—1997 - NorthEastern Weed Science Society

30
FIRST YEAR'S IMPRESSIONS OF WEED CONTROL IN TRANSGENIC CROPS
M.J. VanGessel, Q. Johnson, and M. Isaacs 1
ABSTRACT
weed science program at the University of Delaware had a number of trials
with gluf inate-resistant corn (Zea mays L.) and soybeans [Glycine max (L.) Merr.] and
glyphosa e-resistant soybeans. This was the first opportunity for a new weed scientist
to exami e this technology. Glufosinate- and glyphosate-resistant crops were
evaluate for effectiveness of annual weed control.
GI fosinate was compatible with ten different POST corn herbicides,
represen ing triazines, ALS-inhibiting herbicides, and benzoics. Although, in this study,
glufosina e alone was as effective as any tank-mixture.
GI fosinate appears to hve a wide window of application. Application to com
resulted n similar results when applied to 8 or 14 inch com. Although, as expected,
higher ra es (> 0.2 Ibs ai/A) were needed for later applications to obtain highest level of
control. .
A rial compared the effectiveness of glufosinate and glyphosate applied at
various t mings for weed control and yield loss potential. Glufosinate and glyphosate
applicati ns to their respective transgenic soybean varieties, provided good to excellent
control common ragweed (Ambrosia arlemisiifolia L.), jimsonweed (Datura
stramon um L.), common lambsquarters (Chenopodium album L.), and fall panicum
(Panicu dichotomiflorum Michx.) when applied from the first to fifth trifoliolate soybean
stages.
lufosinate- and glyphosate-resistant crops will provide a new and effective
approac to weed management. This technology relies on many integrated weed
manage ent principles, but as such, requires additional management on part of the
growers
I ssist. Prof., Ext. Assoc., and Dir. Res. and Educ. Ctr., Dept. Plant and Soil
ScL, U iversity of Delaware, Res. and Educ. Ctr., Georgetown. DE 19947.