Agriculture Reference
In-Depth Information
Chapter 7
S
TEM
B
ORING OF
S
OYBEAN BY
D
ECTES TEXANUS
(C
OLEOPTERA
:
C
ERAMBYCIDAE
)
AND THE
N
ATURE
OF ITS
I
MPACT ON
Y
IELD
J. P. Michaud, J. A. Qureshi
*
, A. K. Grant, and J. L. Jyoti
Kansas State University, Department of Entomology, Agricultural Research Center-Hays,
Hays, Kansas, 67601, USA
A
BSTRACT
The yield of Roundup Ready
®
soybean plants infested by larvae of
Dectes texanus
LeConte was compared to that of uninfested plants obtained from the same fields in two
successive years in west-central Kansas. Plants were significantly larger in all respects in
2006 than in 2005, due largely to a lower plant population, but there was no reduction in
either pod number or total seed weight as a consequence of larval boring in either year.
Infested plants had marginally greater total seed weights than uninfested plants in 2005,
an effect attributed to females preferring larger plants for oviposition when average plant
size was small. Mean stem diameters were not notably different between infested and
uninfested plants as observed in certain earlier studies, suggesting that
D. texanus
populations may now be exploiting smaller size classes of soybean plants to a greater
extent. Although our results suggest no impact of larval boring on yield, the possibility of
some yield impact under different growing conditions cannot be ruled out. However, any
yield losses arising from
D. texanus
larval boring are likely small compared to those
arising from pre-harvest lodging that results when mature larvae girdle plants prior to
overwintering.
Keywords
Glycines max
, larval boring, yield loss
*
Current address: University of Florida, Southwest Florida Research and Education Center, 2686 SR 29,
Immokalee, FL, 34142.
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