We. Riedell et Rw. Kieckhefer, NITROGEN-FERTILIZER MANAGEMENT AND GRAIN-YIELD LOSS TO RUSSIAN WHEAT APHIDS, Cereal Research Communications, 21(1), 1993, pp. 57-61
Laboratory research has indicated that grain yield loss to Russian whe
at aphids (Diuraphis noxia Mordvilko) in wheat (Triticum aestivum L.)
can be reduced by increased levels of nitrogen fertilizer. Field appli
cation of nitrogen fertilizer, therefore, might be a useful strategy f
or limiting grain yield loss caused by Russian wheat aphids. To test t
his hypothesis, a field experiment with nitrogen fertilizer as main pl
ot treatments and Russian wheat aphid infestation as subplot treatment
s was conducted. Soil tests from an established winter wheat field in
early spring.indicated that 78 kg ha-1 nitrogen was needed to attain a
potential grain yield of 4800 kg ha-1. Nitrogen (liquid urea-ammonium
nitrate) was then sprayed onto plants at rates of 0, 39, or 78 kg ha-
1. Plants were infested with Russian wheat aphids for a period of 17 d
ays. Plants given N fertilizer had increased plant dry weight, filler
number, leaf area, leaf chlorophyll content, and grain yield compared
with plants given no N ferfilizer. Russian wheat aphid infestation red
uced grain yield approximately 31 percent. A lack of significant inter
action between nitrogen fertilizer treatment and Russian wheat aphid i
nfestation suggests that aphid infestation affected grain yield simila
rly for all fertilizer treatments studied. These results indicate that
application of nitrogen fertilizer to winter wheat improves grain yie
ld performance independently of the effects of Russian wheat aphid inf
estation.