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The soybean aphid has a
complex life cycle that utilizes
two very
different types of host plants.
Many species of aphids display complex life cycles with alternation
of sexual and asexual generations and host plant alternation. All
asexual generations are entirely female and are clones of the mother.
The aphids also called spring immigrants, deposit live young, called
nymphs, without sexual reproduction under upper soybean leaves.
These female offspring are mature within one week and can then produce
two to three young per day. Up to 15 generations may occur on soybean
in the summer. The proportion of nymphs that become winged
increases dramatically in
late summer.
In the fall, winged males and females are produced that seek out
buckthorn, where sexual reproduction occurs. Eggs are then laid,
and these overwinter on the buckthorn and hatch in the spring. Three
generations are produced on newly expanding buckthorn leaves before
the aphids migrate back to young soybeans.
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Introduction
