How to Manage Pests
UC Pest Management Guidelines
Aphids — General Considerations
In this Guideline:
In addition to aphids described in this guideline, there are several
other species that may be found on cereals throughout the year. Many occur in
extremely low numbers and cause no damage. If, however, you encounter large
numbers of an aphid or aphids that do not fit any of the following
descriptions, please contact your farm advisor or county agricultural commissioner
immediately. New species occur frequently, and your assistance in finding these
is greatly appreciated.
CHARACTERISTICS USED IN IDENTIFICATION
The antennae are appendages arising one each from the side of the
head and function as sense organs. The cornicles are tubular structures that
arise one each on the side of the body near the rear end. The cauda is a structure resembling a tail that arises from
the tip of the abdomen. Depending on species, it may be elongated, knobbed,
triangular, or other shapes.
All aphids associated with small grains are attacked by the same group of natural enemies.
Historically these natural enemies and the advent of warm temperatures during
spring keep aphid populations from reaching damaging levels. Natural enemies
include lady beetles, syrphid fly larvae, green lacewings, parasitic
wasps that cause the aphids to develop into mummies; i.e., their bodies become dried
and bloated and turn tan or black in color, and a fungus disease that attacks aphids, but not the plants, causing them to appear flattened and
plastered to the leaf or stem.
Check fields periodically after seedling emergence. If aphids become numerous,
increase frequency of sampling. Before tillering, sample whole plants. After
tillering, sample individual tillers. Aphids are often concentrated in spots or
near the field margin. Note the presence of such hot spots but avoid sampling
only these areas. Also be sure to look for evidence of biological control,
presence of predators, disease, and aphid mummies.
UC IPM Pest Management Guidelines: Small Grains
UC ANR Publication 3466
Insects and Mites
C. G. Summers, Entomology, UC Davis/Kearney Agricultural Center, Parlier
L. D. Godfrey, Entomology, UC Davis
Acknowledgment for contributions to Insects and Mites:
D. Gonzalez, Entomology, UC Riverside
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