How to Manage Pests
UC Pest Management Guidelines
Cowpea aphid: Aphis craccivora
Bean aphid: Aphis fabae
Pea aphid: Acyrthosiphon pisum
Green peach aphid: Myzus persicae
In this Guideline:
The two most common species encountered on beans are the cowpea
aphid and the bean aphid. The cowpea aphid, which is also
common on black-eye beans (cowpeas), is shiny black with legs and antennae that
are white to pale yellow with black tips. The bean
slightly larger than the cowpea aphid, and dark olive-green to black with
light-colored legs. The pea aphid is a relatively
large, green, somewhat shiny aphid.
Aphids damage plants by: (1) sucking plant sap which causes heavily
infested leaves to curl and stunts plants; (2) excreting honeydew which causes sticky, shiny
ultimately turn black because of a sooty-mold fungus growth; and (3) spreading
plant diseases (a large number of viruses are vectored by aphids). Infestations
frequently are localized with heavily infested leaves curled downward.
Be sure to assess levels of biological control when evaluating aphid
populations. Frequently, parasites and predators prevent aphid infestations
from becoming established throughout a field. Temperatures greater than 85°F
frequently inhibit buildup of large densities of pea and green peach aphids.
Common predators of aphids in beans include lady beetles, syrphid flies, and
lacewings. Parasitic wasps attack each of the common aphid species, turning
them into hard, crusty mummies.
Organically Acceptable Methods
Biological control is
Monitoring and Treatment Decisions
Aphid control in beans
is not always necessary. The decision to treat for aphids is based mainly on
visual inspection and the stage of crop development. Measurable thresholds are
not available. Begin inspecting for aphid problems along with other pests and
their damage when the crop emerges. Continue looking through the vegetative growth and flower bud to bloom periods.
|When choosing a
pesticide, consider information relating to the impact on natural enemies and
and environmental impact. Not all registered pesticides are listed. Always read label of product being used.
||MALATHION 8 EC
||MODE OF ACTION GROUP
||COMMENTS: Highly toxic to honey bees; do not apply when bees are present.
||2.67 lb/gal EC
||MODE OF ACTION GROUP
||COMMENTS: Ground or
air application. Highly toxic to honey bees; do not apply when bees are present.
UC IPM Pest Management Guidelines: Dry
UC ANR Publication 3446
Insects and Mites
L. D. Godfrey, Entomology, UC Davis
R. F. Long, UC Cooperative Extension, Yolo County
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