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Problem: Aphids
Hosts: Aphids attack such a wide variety of
plant material that it is not practical to list individual species.
Description: Aphids are small (about 1/8 of and
inch long), soft-bodied, pear-shaped insects of many colors such as green, black, gray,
yellow or red. Some are winged during certain times of the year. Generally, aphids can be
recognized by their cornicles, a pair of tube-like structures projecting from the rear of
their bodies.
Aphids feed by sucking sap from buds, leaves, twigs and developing fruit. Leaves may be
stunted and distorted and fruit may become misshapen. Aphids can also carry a number of
plant viruses.
Many aphid species excrete a sticky substance known as "honeydew" which usually
becomes black with sooty mold. Automobiles parked under trees with large aphid populations
will often be subjected to a "rain" of honeydew.
Though aphids undergo simple metamorphosis, the life cycle is often complex. In most
species, winter is passed as eggs. Nymphs hatch out in April with several generations
occurring through the growing season. It is common for females to give birth without
fertilization (parthenogenesis) and for live young to be produced (viviparity). Different
generations may be winged or unwinged with the winged generation being the migratory
stage.
Recommendations: Aphids are usually controlled
effectively by nature. Adverse weather conditions such as beating rains and low
temperatures, as well as fungus diseases, insect predators and parasites keep the aphids
in check. Aphid enemies include lady beetles, syrphid fly larvae, aphis lions and small
wasp parasites known as braconids.
Insecticide applications destroy beneficial insects as well as pests and leave trees or
shrubs unprotected if pest resurgence occurs. Since beneficial insects play an important
role in natural aphid control, try washing aphids away with a forceful stream of water
before using insecticide sprays.
If control measures are warranted, use malathion, cyfluthrin or
permethrin. Reapplication is often needed.
References:
1. Insects and Mites Associated With Shade Trees and Woody Ornamentals, pg 10, K-State
Research and Extension Pub S-85
2. Life Histories of Common Insects, Mites and Nematodes Infesting Ornamental Plants in
Missouri, Missouri Department of Agriculture, pg C-1 through C-12
Last Update: 04/27/2004
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