2021 Aphid Monitoring
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2021 Aphid Monitoring
Landscape & Garden Treasure Valley
Aphid (Family Aphididae)
Posted on: May 27, 2021 by Nic Usabel
Many different aphid species feed on ornamental landscape
plants. Aphids feed by inserting thin mouthparts into the plant phloem and
sucking out sap. Aphids are globular and 1 to 6 mm long depending on life stage
and species. They can be black, brown, yellow, red, gray or green. The legs and
antennae are usually long and fragile. Aphids may be wingless or have
functional wings. The offspring are smaller than the adults and are always
wingless.
Aphids excrete a sweet, sticky liquid called honeydew. When
aphids are abundant, honeydew often completely coats leaves and other objects below, giving infested plants a sticky or varnished appearance.
SCOUTING & MONITORING
- Scout plants at least twice weekly when plants are young and
growing rapidly. - Check the underside of leaves where aphids congregate.
CONTROL – CULTURAL & MECHANICAL
- On Shrubs and garden plants aphids can sometimes be managed
by simply washing aphids off plants with a forceful jet of water. - If natural enemies are present such as lady beetle larvae or
lacewing larvae these voracious predators will help to manage the control of
aphids without chemical application. - Several species of minute stingless wasps
will also parasitize aphids. - Encourage natural enemies by planting yarrow, alyssum, herbs
and other plants with small attractive flowers. - Manage nitrogen levels.
- Use row covers
CONTROL – CHEMICAL
Thresholds help to determine whether and when to treat for
aphids.
- When plants are young, aphid populations are increasing and
aphids occur on 50-60% of the leaves. - Aphid populations remain at 8 to 10 or more per leaf for two
or more consecutive weeks.
If high numbers of aphids regularly occur and
injure plant or are not sufficiently controlled by beneficial insects an
insecticide could be used for control. See publication links for suggested
control.
UPCOMING PROGRAMMING
For upcoming programming activities view that attached documents
- U and I Together: An activity series where all ages can learn!
- Creating a Fire-Resistant Landscape
» https://pnwhandbooks.org/insect/hort/landscape/common/landscape-aphid
» https://extension.usu.edu/pests/research/aphid-pests-on-vegetables
» https://extension.colostate.edu/topic-areas/insects/aphids-on-shade-trees-and-ornamentals-5-511/
