Jo Holloway Green peach aphid identification & lifecycle 2014-0805

Green Peach Aphid

Dr Jo Holloway

Research Entomologist

5 August 2014

5 August 2014

Aphid Forms

Two forms, same species:

– Winged (alate)

– Non-winged (aptera)

Aphid Characteristics 1 Hemiptera (bugs)

– Piercing and sucking mouthparts

Segmented antennae

Tubercle– Small humps between

the bases of the antennae

– Shape often used as species identifier

Aphid Characteristics 2

Siphuncles (cornicles)– Paired tube-like projections – Wax-secreting structures– Shape and sizes

characteristic

Cauda (tail)– Tail-like process terminating

the end of body– Shape, size and hair pattern

characteristic

BWYV Transmission

Transmitted at 97% efficiency by GPA

Lower efficiency by cabbage aphid (14%), cowpea aphid, and perhaps turnip aphid

Cowpea aphid

Turnip aphid

Cabbage aphid

Green peach aphid

Green Peach Aphid: Identification 1

Colour may vary: – yellow, green, orange, pink

Body slightly shiny Antennae nearly as long as body Red eyes

Dark thorax Green abdomen Dark patch on abdomen

Non-winged:Winged:

Green Peach Aphid: Identification 2

GPA: Head

Source: AphID http://aphid.aphidnet.org/Myzus_persicae.php

Non-Winged Winged

GPA: Abdomen

WingedNon-WingedSiphuncle: non-winged

Source: AphID http://aphid.aphidnet.org/Myzus_persicae.php

Canola Aphids

Cabbage aphid Turnip aphid Green Peach Aphid

Dark patchabdomen

Dark barsabdomen

Dark head/thorax

Siphunclesshorter thancaudal base

Siphuncleslonger

Siphunclesreachcaudal base

Aphid Mummies

Indicators of parasitism (biological control)

Aphid Lifecycle Sexual and parthenogenic

reproduction

Summer: populations survive on host plants on roadsides etc.

Autumn: winged aphids move into crop edges

Winter: slow rates of development

Spring: rapid increase in populations through asexual reproduction

Winged forms produced often due to overcrowding or decrease in food quality

GPA: Reproduction & Development

Development can be rapid:– 10-12 d complete generation, but up to 50 d in cooler

conditions– >20 generations annually mild climates

Development rates favoured when daily max temps reach 20-25°C

Number offspring reported at 20-80 per wingless female– Higher rates observed on virus infected plants (Kuo

1991)

GPA: Habitat

Generally found on underside of leaves Occurs singly, or in small groups (not large

colonies like cabbage or turnip aphids) Broad host range: over 130 plant families (eg

canola, lupins, pulses, vegetables, fruit trees etc) Frosts and heavy rain may suppress populations,

but are unlikely to fully control them– Research suggests no significant mortality after 7-10

days with -5°C frosts each night (Howling et al 1994)

Ecological Effects That Led to Current Situation Weather conditions:

– Summer rain + Mild conditions late Feb/March to June– “Green Bridge”

Impact on aphid numbers: – Conditions optimal for aphid increase– Greater than normal number of generations– Higher fecundity and survival– Increased flight activity

Agronomic EffectsVarieties

Varietal differences exist , but there is no tabulated data on current variety reactions.

Standing stubble

Damage is less in crops sown into standing stubble vs bare earth (typical aphid behaviour)

Bare patches in paddock are affected first, then aphids spread to the remainder of paddock

Sowing date

Worse in early sown crops: likely linked to aphid flight timing

Source: SARDI