Dr Joanne Holloway, DPI NSW Wagga Wagga describes how to identify the green peach aphid (GPA) and details it's lifecycle. Talk presented 5 August 2014. More information at http://www.extensionaus.com.au/

1. Green Peach Aphid
Dr Jo Holloway
Research Entomologist
5 August 2014
5 August 2014

2. Aphid Forms
 Two forms, same
species:
– Winged (alate)
– Non-winged
(aptera)

3. 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

4. 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

5. 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

6. 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:

7. Green Peach Aphid: Identification 2

8. GPA: Head
Source: AphID http://aphid.aphidnet.org/Myzus_persicae.php
Non-Winged Winged

9. GPA: Abdomen
WingedNon-Winged
Siphuncle:
non-winged
Source: AphID http://aphid.aphidnet.org/Myzus_persicae.php

10. Canola Aphids
Cabbage aphid Turnip aphid Green Peach
Aphid
Dark patch
abdomen
Dark bars
abdomen
Dark head/
thorax
Siphuncles
shorter than
caudal base
Siphuncles
longer
Siphuncles
reach
caudal base

11. Aphid Mummies
 Indicators of parasitism (biological control)

12. 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

13. 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)

14. 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)

15. 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

16. Agronomic Effects
Varieties
 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