Peachpotato aphid Myzus persicae

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This and similar species are often referred to by the name 'greenfly' (Figure 14.8).

Damage. It is common in market gardens and greenhouses. The nymph and adult of this aphid may cause three types of damage. Using its sucking stylet, it may inject a digestive juice into the plant phloem, which in young organs may cause severe distortion. Having sucked up sugary phloem contents, the aphid excretes a sticky substance called honey-dew, which may block up leaf stomata and reduce photosynthesis, particularly when dark-coloured fungi (sooty moulds) grow over the honeydew. Thirdly, the aphid stylets may transmit viruses such as virus Y on potatoes and tomato aspermy virus on chrysanthemums.

Life cycle. The aphid varies in colour from light green to orange, measures 3 mm in length (see Figure 14.9) and has a complex life cycle, shown in Figure 14.8, alternating between the winter host (peach) and the many summer hosts such as potato and bedding plants. In spring and summer, the females give birth to nymphs directly without any egg stage (a process called vivipary), and without fertilization by a male (a process called parthenogenesis). Spread is by the summer flighted females. Only in autumn, in response to decreasing daylight length and outdoor temperatures, are both sexes produced, which having wings, fly to the winter host, the peach. Here, the female is fertilized and lays

September]

Autumn and winter PEACH host

September- |Eggs| March

September

Autumn and winter PEACH host

September- |Eggs| March

September]

September

Myzus Persicae

June-September

Figure 14.8 Peach-potato aphid life cycle throughout the year. Female aphids produce nymphs on both the peach and summer host. Winged females develop from June to September. Males are produced only in autumn. Eggs survive the winter. In greenhouses the life cycle may continue throughout the year

June-September

Figure 14.8 Peach-potato aphid life cycle throughout the year. Female aphids produce nymphs on both the peach and summer host. Winged females develop from June to September. Males are produced only in autumn. Eggs survive the winter. In greenhouses the life cycle may continue throughout the year

Green Black Aphids Rose And Begonia

Figure 14.9 Roseaphid thick-walled black eggs. In glasshouses, the aphid may survive the winter as the nymph and adult female on plants such as begonias and chrysanthemums, or on weeds such as fat hen.

Spread occurs in early summer and autumn by winged females.

Figure 14.9 Roseaphid

Control. The peach-potato aphid can be controlled in several ways. In outdoor crops, several organisms, e.g. ladybirds, lacewings, hoverflies and parasitic fungi (see biological control, Chapter 16), naturally found in the environment, may reduce the pest's importance in favourable seasons. In the greenhouse, an introduced parasitic wasp (Aphidius matricariae) is available to amateurs and professionals.

The amateur gardener uses an aphicide containing pyrethrins. Two other chemicals are used by both amateur and professional horticulturists: a contact chemical bifenthrin and a soap concentrate containing fatty acids.

For the professional, there is a biological control using the fungus Verticillium lecanii, and many chemical controls, including pirimicarb used outdoors and in glasshouses as a spray, and nicotine used as a smoke in glasshouses.

There are many other horticulturally important aphid species. The black bean aphid (Aphis fabae), which overwinters on Euonymus bushes, may seriously damage broad beans, runner beans and red beet. The rose aphid (Macrosiphum rosae) attacks young shoots of rose.

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Responses

  • artemisia
    Is peach potatoe aphid the same life cycle as black bean aphid?
    8 years ago

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