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Large cotton aphid, Melon aphidOn this page: Identification & Distribution Other aphids on the same host Damage & Control
Identification & Distribution
Adult apterae of Acyrthosiphon gossypii are greenish (or sometimes yellowish), with adults and immatures dusted with fine wax (cf. Acyrthosiphon pisum, where adult apterae have no wax bloom and are therefore conspicuous in colonies). Their antennal tubercles are well developed, with their inner faces divergent. The antennae are almost 1.4 times as long as body, and the terminal process is 3-3.5 times as long the base of last antennal segment. They have 1 or 2 secondary rhinaria on antennal segment III. The siphunculi are pale and attenuated distally, thinner than the hind tibiae at their respective midpoints, and 2.5-3.5 times the length of the cauda (cf. Acyrthosiphon pisum, whose siphunculi are thin and cylindrical distally, 1.2-1.9 times the caudal length). The siphunculi have no subapical zone of polygonal reticulation (cf. Macrosiphum euphorbiae, which does have a subapical zone of polygonal reticulation on its siphunculi). The cauda is tongue-shaped and bears 3-6 hairs. The body length of adult Acyrthosiphon gossypii apterae is 2.5-3.8 mm.
Images above by permission, copyright Sunil Joshi & Poorani, J. Aphids of Karnataka. (accessed 12/8/20).
Acyrthosiphon gossypii alatae are coloured similar to the apterae, and bear 9-12 secondary rhinaria.
Image above by permission, copyright Sunil Joshi & Poorani, J. Aphids of Karnataka. (accessed 12/8/20).
Acyrthosiphon gossypii is a warm-country species that feeds on members of the Fabaceae, especially various beans (Dolichos, Phaseolus, Vigna) as well as Malvaceae (including cotton and okra) and Zygophyllaceae (bean capers and caltrops). They have also been reported on certain trees such as the black locust (Robinia pseudacacia) and Japanese pagoda tree (Styphnolobium japonicum). It is a pest of cotton in central Asia. The species is anholocyclic over much of its range, but there is a holocycle on camelthorn (Alhagi camelorum) in central Asia. Its distribution extends from China and India through south-west and central Asia to the Middle East, North Africa, and parts of southern Europe.
Other aphids on the same host
Acyrthosiphon gossypii has been recorded on two Gossypium species (Gossypium herbaceum, Gossypium hirsutum).
Acyrthosiphon gossypii has been recorded on one Phaseolus species (Phaseolus vulgaris).
Acyrthosiphon gossypii has been recorded on one Robinia species (Robinia pseudoacacia).
Acyrthosiphon gossypii has been recorded on one species of Abelmoschus (Abelmoschus esculentus).
Damage and control
Acyrthosiphon gossypii is a serious pest of cotton in central Asia, and is potentially harmful to legumes and cotton in the Iberian Peninsula and other parts of Western Europe. In western China it is a significant pest of cotton, invading crops in spring and peaking in mid-June to early July (Gao et al., 2013). Feeding on cotton leads to curling of leaves, gradual fading of tender shoots and premature fruit drop. Sirjani & Rezvani (2005) determined the economic injury level (EIL) for the large cotton aphid in the cotton fields of Kashmar in Iran. The results indicated that the EIL for Acyrthosiphon gossypii in Kashmar was 6.3-6.9 aphids per 3 upper leaves of the stem.
Müller (1975) surveyed the biology, host range and geographical distribution of this aphid in Sudan. There he found that Fabaceae, particularly Vicia faba, was the preferred host. He concluded there were different biological races of Acyrthosiphon gossypii in different parts of its distribution.