Pacific Pests and Pathogens Pacific Pests & Pathogens - Full Size Fact Sheets

Melon aphid (038) Print Fact Sheet

Common Name

Melon or cotton aphid. There are many aphids attacking a wide range of crops; Aphis gossypii, described here, is common in Pacific island countries.

Scientific Name

Aphis gossypii


Worldwide. In tropical, sub-tropical, and temperate regions. Asia, Africa, North, South and Central America, the Caribbean, Europe, Oceania. Aphis gossypii is recorded from American Samoa, Australia, Cook Islands, Fiji, French Polynesia, Guam, Kiribati, Marshall Islands, Federated States of Micronesia, New Caledonia, New Zealand, Niue, Northern Mariana Islands, Papua New Guinea, Samoa, Solomon Islands, Tokelau, Tonga, Tuvalu, Vanuatu, and Wallios & Futuna.


 Aphids occur on many crops, ornamentalsand weeds; they are common on cucurbits (cucumber, melon, watermelon) and taro. They are also found on banana, bean, capsicum, chilli, citrus and eggplant.

Symptoms & Life Cycle

Males are rare or not produced in tropical countries. Eggs are not laid. Females give birth to living young without mating. The young are adult in 4-7 days, after moulting four times. They then produce four to six young a day, up to 50 each. Because of this method of reproduction, populations grow rapidly, with many generations in a year.

Spread occurs by the winged forms of the aphid, and also long distance in winds. Spread also occurs associated with the international movement of plants and plant parts for food and propagation.


Aphids cause direct and indirect damage:

Detection & Inspection

Look for groups of round, green (some may be light green, others dark green, almost black) insects on the underside of young leaves, on shoots and buds (Photo 1). They are about 1 mm long, with long antennae about the length of the body, and two tubes at the rear called "cornicles". Sometimes, winged forms occur, up to 2 mm long with prominent veins (Photo 3). It is difficult to see the detail of the body with the naked eye. Look for ants, they are often present, tending the aphids for their honeydew.


Aphid predators and parasites usually keep populations low. The most common are ladybird beetles (adults and larvae) (Photos 4,5&6), syrphid fly larvae (Photo 7), lacewing larvae, and tiny parasitic wasps that lay their eggs in the adult aphids. The wasp larvae develop in the aphids eating the inside parts and turning the aphids into empty shells, called "mummies" (Photo 8). Two impoprtant parasitoids are Lysiphlebus testaceipes and Aphidius colemani. Both exist as a number of different strains, so it is important to match the strain with the aphid strain and the environmental conditions.

Note, ants tend aphids for their honeydew. By doing so, they protect them from the activities of parasites and predators. To manage aphids, it is important to remove the ants, so that biological control can operate.


Before planting:

During growth:

After harvest:

If ants are present, find the nest, and if not too close to the plant with aphids, destroy the nest with boiling water. Without ants, predators and parasites may bring about natural control.

Alternatively, use:

AUTHORS Helen Tsatsia & Grahame Jackson
Information from Waterhouse DE (1998) Biological control of Insects: Southeast Asian Prospects. ACIAR Monograph no. 51, 548pp. Photo 6 Graham Teakle. Canberra, Australia. Photo 8 Caroline Smith. University of Tasmania, Australia.

Produced with support from the Australian Centre for International Agricultural Research under project PC/2010/090: Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production, implemented by the University of Queensland and the Secretariat for the Pacific Community.

This fact sheet is a part of the app Pacific Pests and Pathogens

The mobile application is available from the Google Play Store and Apple iTunes.

Pacific Pests and Pathogens Android Edition      Pacific Pests and Pathogens iOS Edition            Australian Centre for International Agricultural Research