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Common name: Melon aphid

Scientific name: Aphis gossypii Glover

Common name: Greenpeach aphid

Scientific name: Myzus persicae (Sulzer)











Economic Importance


The aphids constitute a large group of small, soft-bodied insects that are frequently found in large number sucking the sap from the stem or leaves of plants.


Melon and green peach aphids attack a number of crops and are vectors of many viruses attacking sweetpotato and other crops.


Geographical distribution


Worldwide in distribution.



Aphids usually attack the growing shoots and expanding leaves. They feed on the lower surface of the leaves and injure the plants by sucking the sap.  The leaves become deformed as they expand.  They may curl down at the edges, and become wrinkled or puckered.  Feeding on expanded leaves (more common with green peach aphid) may result in pale stippled areas of feeding damage between the veins. 

During heavy infestation, the vigour of the plant is greatly reduced, stunting growth of the plants.  Leaves of such stunted plants are pale and may have yellow interveinal areas.

Both species of aphid transmit several virus diseases in sweetpotato and in other crops.

Infestation of the two aphid species could be differentiated by the production of the honeydew. M. persicae produces less honeydew than A. gossypii.



These insects can be recognized by its pear-like shape, a pair of cornicles at the posterior end of the abdomen and fairly long antennae; winged forms can usually be recognized by the venation and relative size of the front and hind wings.

The cornicles of aphids are tube-like structures arising from the dorsal side of the fifth or sixth abdominal segment.

Melon aphid

Nymph. The nymphs are green to brown and moult four times before reaching the adult stage. The nymphs look like the wingless adults except for their small sizes and softer body.

Adult. The adults are yellowish to green or black about 1.5 mm long.

Green peach aphid

Nymph. The nymphs are similar to wingless adults but are  smaller in size.

Adult. The adults are small to medium sized, 1.2-2.5 mm long. They are usually green with darker thorax. The antennae are two-thirds as long as the body. The cornicles are clavate and fairly long. The face when viewed dorsally has a characteristic shape. This species generally produces little honeydew.

Biology and ecology

The life cycle of aphids is rather unusual and complex. The females reproduce parthenogenetically. Several generations may be produced in short period of time. The first generation usually consists of wingless individuals, however, when a colony becomes too crowded, winged individuals appear. The winged forms migrate to a different host plant and begin new colonies, a generation consisting of both males and females is produced, and the reproductive process continues.

Aphids secrete honeydew which is emitted from the anus; the honeydew consists mainly of excess sap ingested by the insect, to which are added excess sugars and waste materials. This honeydew may be produced in sufficient quantities to cause the surface of leaves to become sticky.

Host range

Aphis gossypii - Apart from sweetpotato, this species also damages citrus, cocoa, coffee, cotton, cucurbits, eggplant, okra, pepper, potato and also ornamentals like Hibiscus.

Mysus persicae - can occur on bitter gourd, cabbage, cauliflower, condol, chayote, eggplant, lemon, lettuce, loofah, melon, mustard, pechay, pomelo, potato, raddish, squash, tomato, tobacco, watermelon, and on weeds like Prunus persica, P. nigra, P. tanella, and P. serotina.


Biological control

The aphids are attacked by a number of ladybird beetles (Menochilus sexmaculatus, Coelophora inaequalis and Scymnus sp.) a chrysopid predator (Chysopa oculata), larva of syrphid fly (Ischiodon scutellaris),  spiders (Oxyopes javanus and Thomisus sp.), a  brachonid wasp (Opius sp.) and entomopathogenic fungi.

Chemical control

Insecticides applicable for aphids include organophosphorous, pyrethroids , carbamates and neonicotinoids. Apply insecticides only when necessary.  Aphids have been found to develop resistance to insecticides in areas where they are regularly used. 

Often, preditor insects are more severely affected than the aphid, with the result that aphid populations increase after insecticide use.


Amalin, D.M. and E. A. Vasquez. 1993. A handbook on Philippine sweetpotato pests and their natural enemies. International Potato Center (CIP), Los Baños, Philipppines. 82 p.

Ames, T., Smit, N.E.J.M., Braun, A.R., O’Sullivan, J.N., and Skoglund, L.G. 1996. Sweetpotato: Major pests diseases, and nutritional disorders. International Potato Center (CIP). Lima, Perú. 152 p.

PANS. 1978. Pest Control in Tropical Root Crop. Manual No. 4. Center for Overseas Pest Research. London 235 p.

Vasquez, E.A. and C.E. Sajise. 1990. Pests of sweet potato: Insects, mites and diseases. Philippine Root Crop Information Service, Philippine Root Crop Research & Training Center. 65 p.


Contributed by: Erlinda Vasquez, Vilma Amante and Jane O'Sullivan


Economic importance

Geographical distribution



Biology and ecology

Host range



Melon aphids attacking undersurface of a sweetpotato leaf (E. Vasquez).

Severely puckered leaves due to aphid attack (E. Vasquez).

Wrinkling and curling on leaves due to melon aphid attack (E. Vasquez).


Evidence of melon aphids includes leaf puckering and honeydew, which makes dust stick to the leaves (J. O'Sullivan).


A severely stunted crop having suffered persistent heavy aphid infestation (J. O'Sullivan).


A winged adult aphid.


Green peach aphids attacking under  surface of a sweetpotato leaf (E. Vasquez).

Feeding damage by green peach aphid, seen as pale mottled or speckled interveinal patches.