Cotton Aphid

Classification and Description:  Aphids are slow-moving, soft-bodied insects.  Most aphids can be recognized by the occurrence of two cornicles (i.e., “tail pipes”) on the end of the abdomen.  The cotton aphid, Aphis gossypii (Homoptera: Aphididae) is the most common aphid found in cotton.  Cotton aphids are only about 2-3 mm in length as adults.  Like all aphids, both adults and nymphs have piercing-sucking mouthparts.  Both winged and non-winged adults are encountered, but non-winged adults are most common in cotton when aphid populations are high.  Winged adults are typically black and have two pair of transparent wings.  Non-winged adults and immature stages vary considerably in color from pale yellow, bluish-green or grey-black. 

Hosts and Distribution:  The cotton aphid, also known as the melon aphid, has a wide host range and is distributed throughout the United States.

Life History:  Like many species of aphids, cotton aphids can reproduce sexually or asexually.  Asexual reproduction occurs during summer months when populations are found on cotton.  During asexual reproduction, each female gives live birth to 30-80 immature females.  Nymphs are born pregnant and begin giving birth in 4-7 days during normal summertime temperatures.  Aphid populations can grow very rapidly, and many generations are produced each year.

Pest Status and Injury:  Aphids occur in most cotton fields every year but only occasionally cause economic damage.  Significant damage appears more likely when environmental conditions such as dry weather are already stressing cotton growth.  Aphids are often found on the undersides of leaves or feeding on the terminals and other parts of cotton plants.  They feed by sucking sap from phloem tissue.  Heavily infested leaves will often curl downward along their edges.  The accumulation of honeydew causing the appearance of sticky and shiny leaf surfaces often indicates the presence of aphids (or whiteflies).  Severe infestations can seriously stunt plants and reduce yields, particularly if populations persist for a long period of time.  Honeydew secretions on open bolls may result in lint staining or “sticky cotton.”  In Tennessee, where cleansing rains are common prior to harvest and late-season aphid infestations are generally low, this is rarely a concern. 

Management Considerations:  Aphid populations are flared by use of many insecticides that reduce populations of important predators and parasites.  Natural enemies often keep cotton aphid populations under control.  These include several species of lady beetles (adults and larvae), lacewing larvae, a small parasitic wasp (Lysiphlebus testaceipes, causing the appearance of aphid “mummies”) and the “aphid fungus” (Neozygites fresenii).  Outbreaks of Neozygites fresenii typically occur in July.  These epizootics often reduce aphid populations to non-economic levels.

Insecticides are recommended during the early season when aphids are present on numerous plants and some leaves are curled around the edges.  During mid- and late-season, aphid treatment is not suggested unless aphids are very numerous and honeydew is accumulating.  Recommended insecticides are listed in the Insect Control Recommendations for Field Crops (PB1768).

Print-Ready PDF Publication (Cotton Aphid W028)