Pecan Aphid:
Black Pecan Aphid - Melanocallis caryaefoliae (Davis)
Yellow Pecan Aphid - Monelliopsis pecanis Bissell

Dr. Randy Hudson, Extension Entomologist, The University of Georgia, Department of Entomology, Tifton, GA 31793
Dr. David Adams, Extension Entomologist, The University of Georgia, Department of Entomology, Tifton, GA 31793

Order Homoptera: Family Aphididae

Description: Yellow and black pecan aphids are small, soft bodied insects with piercing sucking mouthparts. During the process of feeding they excrete a clear sugary material called "honeydew". Honeydew is the substance that gives pecan trees a shiny glistening appearance during epidemic aphid infestations. Sooty mold often develops on pecans following a heavy aphid infestation. Yellow aphids are characteristically yellow in appearance. Black aphids are a "dull" black in color. Shiny, polished, black, parasitized yellow aphids are often confused with the black pecan aphid. Hosts: Pecan, hickory and other members of the same plant family. Damage: Yellow and black pecan aphids can significantly reduce pecan yields. Both aphids suck photosynthates from leaves, excrete "honeydew", and reduce the flow of nutrients to nuts. Damaging infestations of yellow aphids can cause whole leaves to turn yellow and possibly shed. Black aphid damage is characterized by small, chlorotic areas on the leaflets. Heavy infestations cause rapid leaf shed. Both aphids can cause premature leaf shed, reduced nut quality, and subsequent yield reductions the following season.

Yellow Pecan Aphid Photo by: Jim Dutcher, UGA

Black Pecan Aphid Photo by: Jerry Payne, USDA

Life Cycle: Black and yellow pecan aphids have very similar life cycles. Both overwinter as eggs. Wingless females hatch in March and migrate to the newly emerging pecan leaves. These females in turn give birth to living young without mating. This first field progeny is also all female and in turn give birth to subsequent generations of aphids without mating. In early fall, winged females and males mate, and the females lay eggs that will overwinter. There are 20-30 generations of aphids per year.

Control: Black aphids usually do not require controls until late season. After mid-July, black aphids should be treated when an average of one black aphid per compound leaf is found. Also, treatments may be necessary when one or more black aphid "hits" are found per compound leaf and black aphids are present in the orchard. After July 1, treat for yellow aphids when an average of 20 per compound leaf is found and "honeydew" is heavy. Avoid treating for aphids prior to July 1 unless absolutely necessary.

In: Roberts, P. M. and G. K. Douce, Coordinators. 1999. Sucking Insects. A County Agent's Guide to Insects Important to Agriculture in Georgia. Univ. of GA, Col. Ag. Env. Sci., Coop. Ext. Serv., Tifton, GA USA. Winter School Top Fifty Agricultural Insect Pests and Their Damage Sessions, Rock Eagle 4-H Ctr., Jan. 20, 1999.

Selected References and Suggested Readings