Taxonomy

Domain	Eukarya
Kingdom	Animalia
Phylum	Arthropoda
Subphylum	Hexapoda
Class	Insecta
Subclass	Pterygota
Infraclass	Neoptera
Superorder	Paraneoptera
Order	Hemiptera
Suborder	Sternorrhyncha
Superfamily	Aphidoidea
Family	Aphididae
Subfamily	Calaphidinae
Tribe	Panaphidini
Genus	Melanocallis

Scientific Name

Melanocallis caryaefoliae

Scientific Name Synonyms

Myzocallis caryaefoliae

Callipterus caryaefoliae

Tinocallis caryaefoliae

Common Name

black pecan aphid

Description

The nymphs are tiny, greenish-yellow, soft bodied and wingless. The adults are also small (3 - 4 mm), dull black with minute white body spots, and clear unmarked wings.

Damage

The black pecan aphid feeds on both sides of pecan leaflets, causing yellowing and necrosis of areas between the lateral leaflet veins. One black pecan aphid can produce a necrotic area of about 0.27 square inches and eight to ten such spots will cause the leaflet to drop. Black pecan aphids can completely defoliate an orchard within 30 days. Black pecan aphid damage will usually be noticed first on the lowest limbs in the interior portion of the tree. As populations increase, the aphids spread up and out.

Seasonal History

All aphids on pecans have similar life histories and development. They overwinter as fertilized eggs in crevices in the bark or other protected places on the tree. Wingless female aphids known as stem-mothers hatch about late March. These stem-mothers move out to the opening buds and leaves and feed until fully grown. When grown, they give birth to living young without mating. The young are likewise all females and later, they too give birth to living young. Each black pecan aphid female reproduces for about 10 days and gives birth to about 35 young. Winged females develop during some of the generations. These winged aphids fly to other parts of the same tree or to different trees. In late fall, winged male and wingless female aphids are produced. They mate and the wingless females lay fertilized overwintering eggs on the tree. Twenty to 30 successive aphid generations may occur during the year depending upon the season. Aphids are present in orchards whenever pecans are in leaf. The black pecan aphid is normally most numerous from late July through October, although they may occur in significant numbers as early as late April.

When to Control

Black pecan aphids may cause damage as early as May but, usually do not require control before late season. When sampling for black pecan aphids, check all the compound leaves on 10 terminals per tree on at least 10 trees per orchard. Sample susceptible cultivars such as Schley, Sumner or Gloria Grande. It is very important that sample size be large enough to detect small population increases to avoid excessive damage. Prior to July 1m treat if 25% of terminals have 2 or more black aphids. After July 1, treat if 15% of terminals have 2 or more black aphids.

Originally compiled from

Archive:PPMH/Melanocallis caryaefoliae