Monelliopsis

Richards, 1965

yellow pecan aphid

Species Guides

2

Monelliopsis is a of aphids (Hemiptera: Aphididae) in the Calaphidinae, established by Richards in 1965. The genus contains that are specialized feeders on pecan (Carya illinoinensis), with Monelliopsis pecanis being the most economically significant species. These aphids are known as 'yellow pecan aphids' and are important pests of commercial pecan production in North America. They have and produce honeydew, which supports growth. The genus is distinguished from the related Monellia by morphological and behavioral characteristics.

Monelliopsis caryae by (c) Bill Keim, some rights reserved (CC BY), uploaded by Bill Keim. Used under a CC-BY license.Monelliopsis pecanis by the Smithsonian. Used under a CC0 license.Monelliopsis pecanis by the Smithsonian. Used under a CC0 license.

Pronunciation

How to pronounce Monelliopsis: //moʊˈnɛlioʊpsɪs//

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Monelliopsis are recognized by their yellow body coloration and characteristic wing posture: wings are held roof-like over the body, not flat. This distinguishes them from Monellia caryella (black margined aphid), which holds wings flat over the body and has a black stripe along the wing margin. Monelliopsis pecanis lacks the black marginal stripe on the wings. stages are wingless and difficult to distinguish from other yellow species without microscopic examination.

Images

Habitat

Pecan tree (Carya illinoinensis); occurs on foliage of commercial and native pecan trees. Intracanopy distribution varies seasonally, with developing throughout the tree canopy.

Distribution

Native to North America; recorded from USA (Alabama, Arizona, California, Florida, Georgia, New Mexico, Oklahoma, South Carolina, Texas), Mexico. Introduced to Europe (Italy, Sicily, Portugal, Madeira), Africa (Egypt, South Africa).

Seasonality

typically increase later in the growing season compared to Monellia caryella. Peak abundance occurs from late summer through early fall (August-September in most pecan-growing regions). hatch in spring; multiple occur during the growing season.

Diet

Phloem sap from pecan leaves (Carya illinoinensis). Feeding occurs on leaf , with distinct probing and feeding site preferences on pecan foliage that differ from co-occurring .

Host Associations

Life Cycle

Hemimetabolous development with multiple per year. are deposited in bark crevices on twigs and trunks in late September-October. Eggs hatch in spring during bud break. Nymphs mature in approximately one week and reproduce parthenogenetically (live birth of females) during spring and summer. Sexual forms (males and females) appear in fall.

Behavior

Exhibits distinct probing with specific feeding site preferences on pecan foliage. Produces copious honeydew during feeding. Winged forms disperse to new trees. can increase rapidly under favorable conditions due to parthenogenetic and short time.

Ecological Role

Herbivore and pest of pecan trees. Heavy cause direct damage through sap removal and indirect damage via honeydew production that supports , reducing . Serves as prey for diverse aphidophagous including lacewings, lady beetles, predatory , and syrphid flies. for including Aphelinus perpallidus.

Human Relevance

Significant economic pest of commercial pecan production. Monelliopsis pecanis is considered more damaging than Monellia caryella due to later-season peaks that can cause defoliation and reduce nut yield and quality. Management in commercial orchards relies on monitoring, conservation of natural enemies, and selective application. Insecticide resistance has been documented.

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