Phorodon humuli

(Schrank, 1801)

hop aphid, damson-hop aphid

Phorodon humuli is an and the primary pest of cultivated hops (Humulus lupulus). It exhibits a , alternating between Prunus species as winter primary and hop plants as summer secondary hosts. The species causes direct damage through phloem feeding and can reduce hop yields substantially. show cultivar-specific susceptibility patterns and have developed resistance in agricultural settings.

Britannica Economic Entomology 5 by Encyclopædia Britannica, Volume 8, Slice 10., available freely at Project Gutenberg. Used under a Public domain license.

Hop aphid (Phorodon humuli) 5393326 by David Gent, USDA Agricultural Research Service, Bugwood.org. Used under a CC BY 3.0 license.

Circular (1891) (20465042389) by United States. Bureau of Entomology. Used under a No restrictions license.

Pronunciation

How to pronounce Phorodon humuli: //ˌfɔːrəˈdɒn ˈhjuːmjʊlaɪ//

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Identification

Winged migrants () colonize hop plants in spring; forms establish dense colonies on young tissues near bine apices. Smaller body size and specific association with Humulus lupulus distinguishes it from aphids in agricultural settings. Morphological studies document multiple forms with measurable differences between morphs.

Images

Habitat

Agricultural hop gardens and wild hop stands; also Prunus-dominated hedgerows and orchards during winter phase. concentrated on young tissues near bine apices with plant size and wind shelter influencing local distribution patterns.

Distribution

Europe (including Belgium, Germany, UK); recorded from São Miguel (Azores). Agricultural distribution centered in traditional hop-growing regions.

Seasonality

Spring by from Prunus primary to Humulus secondary hosts occurs during June; development continues through summer growing season.

Diet

Phloem sap feeding on Humulus lupulus during summer; Prunus (P. domestica, P. spinosa, P. padus, P. cerasifera) during winter. plant suitability varies significantly between hop cultivars.

Host Associations

Humulus lupulus - secondary (summer)primary agricultural ; cultivar-specific susceptibility documented
Humulus japonicus - secondary (summer)documented summer
Urtica dioica - secondary (summer)documented summer
Prunus domestica - primary (winter) ; site of
Prunus spinosa - primary (winter)
Prunus padus - primary (winter)
Prunus cerasifera - primary (winter)

Life Cycle

Heteroecious with obligate alternation. Sexual phase and production on Prunus primary hosts during winter; fundatrix produces migrants that colonize Humulus secondary hosts in spring. Parthenogenetic continues on hops through summer. Return to Prunus occurs in autumn.

Behavior

migrants do not exhibit trivial between leaves on the primary ; their first flight is directly migratory. On less susceptible hop cultivars, alates display increased motile patterns and reduced settling. Spring migrants show enhanced of plants treated with (Z)-jasmone, contrasting with repellent effects observed in other . Wind shelter and plant architecture strongly influence landing and establishment patterns.

Ecological Role

Agricultural pest causing direct feeding damage to hop ; high can compromise yields. Serves as prey for natural enemy in hop agroecosystems.

Human Relevance

Major economic pest of hop production with documented 80-90% yield loss potential in untreated northeastern U.S. hop yards. Subject of resistance management concerns; associated with elevated esterase activity. Research on resistant hop cultivars (e.g., accession 58016) aims to reduce inputs and protect beneficial insect populations.

Similar Taxa

Phorodon cannabiscongeneric ; primary pest of hemp (Cannabis sativa) rather than Humulus lupulus; similar but distinct specialization
Rhopalosiphum rufiabdominale (rice root aphid)both colonize Cannabis-related crops but R. rufiabdominale is a root-feeding with distribution, whereas P. humuli is a shoot-feeding on Humulus