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Electrical penetration graphs of the damson‐hop aphid, Phorodon humuli on resistant and susceptible hops ( Humulus lupulus )
Author(s) -
Paul Therasa A.,
Darby Peter,
Green Colin P.,
Hodgson Chris J.,
Rossiter John T.
Publication year - 1996
Publication title -
entomologia experimentalis et applicata
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.765
H-Index - 83
eISSN - 1570-7458
pISSN - 0013-8703
DOI - 10.1111/j.1570-7458.1996.tb00946.x
Subject(s) - humulus lupulus , aphididae , biology , phloem , aphid , homoptera , hop (telecommunications) , botany , horticulture , pest analysis , computer network , pepper , computer science
Electrical penetration graphs (EPG's) were used to locate resistance to Phorodon humuli (Schrank) (Homoptera, Aphididae) in hops ( Humulus lupulus , Cannabinaceae). Aphids on those hops showing resistance had a much reduced E2 pattern (uptake of phloem). In addition, many aphids on the resistant plants spent time non‐probing within two minutes of withdrawing from the phloem. This was not observed with aphids on susceptible hops. The results suggest that resistance is located in the phloem. The involvement of a mechanical factor such as the blocking of aphid stylets, the presence of antinutritional factors, or simply an inadequate supply of nutrients, are discussed as possible resistance mechanisms.