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Nanophyes marmoratus
Biological agent type
seed weevil.
Plant species attacked
purple loosestrife (Lythrum salicaria)
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Nanophyes marmoratus adult
host damage
Images by Eric Coombs, Oregon Department of Agriculture.

If images are downloaded and used from the ODA web site please be sure to credit the photographer.
Site of attack
Unopened flower buds by larvae and developing leaves by adults.
Mode of attack
Larvae feed in the seed capsules, consuming many of the developing seeds.
Destructive stage
Larval and adult.
Collection and release information
Widespread in distribution and can be collected by sweep net or beating sheet June-July. Consult with ODA for availability for your area.
History in Oregon
In 1994, the seed weevil Nanophyes marmoratus was released in several counties in Oregon. Adult weevils were recovered at all release sites and limited redistribution began in 1997. In 1999, the weevil became collectible in Malheur County and have since been distributed to many other infestations throughout the state. This weevil may be most effective in areas where the Galerucella beetles have little impact, especially at sites with scattered plants and low plant densities.
Release status in Oregon
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distribution map