07-16-14 Field Note

Thistle bio-controls survived the winter! Also, both ring-necked and bufflehead duck broods occupy entrance pond.

Posted on 7/16/2014 by Lorinda Bullington

Habitat Types: 


Field Guide Entries: 

Canada Thistle
Thistle head weevils (Rhinocyllus conicus) inhabit thistle throughout the U.S.
In previous years, we’ve released both the thistle stem-mining weevil (CYPACH) and thistle gall fly (URCA) in high density thistle patches along the property boundary and in riparian areas.
The stem-mining weevil (Ceutorhynchus litura) lays its eggs in the stems of thistle plants.
Once they reach the base of the stem, older larvae exit the plant through small holes (arrows) and enter the soil below.
Galls caused by the thistle gall fly (Urophora cardui) will form from now until September.
Both bufflehead and ring-necked duck broods occupy entrance pond.