Host preference of the brown wheat mite (Petrobia latens [Muller]) in Eastern Colorado

The brown wheat mite, Petrobia latens (Muller), is a common pest of wheat and barley, however it can also infest other non-cultivated grasses.  These pests are native to Eastern Colorado, and have become a problem with an increase in no-till agricultural practices.  The purpose of this study was to quantify host preference, determine adult vagility, and to determine at which life stage host plants are most appealing to P. latens.  Mites were taken from the field and raised in growth chambers on eight cold-season host grasses and six warm-season grasses.  Populations were also sampled from fallow field and field border habitats.  Vagility in adult mites, when presented with less developed hosts, was also studied.  Mites prefer cold-season grasses to warm-season grasses.  Warm season grasses are not traditionally used by the brown wheat mite during its active phase. Petrobia latens has the highest intrinsic rate of increase on alternate hosts such as downy brome and crested wheatgrass as well as the winter wheat TAM107.  Mites also show an increase in population size throughout the season in fallow fields where volunteer wheat is not controlled.  Adult mites also show a high rate of movement from more developed hosts to less developed hosts, suggesting a preference for hosts developing prior to the stem elongation phase, as well as a strong preference for uncolonized hosts.