Several years ago, we detected and reported the presence of a new aphid in wheat, Metopolophium festucae cerealium, which we are currently calling “Mfc” or “Cereal grass aphid”. A known pest of cereal crops in its native range in the UK, it was initially detected in Oregon in the 1990s but rather suddenly became abundant in Washington state, northern Oregon, and northern Idaho by 2011. It continues to be one of the most abundant aphids in wheat at many locations in the inland Pacific Northwest. Recently, isolated specimens of this pest have been detected in southern Idaho, Montana, and Kansas, suggesting it is spreading. Based on a greenhouse experiment with wheat seedlings, feeding of this pest induces a distinctive chlorotic reaction in wheat and other hosts, presumably causing more per capita injury than by other cereal aphids in the region. Cereal grass aphids established from a clonal colony in the greenhouse was unable to transmit Barley yellow dwarf virus. However, other genotypes of this aphid with other strains and isolates of Barley yellow dwarf virus may result in transmission, which requires further studies. In other words, Cereal grass aphid is persisting in our systems and may be spreading so we should pursue additional research to establish whether it is a virus vector and to build appropriate decision support tools for its management.
Figure 1.
Meanwhile, growers should be vigilant for the pest in their wheat fields. The characteristic feeding damage occurring with groups of pale green aphids as shown in Fig. 1 indicates a likely infestation. If you see those signs in either spring or winter wheat this season, please let us know. There is as yet no threshold, but based on one greenhouse trial its effects on plant growth are greater than most other aphids in our system.
