Cereal leaf beetle larvae have been observed in some small grain fields, especially wheat fields in southeastern Pennsylvania, according to a May 12 report. Oats fields are also known to harbor this pest species.
The presence of cereal leaf beetle larvae is difficult to predict and often varies within and between fields, making scouting an important tool for farmers. The article explains that eggs and young larvae are orange and relatively easy to see, but older larvae can be mistaken for slugs because they appear dark and shiny due to being covered with their own frass. A distinguishing feature is the presence of six small legs on the larvae; slugs do not have legs and are typically active at night, while cereal leaf beetle larvae can be seen during the day.
“If you look closely at these shiny animals and see six small legs, you will know you are dealing with cereal leaf beetle larvae and not slugs,” the report says. It also notes that larger cereal leaf beetle larvae cause more damage, particularly when feeding on the flag leaf of wheat plants.
Insecticide treatments may be necessary if populations exceed one larva greater than one-eighth-inch long per stem across a field or part of a field. “If young larvae are detected at populations exceeding the economic threshold, cereal leaf beetle is easily controlled with insecticides, but larger larvae are more difficult to control and cause more damage,” the report says.
Farmers seeking additional information about lifecycle details or management options can consult Penn State’s Agronomy Guide or a recently revised fact sheet with images of adults, larvae, and their damage. Penn State Extension provides science-based education promoting agriculture as well as workshops on farming practices such as pest control through its local offices across Pennsylvania and digital tools online,according to Penn State Extension.
