Definition of frass in US English:



  • 1Fine powdery refuse or fragile perforated wood produced by the activity of boring insects.

    • ‘By the end of the experiment, an average of 25% of the cotyledon of Q. alba acorns had been reduced to frass, while there was no apparent damage in any of the final sample of RO acorns.’
    • ‘We felt the fine, sharply scented frass of a carpenter ant colony with our fingertips.’
    1. 1.1 The excrement of insect larvae.
      • ‘This frass is considerably different from the pelletized frass left by drywood and dampwood termites.’
      • ‘One downside of group dining is that chemical signals from the larvae and their frass can attract parasitoids.’
      • ‘The chemical analyses of the body and frass of Blepharida flavocostata revealed almost no match to the constituents found in B. biflora.’
      • ‘After collecting, we removed litter from litter bags and gently cleaned it of roots, invertebrates, frass, and soil.’
      • ‘Thus removal of cues for natural enemies is likely to have been an important selective force in the evolution of frass ejection behavior in shelter-dwelling larvae.’
      • ‘As larvae feed, they spin silken threads, trapping the dying florets and their frass, giving the sunflower head a trashy appearance.’
      • ‘As a bit of frass starts to emerge from the caterpillar, it pushes a hinged plate against a ring of blood vessels surrounding the anus.’
      • ‘Larvae that had consumed leaf material frequently had green coloured alimentary canals, green frass and a portion of the leaf surface was scarred.’
      • ‘Keep the grass mowed or mulched around the trunks of your fruit trees and watch for the telltale rusty frass of borers - these larval worms can be dug out with a sturdy wire.’
      • ‘I measured digestibility as the proportion of eaten plant biomass not deposited as frass by 0800 the following morning.’
      • ‘Often dark black pellets of frass will be in the nest with the caterpillar.’
      • ‘They seemed to hunt by scent, ignoring nests with faux frass in the form of small black glass beads.’
      • ‘The notion that Tunisian blue-striped caterpillar frass could help you burn fat overnight while you sleep, strengthen muscles without exercise, erase wrinkles and improve your memory is too tempting for some folks to resist.’
      • ‘On closer inspection, obvious discolored wounds can often be seen at the base of the plant and stems, and at the wounds, masses of a yellow-green grainy substance known as frass - the hygienic German word for caterpillar excrement.’
      • ‘Identifying the presence of frass coupled with damage is a strong indication of the presence of a caterpillar, or in some cases, beetle larvae.’


Mid 19th century: from German Frass, from fressen ‘devour’.