Impact scoring system (1–9) established by the HIWG for non-native, phytophagous insects, where 1 indicates no damage and 9 indicates severe damage (also found in Mech et al. 2019a).

 
 
  Part of: Schulz AN, Mech AM, Allen CR, Ayres MP, Gandhi KJK, Gurevitch J, Havill NP, Herms DA, Hufbauer RA, Liebhold AM, Raffa KF, Raupp MJ, Thomas KA, Tobin PC, Marsico TD (2020) The impact is in the details: evaluating a standardized protocol and scale for determining non-native insect impact. NeoBiota 55: 61-83. https://doi.org/10.3897/neobiota.55.38981