The EIL may differ with regards to the particular pest, crop, and region. It signifies the point at which intervention is critical to stop economic losses. The 11th-century Aged English healthcare text Lacnunga contained charms and spells to thrust back or deal with pests including wid smeogan wyrme, "penetrating worms", https://bookmarkforest.com/story19863561/detailed-notes-on-pest-crm