Lewis & Short

2. suffītus, ūs, m. [suffio].

  1. I. A fumigating, fumigation (Plinian): suffitu necare cimices, Plin. 32, 10, 42, § 142; 37, 10, 54, § 142: crebrior, id. 22, 23, 48, § 100.
    Plur., Plin. 24, 11, 61, § 102.
  2. II. In concr., the smoke produced by fumigation: herbae, Plin. 21, 18, 69, § 116.