Plant bug (Zo["o]l.), any one of numerous hemipterous insects which injure the foliage of plants, as Lygus lineolaris, which damages wheat and trees.

Plant cutter (Zo["o]l.), a South American passerine bird of the genus Phytotoma, family Phytotomid[ae]. It has a serrated bill with which it cuts off the young shoots and buds of plants, often doing much injury.

Plant louse (Zo["o]l.), any small hemipterous insect which infests plants, especially those of the families Aphid[ae] and Psyllid[ae]; an aphid.

Source: Webster's Revised Unabridged Dictionary (1913)