Tetrastichus is a genus of hymenopteran insects of the family Eulophidae.

Tetrastichus planipennisi is a parasitoid of the emerald ash borer, a wood boring insect native to Asia which is an invasive species in North America.

Tetrastichus setifer is a paraditoid of the scarlet lily beetle. The beetle is invasive in North America, and highly destructive to lily species; the wasp has been introduced there for biological pest control.

Tetrastichus coeruleus can be used as a biological control agent for the common asparagus beetle.

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