Entomological warfare

Entomological warfare includes both the use of insects (and other arthropods) as biological weapons. The more common use is the insects being used as the carrier for vector-borne diseases. There have been, however, suggestions and reports of direct use of the insects to produce harmful effects, particularly against agricultural targets.

During the American Civil War, the Confederacy alleged that the Unionon introduced the harlequin bug, Murgentia histrionica, into the South. "Tremendous crop damage resulted in the South because of this pest. This allegation was never proven and it now appears that the harlequin bug moved on its own into the South from Mexico. However, humans may have aided in the movement of this pest." Modern experience with the challenges of producing, transporting and delivering large numbers of insects throw doubt on the allegation.

The early Japanese biological warfare program at Unit 731 emphasized vector-borne diseases, including both free fleas and parachuted flea-infested rats to spread fleas containing Yersinia pestis, the pathogen of plague. While they later moved to the aerosol methods used by Britain, the Soviet Union, and United States, they did not abandon the approach.

Nazi Germany had much smaller research program than the other countries, but did explore "using insects such as the Colorado potato beetle to attack Allied potato crops. The Germans were accused of dropping cardboard boxes filled with Colorado potato beetles over England from 1941-1943. The containers were never recovered but abnormalities associated with the presence of the beetles prompted Sir Maurice Hankey, head of Britain's BW effort, to write a memo to Winston Churchill with his concerns."