Entomological warfare (EW) is a type of biological warfare that uses insects to attack the enemy. The concept has existed for centuries and research and development have continued into the modern era. EW has been used in battle by Japan and several other nations have developed and been accused of using an entomological warfare program.
Entomological warfare (EW) is a specific type of biological warfare (BW)  that uses insects in a direct attack or as vectors to deliver a biological agent, such as plague or cholera. Essentially, EW exists in three varieties.  One type of EW involves infecting insects with a pathogen and then dispersing the insects over target areas.  The insects then act as a vector, infecting any person or animal they might bite. Another type of EW is a direct insect attack against crops; the insect may not be infected with any pathogen but instead represents a threat to agriculture.  The final method of entomological warfare is to use uninfected insects, such as bees, to directly attack the enemy. 
Entomological warfare is not a new concept; historians and writers have studied EW in connection to multiple historic events. A 14th century plague epidemic in Asia Minor that eventually became known as the Black Death (carried by fleas) is one such event that has drawn attention from historians as a possible early incident of entomological warfare.  That plague's spread over Europe may have been the result of a biological attack on the Crimean city of Kaffa. 
According to Jeffrey Lockwood, author of Six-Legged Soldiers (a book about EW), the earliest incident of entomological warfare was probably the use of bees by early humans.  The bees or their nests were thrown into caves to force the enemy out and into the open.  Lockwood theorizes that the Ark of the Covenant may have been deadly when opened because it contained deadly fleas.  
During the American Civil War the Confederacy accused the Union of purposely introducing the harlequin bug in the South.  These accusations were never proven, and modern research has shown it more likely that the insect arrived by other means.  The world did not experience large-scale entomological warfare until World War II; Japanese attacks in China were the only verified instance of BW or EW during the war.  During, and following, the war other nations began their own EW programs.
France is known to have pursued entomological warfare programs during World War II.  Like Germany, the nation suggested that the Colorado potato beetle, aimed at the enemy's food sources, would be an asset during the war.  As early as 1939 biological warfare experts in France suggested that the beetle be used against German crops. 
Germany is known to have pursued entomological warfare programs during World War II.  The nation pursued the mass-production, and dispersion, of the Colorado potato beetle (Lepinotarsa decemlineata), aimed at the enemy's food sources.  The beetle was first found in Germany in 1914, as an invasive species from North America.  There are no records that indicate the beetle was ever employed as a weapon by Germany, or any other nation during the war.  Regardless, the Germans had developed plans to drop the beetles on English crops. 
Germany carried out testing of its Colorado potato beetle weaponization program south of Frankfurt, where they released 54,000 of the beetles.  In 1944, an infestation of Colorado potato beetles was reported in Germany.  The source of the infestation is unknown, speculation has offered three alternative theories as to the origin of the infestation. One option is Allied action, an entomological attack, another is that it was the result of the German testing, and still another more likely explanation is that it was merely a natural occurrence. 
Among the Allied Powers, Canada led the pioneering effort in vector-borne warfare.  After Japan became intent on developing the plague flea as a weapon, Canada and the United States followed suit.  Cooperating closely with the United States, Dr. G.B. Reed, chief of Kingston's Queen's University's Defense Research Laboratory, focused his research efforts on mosquito vectors, biting flies, and plague infected fleas during World War II.  Much of this research was shared with or conducted in concert with the United States. 
Canada's entire bio-weapons program was ahead of the British and the Americans during the war.  The Canadians tended to work in areas their allies ignored; entomological warfare was one of these areas.  As the U.S. and British programs evolved, the Canadians worked closely with both nations. The Canadian BW work would continue well after the war,  including entomological research. 
Japan used entomological warfare on a large scale during World War II in China.  Unit 731, Japan's infamous biological warfare unit led by Lt. General Shirō Ishii, used plague-infected fleas and flies covered with cholera to infect the population in China.  The Japanese military dispersed the insects by spraying them from low-flying airplanes and dropping bombs filled with a mixture of insects and disease.  Localized and deadly epidemics resulted and nearly 500,000 Chinese died of disease.   An international symposium of historians declared in 2002 that Japanese entomological warfare in China was responsible for the deaths of 440,000. 
The late Ban Shigeo, a technician at the Japanese Army's 9th Technical Research Institute, left a rare and valuable account of the activities of Noborito Research Institute, which was published in Rikugun Noborito Kenkyujo no shinjitsu – The Truth About the Army Nororito Institute (available only in the Japanese language). Of the Japanese Army's ten numbered institutes, only the 9th Army Technical Research Institute came under the covert operations section of the Army General Staff's Second Bureau (Intelligence). On the sensitive issue of Japanese biological warfare, Ban did not shrink from including an account of his trip to Nanking in 1941 to participate in the testing of poisons on Chinese prisoners. One of his book's contributions is to further tie Noborito to the Japanese Army's infamous Unit 731, which participated in biomedical research. When the war ended, the US Army quietly enlisted certain members of Noborito in its efforts against the communist camp in the early years of the Cold War. The author notes near the end of the book that Ban led the "chemical section" of a US clandestine unit hidden within Yokosuka naval base during the Korean War, and then worked on unspecified projects inside the United States from 1955 to 1959, before returning to Japan to enter the private sector.  Shirō Ishii of Unit 731, having not been charged as a war criminal, also continued his work to consult with American authorities, especially during the height of the Cold War, and died in 1959 of throat cancer. 
In 1989, a British study of Unit 731 strongly supported the theory of United States-Japanese BW culpability in Korea. Chinese experts insist today that BW weapons created in an American-Japanese collaboration were used in the Korean war. 
A British scientist, J.B.S. Haldane, suggested that Britain and Germany were both vulnerable to entomological attack via the Colorado potato beetle.  In 1942 the United States shipped 15,000 Colorado potato beetles to Britain for study as a weapon. 
The Soviet Union researched, developed and tested an entomological warfare program as a major part of an anti-crop and anti-animal BW program. The Soviets developed techniques for using insects to transmit animal pathogens, such as foot and mouth disease—which they used ticks to transmit. The nation also used avian ticks to transmit Chlamydophila psittaci to chickens. In addition, the Soviet Union claimed to have developed an automated mass insect breeding facility, capable of outputting millions of parasitic insects per day. 
The United States seriously researched the potential of entomological warfare during the Cold War. The United States military developed plans for an entomological warfare facility, designed to produce 100 million yellow fever-infected mosquitoes per month.  A U.S. Army report  titled "Entomological Warfare Target Analysis" listed vulnerable sites within the Soviet Union that the U.S. could attack using entomological vectors.  The military also tested the mosquito biting capacity by dropping uninfected mosquitoes over U.S. cities. 
North Korean and Chinese officials leveled accusations that during the Korean War the United States engaged in biological warfare, including EW, in North Korea. The claim is dated to the period of the war, and has been thoroughly denied by the U.S.  In 1998, Stephen Endicott and Edward Hagermann claimed that the accusations were true in their book, The United States and Biological Warfare: Secrets from the Early Cold War and Korea  The book received mixed reviews, some called it "bad history"  and "appalling",  while other praised the case the authors made.  Other historians have revived the claim in recent decades as well.  The same year Endicotts' book was published Kathryn Weathersby and Milton Leitenberg of the Cold War International History Project at the Woodrow Wilson Center in Washington released a cache of Soviet and Chinese documents which revealed the North Korean claim was an elaborate disinformation campaign. 
During the 1950s the United States conducted a series of field tests using entomological weapons. Operation Big Itch, in 1954, was designed to test munitions loaded with uninfected fleas ( Xenopsylla cheopis).  Big Itch went awry when some of the fleas escaped into the plane and bit all three members of the air crew.  In May 1955 over 300,000 uninfected mosquitoes ( Aedes aegypti) were dropped over parts of the U.S. state of Georgia to determine if the air-dropped mosquitoes could survive to take meals from humans.  The mosquito tests were known as Operation Big Buzz.  Operation Magic Sword was a 1965 U.S. military operation designed to test the effectiveness of the sea-borne release of insect vectors for biological agents. The U.S. engaged in at least two other EW testing programs, Operation Drop Kick and Operation May Day.  A 1981 Army report outlined these tests as well as multiple cost-associated issues that occurred with EW.  The report is partially declassified—some information is blacked out, including everything concerning "Drop Kick" —and included "cost per death" calculations.  The cost per death, according to the report, for a vector-borne biological agent achieving a 50% mortality rate in an attack on a city was $0.29 in 1976 dollars.  Such an attack was estimated to result in 625,000 deaths. 
At Kadena Air Force Base, an Entomology Branch of the U.S. Army Preventive Medicine Activity, U.S. Army Medical Center was used to grow "medically important" arthropods, including many strains of mosquitoes in a study of disease vector efficiency.  The program reportedly supported a research program studying taxonomic and ecological data surveys for the Smithsonian Institution."  The Smithsonian Institution and The National Academy of Sciences and National Research Council administered special research projects in the Pacific.  The Far East Section of the Office of the Foreign Secretary administered two such projects which focused "on the flora of Okinawa" and "trapping of airborne insects and arthropods for the study of the natural dispersal of insects and arthropods over the ocean." :59 The motivation for civilian research programs of this nature was questioned when it was learned that such international research was in fact funded by and provided to the U.S. Army as requirement related to the U.S. military's biological warfare research.  
The United States has also applied entomological warfare research and tactics in non-combat situations. In 1990 the U.S. funded a $6.5 million program designed to research, breed and drop caterpillars.  The caterpillars were to be dropped in Peru on coca fields as part of the American War on Drugs.  As recently as 2002 U.S. entomological anti-drug efforts at Fort Detrick were focused on finding an insect vector for a virus that affects the opium poppy. 
Clemson University's Regulatory and Public Service Program listed "diseases vectored by insects" among bioterrorism scenarios considered "most likely".  Because invasive species are already a problem worldwide one University of Nebraska entomologist considered it likely that the source of any sudden appearance of a new agricultural pest would be difficult, if not impossible, to determine.  Lockwood considers insects a more effective means of transmitting biological agents for acts of bioterrorism than the actual agents.  Insect vectors are easily gathered and their eggs easily transportable without detection.  Isolating and delivering biological agents, on the other hand, is extremely challenging and hazardous. 
In one of the few suspected acts of entomological bioterrorism an eco-terror group known as The Breeders claimed to have released Mediterranean fruit flies (medflies) amidst an ongoing California infestation.  Lockwood asserts that there is some evidence the group played a role in the event.  The pest attacks a variety of crops and the state of California responded with a large-scale pesticide spraying program.  At least one source asserted that there is no doubt that an outside hand played a role in the dense 1989 infestation.  The group stated in a letter to then Los Angeles Mayor Tom Bradley that their goals were twofold.  They sought to cause the medfly infestation to grow out of control which, in turn, would render the ongoing malathion spraying program financially infeasible. 
The Biological and Toxic Weapons Convention (BWC) of 1972 does not specifically mention insect vectors in its text.  The language of the treaty, however, does cover vectors.  Article I bans "Weapons, equipment or means of delivery designed to use such agents or toxins for hostile purposes or in armed conflict."   It would appear, due to the text of the BWC, that insect vectors as an aspect of entomological warfare are covered and outlawed by the Convention.  The issue is less clear when warfare with uninfected insects against crops is considered. 
This section needs expansion. You can help by adding to it. (January 2017)
- 1989 California medfly attack
- War against the potato beetle
- Military animal
- Brain implant § Research and applications
- Peterson, R.K.D. " The Role of Insects as a Biological Weapon Archived 2008-07-05 at the Wayback Machine.", Department of Entomology, Montana State University, notes based on seminar, 1990, accessed December 25, 2008.
- Lockwood, Jeffrey A. Six-legged Soldiers: Using Insects as Weapons of War, Oxford University Press, USA, 2008, pp. 9–26, ( ISBN 0195333055).
- " An Introduction to Biological Weapons, Their Prohibition, and the Relationship to Biosafety Archived 2013-05-12 at the Wayback Machine.", The Sunshine Project, April 2002, accessed December 25, 2008.
- Kirby, Reid. " Using the flea as weapon", ( Web version via findarticles.com), Army Chemical Review, July 2005, accessed December 23, 2008.
- Baumann, Peter. " Warfare gets the creepy-crawlies", Laramie Boomerang, October 18, 2008, accessed December 23, 2008.
- " UW Professor Examines Biological Setting of Egyptian Plagues", ( Press release), University of Wyoming, December 12, 2005, accessed December 23, 2008.
- Lockwood, Jeffrey A. " Bug Bomb", Boston Globe, October 21, 2007, accessed December 23, 2008.
- Croddy, Eric and Wirtz, James J. Weapons of Mass Destruction: An Encyclopedia of Worldwide Policy, Technology, and History, ( Google Books), ABC-CLIO, 2005, p. 304, ( ISBN 1851094903).
- Heather, Neil W. and Hallman, Guy J. Pest Management and Phytosanitary Trade Barriers ([Google Books]), CABI, 2008, pp. 17–18, ( ISBN 1845933435).
- Baker, Eric. " 'Maggot bombs' and malaria", Casper Star-Tribune, via the Laramie Boomerang, February 27, 2006, accessed December 25, 2008.
- Endicott, Stephen, and Hagermann, Edward. The United States and Biological Warfare: Secrets from the Early Cold War and Korea, ( Google Books, relevant excerpt), Indiana University Press, 1998, pp. 75-77, ( ISBN 0253334721), links accessed December 24, 2008.
- Wheelis, Mark, et al. Deadly Cultures: Biological Weapons Since 1945, ( Google Books), Harvard University Press, 2006, pp. 84-90, ( ISBN 0674016998).
- Lockwood, Jeffrey A. " Six-legged soldiers", The Scientist, October 24, 2008, accessed December 23, 2008.
- Novick, Lloyd and Marr, John S. Public Health Issues Disaster Preparedness, ( Google Books), Jones & Bartlett Publishers, 2001, p. 87, ( ISBN 0763725005).
- CIA review of "Rikugun Noborito Kenkyujo no shinjitsu [The Truth About the Army Noborito Research Institute]" By Ban Shigeo. Tokyo: Fuyo Shobo Shuppan, 2001: https://www.cia.gov/library/center-for-the-study-of-intelligence/csi-publications/csi-studies/studies/vol46no4/article11.html
- THE ROLE OF INSECTS AS BIOLOGICAL WEAPONS notes for a seminar presented by R.K.D. Peterson in 1990 at the University of Nebraska. Retrieved July 20, 2012: "Archived copy". Archived from the original on 2008-07-05. Retrieved 2008-12-25.
- Factories of Death Japanese biological warfare 1932–45 and the American cover-up by Sheldon H. Harris: https://www.scribd.com/doc/91284707/Factories-of-Death
- Ban, Jonathan. " Agricultural Biological Warfare: An Overview Archived 2001-09-20 at the Wayback Machine.", The Arena, June 2000, Paper #9, Chemical and Biological Arms Control Institute, via Memorial Institute for the Prevention of Terrorism, accessed December 25, 2008. Archived 2001-09-20 at the Wayback Machine.
- Regis, Ed. " Wartime Lies?", The New York Times, June 27, 1999, accessed December 24, 2008.
- " Reviews of The United States and Biological Warfare: secrets of the Early Cold War and Korea", York University, compiled book review excerpts, accessed December 24, 2008.
- Auster, Bruce B. " Unmasking an Old Lie Archived 2011-05-24 at the Wayback Machine.", U.S. News and World Report, November 16, 1998, accessed December 24, 2008.
- Rose, William H. " An Evaluation of Entomological Warfare as a Potential Danger to the United States and European NATO Nations", U.S. Army Test and Evaluation Command, Dugway Proving Ground, March 1981, via thesmokinggun.com, accessed December 25, 2008.
- "Bugs keep Group Humming at Kadena". Pacific Stars and Stripes. August 2, 1968.
- National Academy of Sciences (U.S.) (1966). International Activities of the National Academy of Sciences-National Research Council, 1964/1965. National Academies. pp. 59–. NAP:11015. Retrieved April 17, 2013. This article incorporates text from this source, which is in the public domain.
- Moynihan (July 29, 1974). "Indian press articles on W.H.O. Biogenetic Mosquito control Project and Migratory Bird Project, Document Number: 1974NEWDE10039". US Department of State EO Systematic Review, US Department of State. US Department of State via NARA. Archived from the original on June 16, 2013. Retrieved April 14, 2013. This article incorporates text from this source, which is in the public domain.
- Powell, Kendall; Jayaraman, K. S. (2002). "Mosquito Researchers Deny Plotting Secret Biowarfare Test". Nature. 419 (6910): 867–867. doi: 10.1038/419867a.
- Irwin, M.E. and G.E. Kampmeier. " Commercial products, from insects", (p. 6). In Resh, V.H. & Carde, R. eds. Encyclopedia of Insects, Academic Press, San Diego, via University of Illinois and Illinois Natural History Survey, accessed December 25, 2008.
- " Regulatory and Public Service Programs’ Strategy for the Prevention Of Bioterrorism in Areas Regulated Archived 2009-01-17 at the Wayback Machine.", Regulatory and Public Service Program, Clemson University, 2001, accessed December 25, 2008.
- Corley, Heather. " Agricultural Bioterror Threat Requires Vigilance Archived 2012-02-18 at the Wayback Machine.", ( Press release), Institute of Agriculture and Natural Resource, University of Nebraska, November 12, 2001, accessed December 25, 2008.
- Lockwood, Jeffrey A. " Insects: Tougher than anthrax", The Boston Globe, October 21, 2007, accessed December 25, 2008.
- Bonfante, Jordan. " Medfly Madness", Time Magazine, January 8, 1990, accessed December 25, 2008.
- Howard, Russell D. et al. Homeland Security and Terrorism: Readings and Interpretations, ( Google Books), McGraw-Hill Professional, 2006, p. 49, ( ISBN 0071452826).
- Sims, Nicholas Roger Alan, ( Stockholm International Peace Research Institute). The Evolution of Biological Disarmament, ( Google Books), Oxford University Press, 2001, pp. 45-50, ( ISBN 0198295782).
- " Convention on the Prohibition of the Development, Production and Stockpiling of Bacteriological (Biological) and Toxin Weapons and on Their Destruction", The Biological and Toxic Weapons Convention Website, accessed January 5, 2009.
- Zanders, Jean Pascal. " Research Policies, BW Development & Disarmament Archived 2008-10-06 at the Wayback Machine.", Conference: "Ethical Implications of Scientific Research on Bioweapons and Prevention of Bioterrorism", European Commission, via BioWeapons Prevention Project, February 4, 2004, accessed January 5, 2009.
- Regalado, Antonio. "Top U.S. Intelligence Official Calls Gene Editing a WMD Threat". MIT Technology Review. Retrieved 26 December 2016.
- Bryden, John. Deadly Allies: Canada's Secret War, 1937-1947, ( Google Books), McClelland & Stewart, 1989, ( ISBN 0771017243).
- Garrett, Benjamin C. " The Colorado Potato Beetle Goes to War", Chemical Weapons Convention Bulletin, Issue #33, September 1996, accessed January 3, 2009.
- Hay, Alastair. "A Magic Sword or A Big Itch: An Historical Look at the United States Biological Weapon Programme", ( Citation), Medicine, Conflict, and Survival, Vol. 15 July–September 1999, pp. 215–234).
- Lockwood, Jeffrey A. "Entomological Warfare: History of the Use of Insects as Weapons of War" ( Citation, Bulletin of the Entomological Society of America, Summer 1987, v. 33(2), pp. 76–82.
- Lockwood, Jeffrey A. " The Scary Caterpillar", The New York Times, April 18, 2009, accessed April 24, 2009.
- Lockwood, J. A. (2012). "Insects as Weapons of War, Terror, and Torture". Annual Review of Entomology. 57: 205–227. doi: 10.1146/annurev-ento-120710-100618. PMID 21910635.