Editing Biological pest control (section)

===Pathogens===
{{Further|Biopesticide}}

Pathogenic micro-organisms include [[bacteria]], [[fungi]], and [[viruses]]. They kill or debilitate their host and are relatively host-specific. Various [[microbial]] insect diseases occur naturally, but may also be used as [[biological pesticide]]s.<ref>[http://ec.europa.eu/environment/integration/research/newsalert/pdf/134na5.pdf Encouraging innovation in biopesticide development.] {{webarchive |url=https://web.archive.org/web/20120515143828/http://ec.europa.eu/environment/integration/research/newsalert/pdf/134na5.pdf |date=15 May 2012}} European Commission (2008). Accessed on 9 January 2017</ref> When naturally occurring, these outbreaks are density-dependent in that they generally only occur as insect populations become denser.<ref>{{cite book |author1=Huffaker, C. B. |author2=Berryman, A. A. |author3=Laing, J. E. |date=1984 |chapter=Natural control of insect populations |pages=[https://archive.org/details/ecologicalentomo0000unse/page/359 359–398] |editor=C. B. Huffaker and R. L. Rabb |title=Ecological Entomology |publisher=Wiley Interscience |isbn=978-0-471-06493-0 |chapter-url=https://archive.org/details/ecologicalentomo0000unse |url=https://archive.org/details/ecologicalentomo0000unse/page/359 }}</ref>

The use of pathogens against [[aquatic weed]]s was unknown until a groundbreaking 1972 proposal by Zettler and Freeman. Up to that point biocontrol of any kind had not been used against any water weeds. In their review of the possibilities, they noted the lack of interest and information thus far, and listed what was known of pests-of-pests – whether pathogens or not. They proposed that this should be relatively straightforward to apply in the same way as other biocontrols.<ref name="Zettler-Freeman-1972">{{cite journal | last1=Zettler | first1=F W | last2=Freeman | first2=T E | title=Plant Pathogens as Biocontrols of Aquatic Weeds | journal=[[Annual Review of Phytopathology]] | publisher=[[Annual Reviews (publisher)|Annual Reviews]] | volume=10 | issue=1 | year=1972 | issn=0066-4286 | doi=10.1146/annurev.py.10.090172.002323 | pages=455–470| bibcode=1972AnRvP..10..455Z }}</ref> And indeed in the decades since, the same biocontrol methods that are routine on land have become common in the water.

====Bacteria====

Bacteria used for biological control infect insects via their digestive tracts, so they offer only limited options for controlling insects with sucking mouth parts such as aphids and scale insects.<ref>{{cite book |author=Swan, L.A. |date=1964 |title=Beneficial Insects |url=https://archive.org/details/beneficialinsect0000swan |url-access=registration |page= [https://archive.org/details/beneficialinsect0000swan/page/249 249]|publisher=New York, Harper & Row }}</ref> ''[[Bacillus thuringiensis]]'', a soil-dwelling bacterium, is the most widely applied species of bacteria used for biological control, with at least four sub-species used against [[Lepidoptera]]n ([[moth]], [[butterfly]]), [[Coleoptera]]n (beetle) and [[Diptera]]n (true fly) insect pests. The bacterium is available to organic farmers in sachets of dried spores which are mixed with water and sprayed onto vulnerable plants such as [[brassica]]s and [[fruit tree]]s.<ref name=Lemaux>{{cite journal |doi=10.1146/annurev.arplant.58.032806.103840 |title=Genetically Engineered Plants and Foods: A Scientist's Analysis of the Issues (Part I) |year=2008 |last1=Lemaux |first1=Peggy G. |journal=Annual Review of Plant Biology |volume=59 |issue=1 |pages=771–812 |pmid=18284373|bibcode=2008AnRPB..59..771L }}</ref><ref name=McGaughey>{{cite journal | last1 = McGaughey | first1 = W. H. | last2 = Gould | first2 = F. | last3 = Gelernter | first3 = W. | year = 1998 | title = Bt resistance management | journal = Nat. Biotechnol. | volume = 16 | issue = 2| pages = 144–6 | doi = 10.1038/nbt0298-144 | pmid = 9487517 | s2cid = 37947689 }}</ref> [[Gene]]s from ''B. thuringiensis'' have also been incorporated into [[Genetically modified crops|transgenic crops]], making the plants express some of the bacterium's toxins, which are [[protein]]s. These confer resistance to insect pests and thus reduce the necessity for pesticide use.<ref name=Kumar>{{Cite book| last1=Kumar | first1=PA | last2=Malik | first2=VS | last3=Sharma | first3=RP | year=1996 | title=Insecticidal proteins of Bacillus thuringiensis | journal=Advances in Applied Microbiology | volume=42 | pages=1–43 | doi=10.1016/S0065-2164(08)70371-X | pmid=8865583 | isbn=9780120026425  | url=https://zenodo.org/record/1259743 }}</ref> If pests develop resistance to the toxins in these crops, ''B. thuringiensis'' will become useless in organic farming also.<ref>{{cite web|last1=Neppl |first1=Camilla |title=Management of Resistance to Bacillus thuringiensis Toxins |url=http://camillapede.tripod.com/bapaper.html |date=26 May 2000 |url-status=live |archive-url=https://web.archive.org/web/20170421000124/http://camillapede.tripod.com/bapaper.html |archive-date=21 April 2017 }}</ref><ref name=McGaughey/>
The bacterium ''[[Paenibacillus popilliae]]'' which causes [[Milky spore|milky spore disease]] has been found useful in the control of [[Japanese beetle]], killing the larvae. It is very specific to its host species and is harmless to vertebrates and other invertebrates.<ref>{{cite web|url=http://www.biocontrol.entomology.cornell.edu/pathogens/paenibacillus.php |title=Biological control: ''Paenibacillus popilliae'' |publisher=Cornell University |access-date=15 June 2016 |url-status=dead |archive-url=https://web.archive.org/web/20160621024151/http://www.biocontrol.entomology.cornell.edu/pathogens/paenibacillus.php |archive-date=21 June 2016 }}</ref>

''[[Bacillus]]'' spp.,<ref group="M" name="biocontrol-MoAs">p.{{nbs}}94-5, II. Biocontrol Modes of Action</ref> [[fluorescent Pseudomonad]]s,<ref group="M" name="biocontrol-MoAs" /> and [[Streptomycete]]s are controls of various fungal pathogens.<ref group="M" name="intro-examples-agents">p.{{nbs}}94</ref>

==== Colombia mosquito control ====
The largest-ever deployment of ''[[Wolbachia]]''-infected ''A. aegypti'' mosquitoes reduced dengue incidence by 94–97% in the Colombian cities of [[Bello, Antioquia|Bello]], [[Medellín]], and [[Itagüí]]. The project was executed by non-profit World Mosquito Program (WMP). Wolbachia prevents mosquitos from transmitting viruses such as dengue and [[zika]]. The insects pass the bacteria on to their offspring. The project covered a combined area of {{Convert|135|km2}}, home to 3.3 million people. Most of the project area reached the target of infecting 60% of local mosquitoes. The technique is not endorsed by WHO.<ref>{{Cite journal |last=Lenharo |first=Mariana |date=2023-10-27 |title=Dengue rates drop after release of modified mosquitoes in Colombia |url=https://www.nature.com/articles/d41586-023-03346-2 |journal=Nature |volume=623 |issue=7986 |pages=235–236 |language=en |doi=10.1038/d41586-023-03346-2|pmid=37891252 |bibcode=2023Natur.623..235L |s2cid=264543032 }}</ref>