Editing Rice (section)

=== Pest management ===

{{further|Integrated pest management|rice-duck farming}}

[[Crop protection]] scientists are developing [[Sustainable agriculture|sustainable]] techniques for managing rice pests.<ref name="Jahn Khiev Pol 2001">{{cite book |last1=Jahn |first1=Gary C. |author2=Khiev, B.  |author3=Pol, C. |author4=Chhorn, N. |author5=Pheng, S. |author6=Preap, V. |date=2001 |chapter=Developing sustainable pest management for rice in Cambodia |pages=243–258 |editor1=Suthipradit, S. |editor2=Kuntha, C. |editor3=Lorlowhakarn, S. |editor4=Rakngan, J. |title=Sustainable Agriculture: Possibility and Direction |location=Bangkok (Thailand) |publisher=National Science and Technology Development Agency }}</ref> Sustainable pest management is based on four principles: biodiversity, host plant resistance, landscape ecology, and hierarchies in a landscape—from biological to social.<ref name="Savary Horgan Willocquet 2012">{{cite journal |last1=Savary |first1=S. |last2=Horgan |first2=F. |last3=Willocquet |first3=L. |last4=Heong |title=A review of principles for sustainable pest management in rice |year=2012 |journal=[[Crop Protection (journal)|Crop Protection]] |volume=32 |page=54 |doi=10.1016/j.cropro.2011.10.012|bibcode=2012CrPro..32...54S }}</ref> Farmers' pesticide applications are often unnecessary.<ref>{{cite web |url=http://www.scidev.net/Features/index.cfm?fuseaction=readfeatures&itemid=306&language=1 |title=Bangladeshi farmers banish insecticides |work=SCIDEV.net |date=July 30, 2004 |access-date=May 13, 2012 |url-status=dead |archive-url=https://web.archive.org/web/20080126115934/http://www.scidev.net/Features/index.cfm?fuseaction=readfeatures&itemid=306&language=1 |archive-date=January 26, 2008 }}</ref> Pesticides may actually induce [[resurgence (pest)|resurgence]] of populations of rice pests such as the [[brown planthopper]], both by destroying beneficial insects and by enhancing the pest's reproduction.<ref name="Wu Ge Liu Song 2020">{{cite journal |last1=Wu |first1=Jincai |last2=Ge |first2=Linquan |last3=Liu |first3=Fang |last4=Song |first4=Qisheng |last5=Stanley |first5=David |title=Pesticide-Induced Planthopper Population Resurgence in Rice Cropping Systems |journal=[[Annual Review of Entomology]] |volume=65 |issue=1 |date=January 7, 2020 |doi=10.1146/annurev-ento-011019-025215 |pages=409–429 |pmid=31610135 |s2cid=204702698 }}</ref> The [[International Rice Research Institute]] (IRRI) demonstrated in 1993 that an 87.5% reduction in pesticide use can lead to an overall drop in pest numbers.<ref name="Hamilton 2008">{{cite web |title=The pesticide paradox |last=Hamilton |first=Henry Sackville |publisher=[[International Rice Research Institute]] |date=January 18, 2008 |url=http://irri.org/knowledge/publications/rice-today/special-reports/science-shorts/the-pesticide-paradox |archive-url=https://web.archive.org/web/20120119053923/http://irri.org/knowledge/publications/rice-today/special-reports/science-shorts/the-pesticide-paradox |archive-date=January 19, 2012}}</ref>

[[File:Penggembala Bebek.jpg|thumb|left|A farmer [[Rice-duck farming|grazes his ducks]] in [[paddy field]]s, Central Java]]

Farmers in China, Indonesia and the Philippines have traditionally managed weeds and pests by the [[polyculture|polycultural]] practice of [[Rice-duck farming|raising ducks]] and [[Rice-fish system|sometimes fish]] in their rice paddies. These produce valuable additional crops, eat small pest animals, manure the rice, and in the case of ducks also control weeds.<ref name="Bezemer 2022">{{cite web |last=Bezemer |first=Marjolein |date=October 23, 2022 |title=Mixed farming increases rice yield |url=https://www.renature.co/articles/mixed-farming-increase-rice-yield/ |url-status=live |archive-url=https://web.archive.org/web/20191011124422/https://renaturefoundation.nl/2018/12/12/mixed-farming-increase-rice-yield/ |archive-date=October 11, 2019 |access-date=January 2, 2024 |website=reNature Foundation}}</ref><ref name="Cagauan Branckaert Van Hove 2000">{{cite journal |last1=Cagauan |first1=A. G. |last2=Branckaert |first2=R. D. |last3=Van Hove |first3=C. |title=Integrating fish and azolla into rice-duck farming in Asia |journal=Naga (ICLARM Quarterly) |volume=23 |issue=1 |pages=4–10 |year=2000 |url=https://aquadocs.org/bitstream/handle/1834/25720/na_2359.pdf?sequence=1&isAllowed=y |archive-date=March 14, 2024 |access-date=January 5, 2024 |archive-url=https://web.archive.org/web/20240314081726/https://aquadocs.org/bitstream/handle/1834/25720/na_2359.pdf?sequence=1&isAllowed=y |url-status=live }}</ref>

Rice plants produce their own chemical defences to protect themselves from pest attacks. Some synthetic chemicals, such as the herbicide [[2,4-Dichlorophenoxyacetic acid|2,4-D]], cause the plant to increase the production of certain defensive chemicals and thereby increase the plant's resistance to some types of pests.<ref name="Xin Yu Erb 2012">{{cite journal |last1=Xin |first1=Zhaojun |last2=Yu |first2=Zhaonan |last3=Erb |first3=Matthias |last4=Turlings |first4=Ted C. J. |last5=Wang |first5=Baohui |last6=Qi |first6=Jinfeng |last7=Liu |first7=Shengning |last8=Lou |first8=Yonggen |display-authors=5 |title=The broad-leaf herbicide 2,4-dichlorophenoxyacetic acid turns rice into a living trap for a major insect pest and a parasitic wasp |journal=[[New Phytologist]] |volume=194 |issue=2 |pages=498–510 |date=April 2012 |pmid=22313362 |doi=10.1111/j.1469-8137.2012.04057.x |doi-access= }}</ref> Conversely, other chemicals, such as the insecticide [[imidacloprid]], appear to induce changes in the gene expression of the rice that make the plant more susceptible to certain pests.<ref name="Cheng Shi Jiang 2012">{{cite journal |last1=Cheng |first1=Yao |last2=Shi |first2=Zhao-Peng |last3=Jiang |first3=Li-Ben |last4=Ge |first4=Lin-Quan |last5=Wu |first5=Jin-Cai |last6=Jahn |first6=Gary C. |title=Possible connection between imidacloprid-induced changes in rice gene transcription profiles and susceptibility to the brown plant hopper Nilaparvatalugens Stål (Hemiptera: Delphacidae) |journal=Pesticide Biochemistry and Physiology |volume=102 |issue=3 |pages=213–219 |date=March 2012 |pmid=22544984 |pmc=3334832 |doi=10.1016/j.pestbp.2012.01.003 |bibcode=2012PBioP.102..213C }}</ref>

Plant breeders have created rice cultivars incorporating [[plant resistance to insects|resistance to various insect pests]]. Conventional plant breeding of resistant varieties has been limited by challenges such as rearing insect pests for testing, and the great diversity and continuous evolution of pests. Resistance genes are being sought from wild species of rice, and genetic engineering techniques are being applied.<ref name="Makkar Bhatia Suri Kaur 2019">{{cite journal |last1=Makkar |first1=Gurpreet Singh |last2=Bhatia |first2=Dharminder |last3=Suri |first3=K.S. |last4=Kaur |first4=Simranjeet |title=Insect resistance in Rice (Oryza sativa L.): overview on current breeding interventions |journal=International Journal of Tropical Insect Science |volume=39 |issue=4 |date=2019 |doi=10.1007/s42690-019-00038-1 |pages=259–272|s2cid=202011174 }}</ref>

{{Anchor|Ecotypes|Ecotype|Cultivars|Cultivar}}