Editing Caterpillar (section)

== Economic effects ==

[[File:hypsipyla.jpg|thumb|''[[Hypsipyla grandela]]'' damages [[mahogany]] in Brazil]]

Caterpillars cause much damage, mainly by eating leaves. The propensity for damage is enhanced by [[monoculture|monocultural]] farming practices, especially where the caterpillar is specifically adapted to the host plant under cultivation. The [[cotton bollworm]] causes enormous losses. Other species eat food crops. Caterpillars have been the target of [[pest control]] through the use of [[pesticide]]s, [[biological control]] and [[agronomy|agronomic]] practices. Many species have become resistant to [[pesticide]]s. Bacterial toxins such as those from ''[[Bacillus thuringiensis]]'' which are evolved to affect the gut of Lepidoptera have been used in sprays of bacterial spores, toxin extracts and also by incorporating genes to produce them within the host plants. These approaches are defeated over time by the evolution of resistance mechanisms in the insects.<ref>[http://www.dec.ny.gov/animals/7111.html Tent Caterpillars and Gypsy Moths] {{Webarchive|url=https://web.archive.org/web/20130910190317/http://www.dec.ny.gov/animals/7111.html |date=2013-09-10 }}. Dec.ny.gov. Retrieved on 2012-08-14.</ref>

Plants evolve mechanisms of resistance to being eaten by caterpillars, including the evolution of chemical toxins and physical barriers such as hairs. Incorporating [[Plant defense against herbivory|host plant resistance]] (HPR) through plant breeding is another approach used in reducing the impact of caterpillars on crop plants.<ref>{{cite journal|title=Transgenic Host Plant Resistance to Insects—Some Reservations|author1=van Emden |author2=H. F. |journal=Annals of the Entomological Society of America|volume=92|issue=6|year=1999|pages=788–797|doi=10.1093/aesa/92.6.788}}</ref>

Some caterpillars are used in industry. The [[silk]] industry is based on the [[bombyx mori|silkworm]] caterpillar.