**Acknowledgement**

28 The Complex World of Polysaccharides

**45. Biopesticide** 

**46. Bionematicide** 

**47. Conclusions** 

well as new applications.

before the application.

containing these microorganisms to increase biopesticide effectiveness, to provide a favorable developmental environment and resistance against adverse conditions [239]. New chitosan derivatives with insecticidal or fungicidal properties may thus serve as good alternatives for broad-spectrum and highly persistent pesticides because they are non-toxic

Tricoderma sp. and Bacilus sp. are microorganisms which often increase chitin and chitosan production, enhancing its efficiency to control pathogenic microorganisms and pests [238]. Native populations of biocontrol microorganisms became increased by adding chitin in soils infected with pathogenic agents. Thereafter, these endogenous control strains can be isolated, cultured and potentially used as biological controls. It has also been demonstrated a significant increase in chitinolytic microorganisms even in very infertile soils like in dunes,

Nematodes proliferation can be controlled when chitosan is applied in soil, because chitinolytic microorganisms proliferate destroying nematode eggs and degrading the chitincontaining cuticle of young nematodes [240]. Because of the high content of nitrogen in chitosan and chitin molecules, concentrations of ammonia emissions increase turning toxic

Further research is still required to find more applications of chitosan in agriculture, but nowadays this polymer means to be a cheap and easy material to deal with crop problems

Scientific databases reveal thousands of articles and patents related to chitin, chitosan and its derivatives and increasingly opens up new possibilities to produce new derivatives as

The answer to the question if the chitosan is a "new panacea", is given by the multiple applications for this new biopolymer and its predecessor, the chitin. Two hundred years have passed since its discovery and this biopolymer has shown unique qualities that many other polymers do not have, as it can be applied in different areas like in the agricultural

As seen in this chapter, chitosan's behavior in different applications within diverse areas, is governed by its molecular weight, degree of deacetylation, degree of polymerization and source of obtention. Twenty years ago the articles published did not provide data on the characterization of material but today most papers focus on the properties of the polymer

to vertebrates and humans, and have a biodegradable matrix.

improving soil microbiota and its properties [239, 241].

pre-harvest, harvest and post-harvest level.

to nematodes which principally affect plant roots and shoots [239, 243].

and medical field or in related areas such as pharmacy and biomedical.

Gabriela Montaraz Miranda, Rosa Guadalupe Valadez Olguin and Ana María Sixto Berrocal for her technical assistance.

To PAPITT Program No. IT220411 Estudio fitopatológico, bioquímico y molecular de la respuesta contra estreses bióticos y abióticos en plántulas de maíz. For the financial support.

To PAPIME Program No. PE203211 Elaboración de material didáctico para las diferentes estrategias utilizadas en la enseñanza de la biotecnología de última generación. For the financial support.
