CHITOSAN MIXED WITH BENEFICIAL FUNGAL CONIDIA OR FUNGICIDE FOR BEAN (Phaseolus vulgaris L.) SEED COATING

Chitosan has been recommended for agricultural applications as an adherent, additive or coating for seeds. It has also been reported to induce endogenous defenses and promote the establishment and development of seedlings. However, these properties seem to be associated to the evaluated species. In this paper, two kinds of chitosan coatings were generated and mixed with fungicide and with beneficial fungi conidia (Beauveria bassiana and Trichoderma harzianum). Chitosan from two sources (shrimp and insect Pterophylla beltrani) was used. Coating mixtures were applied on the surface of bean (Phaseolus vulgaris L) seeds by immersion. Neither coating treatment with chitosan affected seed germination. In the case of coating with fungicide, the shrimp chitosan allowed gradual release of the chemical agent on the seed surface for a longer time. Moreover, an important part of B. bassiana conidia incorporated into the coatings germinated, indicating that this type of biological agent can be used in coatings to provide seeds with biological protection. Little germination of T. harzianum conidia was observed. More studies are needed to establish times and conditions to control germination of conidia in the. coatings.