Use of chitin to improve a Beauveria bassiana alginate-pellet formulation

Abstract

A study was undertaken to evaluate optimum concentrations of chitin in sodium alginate pellet formulations to enhance conidia production. Chitin concentrations tested were 0, 0.5, 1, 2, 3 and 4% (w/v), with (2%, w/v) or without wheat bran. The different chitin-wheat bran pellet combinations were prepared with Beauveria bassiana isolate Qu-B306 at 10⁸ conidia mL^–1. After 21 days of incubation in a humid chamber at 28°C, conidia production was assessed. Improvements up to three times the initial conidia number were achieved using 2% chitin and 2% wheat bran. Higher levels of chitin decreased the number of conidia per pellet. For all chitin concentrations, conidia number increased with the addition of wheat bran (P≤0.05). Contamination by saprophytic fungi was reduced by the incorporation of chitin in the pellet formulation.

Keywords:

• Entomopathogenic fungi
• Beauveria
• alginate formulation
• encapsulation
• mycoinsecticide

Acknowledgments

This study was supported by a grant from the National Fund for Scientific and Technological Development (Fondecyt no. 1030037) from the National Commission of Scientific and Technological Research (Conicyt) of Chilean Government. We thank Bioagro S.A., Chile, for kindly providing the chitin used in this research.