Effect of storage conditions on the survival of two potential biocontrol agents of nematodes, the fungi Paecilomyces lilacinus and Pochonia chlamydosporia

Abstract

The nematophagous fungi Paecilomyces lilacinus and Pochonia chlamydosporia have been extensively studied as biological control agents for plant-parasitic nematodes. This study describes the formulation of alginate pellets containing mycelia of these fungi and also describes the effect of storage conditions on shelf-life of the pellets. The shelf-lives of P. lilacinus and P. chlamydosporia, which were measured monthly for 6 months, were significantly improved at low temperatures and low water activity (a _w) values (<0.33). Vacuum did not affect the viability of the formulated P. lilacinus but increased the viability of P. chlamydosporia. Carbon dioxide reduced the activity of P. lilacinus as compared to ambient air but increased the activity of P. chlamydosporia. Nitrogen, however, significantly improved the viability of both fungi. The optimal parameters of each factor for our formulation of P. lilacinus and P. chlamydosporia included a temperature range of 4 to −20°C, a _w=0.12, and a nitrogen-filled atmosphere.

Keywords:

• formulation
• Paecilomyces lilacinus
• Pochonia chlamydosporia
• shelf-life
• storage conditions

Acknowledgements

We thank Professor Xiuzhu Dong of this Institute for the technical support during the atmosphere test and Professor B.A. Jaffee of University of California-Davis for reviewing and editing the manuscript. We also thank two anonymous reviewers for the critical review of the manuscript. This research was jointly supported by the Ministry of Agriculture of the People's Republic of China (nyhyzx07-050) and the Beijing Municipal Science & Technology Commission (D0706005040331 and D0705002040191).