Survivability of P. oxalicum T3.3 bioformulation on carrier materials and storage temperature
Abstract
Good bioformulation play crucial roles in the successfully of commercialize biological control products. The development of bioformulation is necessary to improve product stability, delivery and bioactivity. The aim of this study is to assess the shelf life of P. oxalicum T3.3 conidia in the different ratio(1:1,1:2,2:1) of Biochar:Biocompost (BcBp) and Peat:Vermiculite (PtVm) and temperature (4ºC and room temperature) for 6 months. The results showed that P. oxalicum T3.3 was able to sustain highest viable cell (CFU) at 4ºC storage temperature. BcBp and PtVm have the highest cell viability at ratio 2:1 and 1:1, respectively. Both BcBp and PtVm showed potential carriers for the development of biofungicide for agriculture purposes.
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Introduction
Fungi have been a great spotlight as a biological control agent and large scale of work has been borne in order to find fungi with a good potential as a fungicides (Lopez, 1998). Some species of fungi have the abilities to secrete active substances that can be lethal to certain life form (Santamarina et al., 2002). Most fungal showed antagonistic effect to certain bacteria or fungi that cause plant disease. Penicillium spp. is one of the potential biological agent that capable to control certain pathogenic fungal species by inducing resistance in plant and by its metabolites (Narayanasamy, 2013). Besides, Penicillium spp. has been reported to have ability to suppress Fusarium and Verticillium wilt of tomato plant (Whipps, 2001). However, the use of fresh cells of potential biological control agent (BCA) have been widely studies in controlling plant disease (Mahdy et al., 1987; Larsen & Knechel, 1997; Cal & Melgarejo, 2000 and Shojaee et al., 2014). Even though it is effective and suitable for research purposes but it is not practical to be used by farmers. The inconsistency of the fresh cells of BCA makes it impossible for commercialization and longer time storage.
Formulated biological control products must be able to retain their similar productivity to the fresh cells (Janisiewicz & Jeffers, 1997). The major concern of the commercialize products are the stability of the shelf life of biological control in the market. Baker & Henis (1990) highlight that a commercialize product must be able to retain their stability for at least one year and must be stored at room temperature. Apart from that, the formulated product must be easy to handle and have stability over a range of-5 to 35 ºC (Junaid et al., 2013). Formulation of the biological control is the mixture of active ingredients such as conidia with the inert material such as surfactant in order to modify the physical characteristics to more desirable form (Junaid et al., 2013). Thus, the aim of this project is to assess the shelf-life of P. oxalicum T3.3 conidia indifferent ratio of carrier and storage temperature. The present study will increase knowledge on the development of commercialize biological control products for agriculture purpose.
Conclusion
In conclusion, both bioformulation were able to retained high CFU number during storage temperature 4 ºC compared to room temperature for 180 days. In comparison, BcBp bioformulation has higher cell viability with log 5.43±0.13 CFU/mL whereas PtVm bioformulation with log 4.46±0.15 CFU/mL. Bioformulation was able to preserve high cell population because of the presence of moisture surrounding the cells which help to reduce water loss in the formulation. Apart from that, the both bioformulation also were tested for their effect on the different carrier ratio and study found that BcBp were able to maintain high CFU with log 5.63±0.47 CFU/mL at 2:1 while ratio 1:1 of PtVm recorded high CFU with 5.43±0.13 CFU/mL. A good carrier choice plays an important role in preserving cell viability. Present study showed that mixture of biochar and biocompost as good carriers for microbial habitat compared to peat and vermiculite.
