Fruiting body of Paecilomyces fumosoroseus formed on unpolished rice medium supplemented with 20% (w/w) silkworm pupae after 40 days of incubation at 25 o C under 100 lux. 

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... conditions of P. fumosoroseus. Effect of pH: The pH value suitable for a favorable growth of P. fumosoroseus was obtained in the range of pH 6~9. Choi et al. (1999) reported that mycelial growth of P. japonica was optimal at pH 7. Shim et al. (2003) also reported that P. sinclairii showed maximal mycelial growth at pH 8. However, the mycelial growth and den- sity of P. fumosoroseus was almost identical in the range of pH 6~9 (Fig. 2). These results suggest that P. fumoso- roseus may have a broad pH range for its favorable myce- lial growth in nature. Effect of temperature: The temperature suitable for the mycelial growth of P. fumosoroseus was obtained at 25 o C (Fig. 3) and the result was similar to that of Lee et al. (1999). Lee et al. (1999) reported that the mycelial growth of P. fumosoroseus had been expedited gradually in pro- portion to the rise of temperature and was the most suit- able at 25 o C. Even though the mycelial growth of P. fumosoroseus was favorable at the range of 20 to 25 o C and had been expedited in proportion to the rise of tem- perature, the mycelial growth appeared to be suppressed at the temperature higher than 30 o C (Fig. 3). Since most of entomopathogenic fungi has been known to complete their life cycle under the humid, cool deposits covered with fallen leaves ( Sung et al., 1997), it is reasonable to pre- dict that the mycelial growth of P. fumosoroseus was good in the temperature range of 20~25 o C. Screening of favorable culture media: Ten different culture media were used to screen the optimal mycelial growth of P. fumosoroseus. Of 10 culture media, Hamada medium was the most suitable for a favorable growth of P. fumosoroseus (Table 2). This result is corresponded with that of P. sinclairii which had been reported by Shim et al. (2003). Even though the mycelial growth of P. fumosoroseus and P. sinclairii was optimal on Hamada medium, the mycelial growth of Grifola umbellata was very poor on Hamada medium. This contradictory result indicates that taxonomically distinct fungal groups may have different nutritional requirement. Even though the mycelial growth in 10 different media showed wide range of variations (55.5~77.0 mm), the mycelial density were compact in 9 of 10 culture media tested ( Table 2). Effect of carbon and nitrogen sources: Dextrin and histidine were screened as suitable carbon and nitrogen source for the mycelial growth of P. fumosoroseus (Table 3 and Table 4). The colony diameter of P. fumosoroseus after 14 days of incubation were recorded 78.0 mm in dextrin and 74.5 mm in histidine containing basal media, respectively. The mycelial density of P. fumosoroseus showed thin appearances in all carbon source, whereas compact appearances were observed in 16 nitrogen sources. Shim et al. (2003) also reported that P. sinclairii grew very well in basal medium which contained dextrin and glutamine, respectively. Since P. fumosoroseus and P. sinclairii belong to genus Paecilomyces of Hypho- mycetes, Deuteromycota, they are taxonomically consid- ered as very close species (Lacey et al., 1999). However, the nutritional requirement for the mycelial growth of P. fumosoroseus and P. sinclairii seems to be different. Effect of C/N ratio: Optimum C/N ratio suitable for a favorable growth of P. fumosoroseus was observed on the culture media which were adjusted to C/N ratio of 40:1. On the culture media which were mixed with 1% glucose as carbon source and then adjusted to the ratio of 30:1, P. sinclairii showed the most favorable mycelial growth (Shim et al., 2003). Despite a gradual rise of 1%, 2%, 3% and 4% glucose, C/N ratio of 40:1 showed the most favorable mycelial growth of P. fumosoroseus as com- pared with other C/N ratios ( Table 5). Effect of cereal extract media: Sung et al. (1993) reported that the mycelial growth of Cordyceps militaris was favorable on the artificial medium supplemented with silkworm pupae, rice powder or wheat powder. Shim et al. (2003) also reported that silkworm pupae supple- mented to the cereal extract medium showed favorable mycelial growth of P. sinclairii. The mycelial growth of P. fumosoroseus was optimal on corn meal agar supple- mented with 10~30% of silkworm pupae (Table 6). Partic- ularly, the mycelial growth of P. fumosoroseus recorded 71.9 mm in PDA plate with maximal value on corn meal agar supplemented with 30% of silkworm pupae. Based on these results, silkworm pupae may contain good nutritional sources to promote mycelial growth of P. fumosoroseus. Formation of fruiting body: The fruiting body of P. fumosoroseus was formed abundantly on an unpolished rice medium supplemented with 20% (w/w) silkworm pupae at 25 o C under 100 lux (Fig. 1, Table 7). Shim et al. (2003) reported that fruiting body of P. sinclairii was formed after 10 days of incubation at 25 o C under 500 lux. The fruiting body of P. fumosoroseus was formed after 12 days of incubation at 25 o C under light condition. But, unlike the P. sinclairii, the fruiting body of P. fumosoro- seus was formed more abundantly under 100 lux than 500 lux. The fruiting body of P. fumosoroseus was not formed at 30 o C. This result also coincide with mycelial growth of the fungi which was suppressed at 30 o C (Fig. 3). Even though P. fumosoroseus have been considered as a good candidate for biocontrol of insect pests, there has been no report that P. fumosoroseus was used commer- cially for the biocontrol agent in Korea (Altre et al., 1999;Cantone and Vandenberg, 1999;Lacey et al., 1999;Lee et al., 1999;Nam et al., 2000). To develop P. fumosoro- seus as a mycoinsecticide, it is necessary to develop culture method to produce fruiting bodies in in vitro condition. In this study, the conditions for optimal myce- lial growth and fruiting body formation of P. fumosoro- seus was developed for the first time in Korea. Thus, the basic information obtained from this study can be used for the mass production of fruiting bodies of P. fumosoroseus. ...