The paper describes the breed characteristics, production performance including reproduction, growth, carcass and meat quality traits of the Tongcheng pig, one of the indigenous pig breeds suitable for a hybrid maternal line in central China. Based on the field investigation and data statistics from the farm recordings, the Tongcheng pig has early sexual maturity indicators, and the average litter size is 8.5 for first parity and 9.3 and 11.3 for the second and subsequent parities respectively. In a three-way crossing project launched recently, using the Tongcheng pig as the maternal parent and Landrace or Yorkshire pigs as the paternal parent, the performance testing results showed that Tongcheng pigs had a lower growth and meat production performance than these commercial pigs, but had superior meat quality. The production performance of the two crossing groups Landrace/Yorkshire/Tongcheng pigs) (LYT) and Yorkshire/Landrace/Tongcheng pigs) (YLT) were improved in comparison to their parent lines, and the results further indicated that the LYT cross is a tri-crossing style convenient for farm and village areas in central China. Meanwhile, effective management measures taken towards Tongcheng pig preservation, and a genetic diversity evaluation on the Tongcheng pig were reviewed. This paper offers the Tongcheng pig as a case study for the maintenance and utilization of indigenous pigs in China, which is rich in pig breeds but is also confronting the pig resource crisis.

The larvicidal activity of two entomopathogenic bacteria Bacillus thuringiensis H-14 and B. sphaericus 1593 against mosquito larvae of Culex pipiens has been evaluated. According to LC50 values obtained, B. thuringiensis (4.6 x 105 spores/ml) proved to be highly pathogenic to fourth instar larvae than fi. sphaericus (4.2 x 106 spores/ml).

Larval treatment with LC50 levels of both pathogens affected the reproductive potential of surviving adults during two successive gonotrophic cycles. These treatments caused insignificant changes in some basic morphometric characteristics of mosquito females that developed from surviving larvae.