ISOLATION OF MOSQUITO-LARVICIDAL BACILLUS SPHAERICUS FROM THE SOIL SAMPLES COLLECTED IN HAINAN, CHINA
我国海南省杀蚊球形芽孢杆菌的分离和分布

During 1992-1993, one hundred and fifty eight of vanous soil samples collected in fourteen counties or cities in Hainan Province. With a selected medium (PBMYS), totally seventy-three strains of Bacillus sphaericus, possessing larvicidal achvity against Culex quinquefasciatus, were isolated. The rate of active strains isolated is 34.2% in the total of samples. The seroIogical study showed that most of newly isolates were belonging to serotype Wash except that tWo strains, 47-6b and 124-3, were belonging to H6.The acetone powders prepared from several newly isolates of H5aa5b, were highiy toxic to the larvae of C quinquefasciatus. Two of them, 228-2 and 117-1, had a calculated Potency of 2721 and 2331ITU/ mg respechvely. In contraSt with the potent sthen 2362, it had a potency value of 2218ITU/mg.