Description of Bacillus thuringiensis wratislaviensis (H‐47), a new serotype originating from WrocŁaw (Poland), and other soil isolates from the same area

Twenty‐four Bacillus thuringienis (Bt) strains were isolated and examined in respect of serotype, plasmid content crystal‐composing proteins and insecticidal activity. Strains PO1–PO11 and PO14–PO15 were recognized as B. thuringiensis kurstaki H3a3b3c. The strains PO12 and PO13 were found to share a common novel antigen determining the new serotype H‐47, and were designated as serovar wratislaviensis. Further investigations showed that all strains carried multiple plasmids (for example six different large plasmids in PO12 strain) and formed crystals composed of either two proteins, 135·8 kDa and 66·2 kDa (strains PO1–PO11 and PO14–PO24), or on protein, 66·2 kDa (strains PO12 and PO13). Preliminary toxicity tests with crude suspensions of spores and crystals showed rather low activity (<50% mortality) against fruitfly larvae and nymphs of cockroaches and high toxic effects (up to 90% mortality) against house fly larvae.