On the distribution of Bacillus thuringiensis and closely related Bacillus cereus in Egyptian soils and their activity against cotton insects
1986
Salama, H.S. (National Research Centre, Cairo (Egypt). Lab. of Pests and Plant Protection) | Foda, M. | Zaki, F. | Ragaei
During one-year study, a survey was made on the distribution of Bacillus thuringiensis and Bacillus cereus in the Egyptian soils. Samples of various types of soils were collected from fields that had not previously been sprayed with B. thuringiensis. For isolation a technique was devised to eliminate the growth of the majority of soil bacteria, fungi and other undesirable flora. High bacilli counts were detected in most fertile clay soils, while sandy soils always had low counts. Some of the isolates were found to be active against the lepidopterous cotton pests Spodoptera exigua and Heliothis armigera, while none of the isolates exhibited a significant biological activity against Spodoptera littoralis. There is a strong indication that the bacilli isolates observed were present naturally in the Egyptian soils. Studies are being conducted with more isolated strains and identification of the isolated cultures are underway
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