SUSCEPTIBILITY OF SEVERAL FOREST INSECTS OF BRITISH COLUMBIA TO COMMERCIALLY PRODUCED BACILLUS THURINGIENSIS .I. STUDIES ON PHYSIOLOGICAL PROPERTIES OF SOME COMMERCIAL PRODUCTS

The results of a comparative study of several industrial preparations of Bacillus thuringiensis are presented. The study included (1) production of spores and crystals on various culture media; (2) differences in the normal biochemical reactions of the products; (3) antibiotic or bacteriostatic effect of local foliage extracts on the bacterial growth and endotoxin synthesis; (4) miscibility of various spray additives (sticker-spreaders) with the different bacterial formulations; (5) the effect of these additives on the biological and physiological characteristics of the pathogen. The data indicated that (1) Spore viabilities were considerably higher in two Thuricide (Bioferm, Wasco) formulations than in the other products tested. (2) The spore/crystal ratios for most of the products were about the same regardless of the growth medium used. (3) Some spray additives were not miscible with the formulations tested. (4) Spray additives affected the rate of sporulation and toxic protein synthesis, especially when bacteria were grown on beef extract, blood agar, and urea slants. (5) Some bacteria, challenged with spray additives, lost their ability to break down disaccharides (maltose, trehalose, sucrose) and some hexoses (levulose, mannose, glucose); other additive-challenged bacteria gained the ability to break down salicin, rhamnose, arabinose, dextrin, galactose, and mannitol. (6) The ability of the organism to hydrolyze starch may be changed by some additives. (7) The additives tested had no effect on the viability of spores from Thuricide S7-150 or Entobacterine 3. (8) Ethyl acetate extracts of foliage from some trees (Quercus garryana, Pseudotsuga menziesii, and Abies grandis) completely inhibited the growth and toxic protein synthesis of Bacillus thuringiensis var. galleriae. The results show the need for laboratory testing of samples of B. thuringiensis prior to using them in the field. © 1969.