|Medrano-rold Eln, Hiram|
Submitted to: Society of Invertebrate Pathology
Publication Type: Abstract Only
Publication Acceptance Date: 7/21/1995
Publication Date: N/A
Citation: N/A Interpretive Summary:
Technical Abstract: Corn starch based formulations were used to compare the toxicity of six strains of Bacillus thuringiensis (Bt) belonging to four serovars. Laboratory fermented material was tested in laboratory bioassays and the most active strains were formulated and tested in the field. Granular formulations contained nixtamalized corn flour (commercial Mexican tortilla flour), mixed with sucrose, vegetable oil, formaldahyde, malachite green, isopropanol and water. Field tests were conducted on corn plots in a semi-arid region in central Mexico during 1994 and 1995, using 2 and 4% (1994) and 3% (1995), respectively, of spore-crystals concentrate. In 1994 the highest yields of corn were obtained in the plots treated with two HD strains, one Mexican strain and a chemical insecticide. The most striking differences were observed when the strains were used at a concentration of 2% spore-crystal complex. In the 1995 field test, the three most toxic strains were evaluated individually or by mixing two at a time in the same granular formulation at a total dose of 3%. A formulation prepared two years earlier was also tested. The highest yields of corn were obtained with strain HD-263 (kurstaki), which had originally shown the highest efficacy in bioassays, and with strain GM-10 (aizawai), which was prepared 2 years previously.