ARS | Publication request: IMPROVING MICROGRANULE FORMULATIONS OF BIOINSECTICIDAL (BACILLUS THURINGIENSIS)

Submitted to: Association of Formulation Chemists Formulations Forum
Publication Type: Abstract Only
Publication Acceptance Date: March 5, 1999
Publication Date: N/A

Technical Abstract: We used a spray-drying process to produce sprayable powder formulations in which the protective ingredients were combined with the active agent in order to prevent disassociation during the mixing and application process. Only low-cost natural products were selected as formulation ingredients; and these included citric or lactic acid, pregelatinized corn flour, cornstarch, isopropyl alcohol, sugar, and corn oil. In diet incorporation tests against Helicoverpa zea (Boddie), Trichoplusia ni (Hubner), Heliothis virescens (F), and Spodoptera exigua (Cramer), initial insecticidal activity of spray-dried B. thuringiensis did not decrease due to processing when compared with unformulated technical B. thuringiensis. Cotton leaf bioassays using Ostrinia nubilalis (Hubner) showed that insecticidal activity of formulations exposed to artificial solar radiation (xenon light) for 8 h was significantly higher than unformulated B. thuringiensis exposed to solar radiation. Results demonstrated that it is possible to formulate B. thuringiensis by spray-drying using natural ingredients such as flours, sugar, and starch to form sprayable particles (0.25 mm) which extend the residual insecticidal activity of B. thuringiensis when exposed to simulated solar conditions.