Sprayable self-encapsulating starch formulations for Bacillus thuringiensis

Under glasshouse conditions, various cornstarches and adjuvants were examined as encapsulating agents in sprayable formulations for Bacillus thuringiensis subsp. kurstaki Berliner. When these materials were suspended in water and tested for physical factors such as viscosity, clumping, and retention on plant surfaces, a range of responses was observed. All formulations tested had acceptable viscosity, but some formulations clumped. When applied to cotton leaves, certain formulations remained less than 4 d, whereas others remained greater than 2 wk. One of these formulations containing equal parts of Mira-sperse (a commercially available pregelatinized cornstarch) and sucrose (6% total solids) was selected for testing persistence of B. thuringiensis insecticidal activity against Ostrinia nubilalis Hübner neonate larvae. When encapsulating agents were present, insecticidal activity decreased over a 2-wk period significantly more slowly than when encapsulating agents were absent. This indicates an enhanced persistence of B. thuringiensis under glasshouse conditions. Implications of a sprayable self-encapsulating formulation for B. thuringiensis are discussed.     

Corticotropin-releasing hormone inhibits maternal behavior and induces pup-killing

Behavioral responses to stressors and the effects of stressors on maternal behavior change with mothering experience. Corticotropin-releasing hormone (CRH) is released by stressors and produces stress-like behavioral effects. We tested the effects of ICV infusion of ovine CRH (0.5-4 ug) on pup-directed behaviors in ovariectomized, ovarian steroid-treated virgin rats that were either naive to pups or that had three days of mothering experience. CRH inhibited maternal behavior in naive and experienced rats in a dose-related manner. The magnitude and duration of inhibition, especially at the 1 ug dose, were less in rats with mothering experience. Higher doses of CRH (1 - 4 ug) significantly increased pup-killing in rats that were naive to pups. In contrast, CRH produced no pup-killing in rats with mothering experience.