Abstract
Bacillus thuringiensis Berliner was encapsulated within a starch matrix and assayed for biological activity against neonate and second-instar larvae of the European corn borer, Ostrinia nubilalis (Hübner). When larvae ingested encapsulated B. thuringiensis, they digested the starch matrix and released into their guts B. thuringiensis crystals and spores, which initiated infection. Nearly 100% mortality occurred at all dosages and concentrations tested whenever the starch granules were hydrated and high relative humidity conditions (>80%) were maintained during the 24-h exposure period of the assay. Encapsulated B. thuringiensis stored in the laboratory for 4 mo exhibited no detectable decrease in pathological activity.