Search

Coffee berry borer (Hypothenemus hampei), is one of the main pests affecting coffee production worldwide. This pest feeds and reproduces inside the berry reducing its weight and quality, causing losses up to 50%. Some strains of Bacillus have plasmids that incorporate cry and cyt genes, whose products have toxic properties to insects. Bacillus thuringiensis and Bacillus pumilus have been evaluated as entomopathogenic. The objectives of this study was to determine the potential of two native Bacillus strains (B. thuringiensis Bt3971 and B. pumilus Bp4185) isolated from coffee ecosystem of Puerto Rico as biocontrol of coffee berry borer. The presence of a 12 kbp plasmid was confirmed in Bt3971 and Bp4185, and a 116 kDa protein with entomopathogenic potential from Bt3971. After 48 h of treatment, Bt3971 (A590=0.8, approximately 1010 CFU ml-1) caused 55% mortality and 82% at 72 h in a population of insects. Bp4185 strain, at 72 h caused 55% mortality (A590=1.0, approximately 1012 CFU ml-1) and 46% at 96 h (A590=0.8). Both native bacterial strains, adapted to the environmental conditions of Puerto Rico, have potential for biological control of coffee berry borer.

Coffee berry borer (Hypothenemus hampei), is one of the main pests affecting coffee production worldwide. This pest feeds and reproduces inside the berry reducing its weight and quality, causing losses up to 50%. Some strains of Bacillus have plasmids that incorporate cry and cyt genes, whose products have toxic properties to insects. Bacillus thuringiensis and Bacillus pumilus have been evaluated as entomopathogenic. The objectives of this study was to determine the potential of two native Bacillus strains (B. thuringiensis Bt3971 and B. pumilus Bp4185) isolated from coffee ecosystem of Puerto Rico as biocontrol of coffee berry borer. The presence of a 12 kbp plasmid was confirmed in Bt3971 and Bp4185, and a 116 kDa protein with entomopathogenic potential from Bt3971. After 48 h of treatment, Bt3971 (A590=0.8, approximately 1010 CFU ml-1) caused 55% mortality and 82% at 72 h in a population of insects. Bp4185 strain, at 72 h caused 55% mortality (A590=1.0, approximately 1012 CFU ml-1) and 46% at 96 h (A590=0.8). Both native bacterial strains, adapted to the environmental conditions of Puerto Rico, have potential for biological control of coffee berry borer. [ABSTRACT FROM AUTHOR]

A genetically altered variant of Cry9Ca from Bacillus thuringiensis shows high potency against the spruce budworm, Choristoneura fumiferana Clemens. Its activity, as measured by feeding inhibition in frass-failure assays, is estimated to be four to seven times greater than B. thuringiensis subsp. kurstaki HD-1, the strain currently used in commercial products to control this insect. Bioassays against budworm of mixtures of the modified Cry9Ca and two of the Cry1A endotoxin proteins produced by HD-1 show neither synergism nor antagonism. Experiments with brush border membrane vesicles from budworm midgut revealed that Cry9Ca and the Cry1A toxins share a common binding site and that bound Cry9Ca can be displaced from the membrane to some extent by the Cry1A toxins. However, it is uncertain whether the binding site is actually the receptor molecule or a membrane protein associated with pore formation. [Copyright &y& Elsevier]