Abstract
A method to encapsulate microorganisms that have potential to control plant diseases was tested. Aqueous solutions containing 1% sodium alginate and 10% Pyrax wer comminuted in a blender. Solutions were amended singly with either ascospores or conidia of Talaromyces flavus (isolate Tfl or Tfl-1); conidia of Gliocladium virens (isolate GL3), Penicillium oxalicum or Trichoderma viride (isolate T-1-R9); or cells of Pseudomonas cepacia (isolate POP-S1). The alginate-Pyrax-propagule suspension was dripped through Pasteur pipettes into a solution of either 0.25 M CaCl2 or 0.1 M Ca gluconate which caused the formation of solid aggregates. The aggregates were dried overnight and stored under room conditions. Populations of encapsulated organisms were estimated after 0, 2, 4, 8 and 12 wk by dissolving the pellets in a mixture of 8.7 .times. 103 M KH2PO4 and 3.0 .times. 10-2 M Na2HPO4, and dilution plating on semiselective media. All fungi, but not Pseudomonas, were viable after pellet formation in CaCl2. All organisms were viable longer after pellet formation with Ca gluconate. Initial populations ranged from 105 to 108 propagules per milliliter of alginate suspension. These populations declined during the test period losses were 10- to 100-fold after 4 wk.