ENTRAPMENT OF BIOLOGICAL-CONTROL AGENTS APPLIED TO ENTOMOPATHOGENIC NEMATODES

Hydrogels of alginate, phospho guar gum, carboxymethyl guar gum, k-car rageenan and cellulose sulphate, respectively were tested to find easi ly redissolvable gels. The entomopathogenic nematode, Heterorhabditis sp., was entrapped in calcium alginate beads, calcium alginate hollow spheres and foils made from different hydrogels. Emigration from calci um alginate beads after 7 days of storage was 100 % at room temperatur e and was lowered to 6 % at 6-degrees-C, whereas no emigration from ca lcium alginate hollow spheres was found at either temperature. Highly concentrated polymer foils produced on gauze showed reduced emigration with a survival of 80 % after 24 h compared to foils produced on glas s slides. Calcium alginate beads can be used for a controlled release of the nematode into the environment, while hollow spheres and foils a re suitable for storage.