Development and selection of formulation matrices for microencapsulation entomopathogenic agents against Spodoptera exigua.

Several microencapsulating matrices were designed from completely biodegradable natural compounds and their feeding stimulant effect was evaluated in Spodoptera exigua which is an cosmopolitan lepidopteran pest. Microencapsulating matrices were prepared based on a modified grenetin, pectin and corn-starch as encapsulating agent and powdered corn-spike, sorgum leaves, alfalfa, cabbage and corn cob powdered as feeding stimulants. From the combination of these ingredients, sixteen types of granules were obtained and evaluated in feeding preference bioassays with neonate larvae of Spodoptera exigua. The larvae exhibited a high feeding preference to microencapsulating matrices containing feeding stimulants, being more preferred the corn-spike and cabbage additives than the natural food. The most accepted marices were the contituid for Grenetin- cabbage and grenetin- corn spike.