INVASION AND DEVELOPMENT OF VERTICILLIUM-LECANII IN THE WESTERN FLOWER THRIPS, FRANKLINIELLA-OCCIDENTALIS

Conidia of Verticillium lecanii, coated with mucilage, adhered to all surfaces of the western flower thrips (Frankliniella occidentalis). Mu cilage continued to be secreted during germination and was particularl y evident around the hyphal tips and at penetration sites. Both conidi a and hyphae produced narrow pegs which penetrated the cuticle and the cuticle in juxtaposition with growing hyphae was dissolved. Verticill ium lecanii typically colonized the surface of the insect prior to, or concomitant with penetration of the host cuticle. infected insects di ed before the pathogen had substantially colonized the haemocoel but o nce in the haemocoel, hyphal bodies rapidly multiplied and invaded vir tually all tissues and organs. The hyphae eventually emerged from the diseased insect and differentiated into conidiophores which produced c onidia coated in mucus.