An SEM Study of the Sporulation Process of Pandora Neoaphidis and Neozygites Fresenii

The objective of this study was to investigate the development of fungal pathogens in aphid hosts and identify structures characteristic of each fungal species. Aphids infected by Pandora neoaphidis and Neozygites fresenii were incubated for different time periods and examined by SEM. In P. neoaphidis, hyphal bodies concentrated in clumps beneath the cuticle and these formed rosette patterns consisting of a central structure, the developing cystidium, surrounded by developing conidiophores. Rhizoids were the first structure emerging from the P. neoaphidis-killed aphid. Primary spores were formed after 6 h and secondary spores after10 h of incubation. In N. fresenii, the conidiophores did not group together to form rosette patterns as in P. neoaphidis. Rhizoids were not formed by N. fresenii but infected aphids were held to the leaf by their mouth parts. The primary spores of N. fresenii wereformed at 2 h and were generally round or ovoid in shape. These primary conidia formed long slender capillary tubes that produced secondary conidia which were almond shaped and possessed a terminal mucoid hapteron. Saprophytic fungi began to develop on N.fresenii-killed aphids at 24h and by 48 h the whole cadaver was covered. In N. fresenii, spore formation occurred earlier than in P.neoaphidis, but numbers of spores formed by P. neoaphidis were higher than by N. fresenii.