Submitted to: International Coloquim on Invertebrate Pathology and Microbial Control
Publication Type: Abstract Only
Publication Acceptance Date: April 30, 2002
Publication Date: August 15, 2002
Citation: NIELSEN, C., HAJEK, A.E., HUMBER, R.A., BRESCIANI, J., EILENBERG, J. SOIL AS AN ENVIRONMENT FOR WINTER SURVIVAL OF APHID-PATHOGENIC ENTOMOPHTHORALES. INTERNATIONAL COLOQUIM ON INVERTEBRATE PATHOLOGY AND MICROBIAL CONTROL. 2002.
Fungus regularly causes epizootics among aphid pests suggesting great potential for using PANDORA NEOAPHIDIS for microbial control of aphids either by inoculation or by conservation of the environment. Regardless of the strategy, a better understanding of the epizootiology is, however, essential for success. So far, most attention has been given to the effect of P. NEOAPHIDIS on aphid populations in economically important crops during the summer months, whereas knowledge concerning performance during the winter and initiation of infections in spring is limited. In the lab the winter survival of PANDORA NEOAPHIDIS was studied for both discharged primary conidia and hyphal bodies inside aphid cadavers after storage on moist soil at different temperatures. The activity of the inoculum was quantified by the ability to produce replicate conidia as well as the ability to infect aphids. No effect of inoculum type was found, and both primary conidia and hyphal bodies retained the ability to initiate infections in aphids after storage for at least 14 days at 20oC, 32 days at 10oC and 64 days at 5oC. Morphological studies of the inoculum suggest that P. NEOAPHIDIS may survive unfavorable conditions as thick-walled conidia also known as loricoconidia. Furthermore, P. NEOAPHIDIS and CONIDIOBOLUS OBSCURUS were first documented in field-collected soil in early spring by baiting the soil with aphids. We believe that germination of overwintering inoculum is stimulated by host-induced factors since inoculum apparently responded to the presence of aphids.