The Effect of an Entomopoxvirus on Larval Populations of an Undescribed Midge Species in the Chironomus decorus Complex Under Laboratory Conditions 12

Larvae of an undescribed species in the Chironomus decorus complex reared at densities ranging 0.3–8.4 larvae/cm 2 were inoculated with an entomopoxvirus originally found in a field population of the same midge. Although inclusion bodies rarely developed in infected larvae (<2%) reared at low population densities, there was significant early-instar and pupal mortality associated wIth exposure of 1st-instar larvae to the virus. At higher densities (5 and 7.5–8.4 larvae/cm 2 ), the proportion of larvae showing signs of infection by developing inclusion bodies increased, and larval and pupal mortality were also higher than in non-exposed populations reared at the same densities. The effect of the EPV was found to be inversely proportional to the age of the population at the time of virus treatment and directly proportional to the concentration of the EPV.